Analysis of genotypes on 850 newborns with SLC26A4 single-allele mutation and the phenotypes of those with second variant / 中华耳鼻咽喉头颈外科杂志

Objective: To clarify the phenotypes of the newborns with SLC26A4 single-allele mutation in deafness genetic screening and second variant; to analyze the SLC26A4 genotype and hearing phenotype. Methods: 850 newborns born in Beijing from April 2015 to December 2019 were included and there were 468 males and 382 females. They received genetic deafness screening for 9 or 15 variants, with the result of SLC26A4 single-allele mutation. Firstly, three step deafness gene sequencing was adopted in this work, i.e., the first step was "SLC26A4 gene whole exons and splice sites" sequencing; the second step was "SLC26A4 gene promoter, FOXI1 gene and KCNJ10 gene whole exons" sequencing; and the third step was detection for "SLC26A4 gene copy number variation". Secondly, we collected the results of newborn hearing screening for all patients with the second mutation found in the three step test, and conducted audiological examinations, such as acoustic immittance, auditory brainstem response and auditory steady state response. Thirdly, for novel/VUS mutations, we searched the international deafness gene database or software, such as DVD, ClinVar and Mutation Taster, to predict the pathogenicity of mutations according to the ACMG guideline. Lastly, we analyzed the relationship between genotype and phenotype of newborns with SLC26A4 single allele mutation. Results: Among 850 cases, the median age of diagnosis was 4 months. In the first step, 850 cases were sequenced. A total of 32 cases (3.76%, 32/850) of a second variants were detected, including 18 cases (2.12%, 18/850) with identified pathogenic variants; 832 cases were sequenced and 8 cases of KCNJ10 gene missense variants were detected among the second step. No missense mutations in the FOXI1 gene and abnormal SLC26A4 gene promoter were detected; the third step sequencing results were all negative. Genotypes and hearing phenotypes included 18 cases combined with the second clear pathogenic variant, 16 cases (16/18) referred newborn hearing screening and 2 cases (2/18) passed in both ears; degree of hearing loss consisted of 18 profound ears (18/36), 13 severe ears (13/36) and 5 moderate ears (5/36); audiogram patterns comprised 17 high frequency drop ears (17/36), 14 flat ears (14/36), 3 undistinguished ears (3/36), and 2 U shaped ears (2/36); 11 cases underwent imaging examination, all of which were bilateral enlarged vestibular aqueduct. As for 22 cases of other genotypes, all passed neonatal hearing screening and the hearing diagnosis was normal, including 9 cases with VUS or possibly novel benign variants, 8 cases with KCNJ10 double gene heterozygous variants, and 5 cases with double heterozygous variants. Conclusions: The probability of individuals with SLC26A4 single-allele variant who merge with a second pathogenic variant is 2.12%, all of which are SNV, which can provide scientific basis for the genetic diagnosis and genetic counseling of SLC26A4 variants. Those who have merged with second pathogenic variant are all diagnosed with sensorineural hearing loss. Patients with KCNJ10 gene mutations do not manifest hearing loss during the infancy, suggesting the need for further follow-up.

Phenotype-genotype analysis of the autosomal recessive hereditary hearing loss caused by OTOA variations / 中华耳鼻咽喉头颈外科杂志

Objective: To analyze the phenotypic-genotypic characteristics of hereditary deafness caused by OTOA gene variations. Methods: Family histories, clinical phenotypes and gene variations of six pedigrees were analyzed, which were diagnosed with hearing loss caused by OTOA gene variations at the PLA General Hospital from September 2015 to January 2022. The sequence variations were verified by Sanger sequencing and the copy number variations were validated by multiplex ligation-dependent probe amplification (MLPA) in the family members. Results: The hearing loss phenotype caused by OTOA variations ranged from mild to moderate in the low frequencies, and from moderate to severe in the high frequencies in the probands, which came from six sporadic pedigrees, among which a proband was diagnosed as congenital deafness and five were diagnosed as postlingual deafness. One proband carried homozygous variations and five probands carried compound heterozygous variations in OTOA gene. Nine pathogenic variations (six copy number variations, two deletion variations and one missense variation) and two variations with uncertain significance in OTOA were identified in total, including six copy number variations and five single nucleotide variants, and three of the five single nucleotide variants were firstly reported [c.1265G>T(p.Gly422Val),c.1534delG(p.Ala513Leufs*11) and c.3292C>T(p.Gln1098fs*)]. Conclusions: OTOA gene variations can lead to autosomal recessive nonsyndromic hearing loss. In this study, the hearing loss caused by OTOA defects mostly presents as bilateral, symmetrical, and postlingual, and that of a few presents as congenital. The pathogenic variations of OTOA gene are mainly copy number variations followed by deletion variations and missense variations.

Clinical features and genetic analysis of a child with EAST/SeSAME syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a EAST/SeSAME syndrome child featuring epilepsy, ataxia, sensorineural deafness and intellectual disability.@*METHODS@#A child with EAST/SeSAME syndrome who had presented at the Third Affiliated Hospital of Zhengzhou University in January 2021 was selected as the study object. Peripheral blood samples of the child and her parents were collected and subjected to whole exome sequencing. Candidate variants were verified by Sanger sequencing.@*RESULTS@#Genetic testing revealed that the child has harbored compound heterozygous variants of the KCNJ10 gene, namely c.557T>C (p.Val186Ala) and c.386T>A (p.Ile129Asn), which were inherited from her mother and father, respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted as likely pathogenic (PM1+PM2_Supporting+PP3+PP4; PM1+PM2_Supporting+PM3+PP3+PP4).@*CONCLUSION@#The patient was diagnosed with EAST/SeSAME syndrome due to the compound heterozygous variants of the KCNJ10 gene.

Analysis of clinical phenotype and genetic variants among four Chinese pedigrees affected with Waardenburg syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for four Chinese pedigrees affected with Waardenburg syndrome (WS).@*METHODS@#Four WS probands and their pedigree members who had presented at the First Affiliated Hospital of Zhengzhou University between July 2021 and March 2022 were selected as the study subjects. Proband 1, a 2-year-and-11-month female, had blurred speech for over 2 years. Proband 2, a 10-year-old female, had bilateral hearing loss for 8 years. Proband 3, a 28-year-old male, had right side hearing loss for over 10 years. Proband 4, a 2-year-old male, had left side hearing loss for one year. Clinical data of the four probands and their pedigree members were collected, and auxiliary examinations were carried out. Genomic DNA was extracted from peripheral blood samples and subjected to whole exome sequencing. Candidate variants were verified by Sanger sequencing.@*RESULTS@#Proband 1, with profound bilateral sensorineural hearing loss, blue iris and dystopia canthorum, was found to have harbored a heterozygous c.667C>T (p.Arg223Ter) nonsense variant of the PAX3 gene, which was inherited from her father. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PM2_Supporting+PP4), and the proband was diagnosed with WS type I. Proband 2, with moderate sensorineural hearing loss on the right side and severe sensorineural hearing loss on the left side, has harbored a heterozygous frameshifting c.1018_1022del (p.Val340SerfsTer60) variant of the SOX10 gene. Neither of her parents has harbored the same variant. Based on the ACMG guidelines, it was classified as pathogenic (PVS1+PM2_Supporting+PP4+PM6), and the proband was diagnosed with WS type II. Proband 3, with profound sensorineural hearing loss on the right side, has harbored a heterozygous c.23delC (p.Ser8TrpfsTer5) frameshifting variant of the SOX10 gene. Based on the ACMG guidelines, it was classified as pathogenic (PVS1+PM2_Supporting+PP4), and the proband was diagnosed with WS type II. Proband 4, with profound sensorineural hearing loss on the left side, has harbored a heterozygous c.7G>T (p.Glu3Ter) nonsense variant of the MITF gene which was inherited from his mother. Based on the ACMG guidelines, the variant was classified as pathogenic (PVS1+PM2_Supporting+PP4), and the proband was diagnosed with WS type II.@*CONCLUSION@#By genetic testing, the four probands were all diagnosed with WS. Above finding has facilitated molecular diagnosis and genetic counseling for their pedigrees.

A prospective study of genetic screening of 2 060 neonates by high-throughput sequencing / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of genetic screening by high-throughput sequencing (HTS) for the early diagnosis of neonatal diseases.@*METHODS@#A total of 2 060 neonates born at Ningbo Women and Children's Hospital from March to September 2021 were selected as the study subjects. All neonates had undergone conventional tandem mass spectrometry metabolite analysis and fluorescent immunoassay analysis. HTS was carried out to detect the definite pathogenic variant sites with high-frequency of 135 disease-related genes. Candidate variants were verified by Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA).@*RESULTS@#Among the 2 060 newborns, 31 were diagnosed with genetic diseases, 557 were found to be carriers, and 1 472 were negative. Among the 31 neonates, 5 had G6PD, 19 had hereditary non-syndromic deafness due to variants of GJB2, GJB3 and MT-RNR1 genes, 2 had PAH gene variants, 1 had GAA gene variants, 1 had SMN1 gene variants, 2 had MTTL1 gene variants, and 1 had GH1 gene variants. Clinically, 1 child had Spinal muscular atrophy (SMA), 1 had Glycogen storage disease II, 2 had congenital deafness, and 5 had G6PD deficiency. One mother was diagnosed with SMA. No patient was detected by conventional tandem mass spectrometry. Conventional fluorescence immunoassay had revealed 5 cases of G6PD deficiency (all positive by genetic screening) and 2 cases of hypothyroidism (identified as carriers). The most common variants identified in this region have involved DUOX2 (3.93%), ATP7B (2.48%), SLC26A4 (2.38%), GJB2 (2.33%), PAH (2.09%) and SLC22A5 genes (2.09%).@*CONCLUSION@#Neonatal genetic screening has a wide range of detection and high detection rate, which can significantly improve the efficacy of newborn screening when combined with conventional screening and facilitate secondary prevention for the affected children, diagnosis of family members and genetic counseling for the carriers.

Analysis of SALL1 gene variant in a boy with Townes-Brocks syndrome without anal atresia / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child presented with renal failure and multi-cystic dysplastic kidney without anal atresia.@*METHODS@#Peripheral blood sample of the child and his parents were collected and subjected to whole exome sequencing. Candidate variant was verified by Sanger sequencing.@*RESULTS@#The 40-day-old infant had presented with vomiting brown matter in a 7 days neonate and was transferred for kidney failure. Clinical examination has discovered renal failure, polycystic renal dysplasia, congenital hypothyroidism, bilateral thumb polydactyly, sensorineural hearing loss and preauricular dermatophyte. Genetic testing revealed that he has harbored a previously unreported c.824delT, p.L275Yfs*10 frameshift variant of SALL1 gene, which was confirmed by Sanger sequencing as de novo.@*CONCLUSION@#The patient was diagnosed with Townes-Brocks syndrome due to the novel de novo variant of SALL1 gene. Townes-Brocks syndrome without anal atresia is rare. Above finding has also enriched the mutational spectrum of the SALL1 gene.

Clinical and genetic analysis of a newborn with hypoparathyroidism, sensorineural hearing loss, and renal dysplasia syndrome / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and genetic basis for a male neonate featuring hypoparathyroidism, sensorineural hearing loss, and renal dysplasia (HDR) syndrome.@*METHODS@#The child was subjected to genome-wide copy number variation (CNVs) analysis and whole exome sequencing (WES). Clinical data of the patient was analyzed. A literature review was also carried out.@*RESULTS@#The patient, a male neonate, had presented with peculiar facial appearance, simian crease and sacrococcygeal mass. Blood test revealed hypocalcemia, hypoparathyroidism. Hearing test suggested bilateral sensorineural deafness. Doppler ultrasound showed absence of right kidney. Copy number variation sequencing revealed a 12.71 Mb deletion at 10p15.3-p13 (chr10: 105 001_12 815 001) region. WES confirmed haploinsufficiency of the GATA3 gene. With supplement of calcium and vitamin D, the condition of the child has improved.@*CONCLUSION@#The deletion of 10p15.3p13 probably underlay the HDR syndrome in this patient.

Severe polyhydramnios as neonatal presentation of Bartter's syndrome type IV / Polihidrâmnios grave como manifestação neonatal da síndrome de Bartter tipo IV

Abstract Introduction: Bartter's syndrome comprises a heterogeneous group of inherited salt-losing tubulopathies. There are two forms of clinical presentation: classical and neonatal, the most severe type. Types I and II account for most of the neonatal cases. Types III and V are usually less severe. Characteristically Bartter's syndrome type IV is a saltlosing nephropathy with mild to severe neonatal symptoms, with a specific feature - sensorineural deafness. Bartter's syndrome type IV is the least common of all recessive types of the disease. Description: the first reported case of a Portuguese child with neurosensorial deafness, polyuria, polydipsia and failure to thrive, born prematurely due to severe polyhydramnios, with the G47R mutation in the BSND gene that causes Bartter's syndrome type IV. Discussion: there are few published cases of BS type IV due to this mutation and those reported mostly have moderate clinical manifestations which begin later in life. The poor phenotype-genotype relationship combined with the rarity of this syndrome usually precludes an antenatal diagnosis. In the presence of a severe polyhydramnios case, with no fetal malformation detected, normal karyotype and after maternal disease exclusion, autosomal recessive diseases, including tubulopathies, should always be suspected.

Resumo Introdução: a síndrome de Bartter inclui um grupo heterogéneo de tubulopatias hereditárias perdedoras de sal. Existem duas formas de apresentação clínica: clássica e neonatal, a forma mais grave. Os tipo I e II representam a maioria dos casos neonatais. Os tipos III e V são geralmente menos graves. Caracteristicamente, a síndrome de Bartter tipo IV é uma nefropatia perdedora de sal com sintomas neonatais ligeiros a graves, com um aspeto especí- fico - surdez neurossensorial. A síndrome de Bartter tipo IV é o tipo menos comum das formas recessivas da doença. Descrição: relatamos o primeiro caso de uma criança portuguesa, com surdez neurossensorial, poliúria, polidipsia e restrição de crescimento, nascida prematuramente devido a polihidrâmnios grave, homozigótica para a mutação G47R do gene BSND, responsável pela síndrome de Bartter tipo IV. Discussão: são raros os casos publicados sobre síndrome de Bartter tipo IV atribuída a esta mutação, e a maioria referem-se a diagnósticos mais tardios, com manifestações clínicas ligeiras. A fraca correlação fenótipo-genótipo combinada com a raridade desta síndrome tornam o diagnóstico pré-natal desafiante. Perante um caso de polihidrâmnios grave em um feto sem malformações aparentes, cariótipo normal e após exclusão de patologia materna, as doenças autossómicas recessivas, incluindo as tubulopatias, devem ser sempre consideradas.

Identification of novel pathogenic variants of TRIOBP gene in a pedigree affected with non-syndromic deafness / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree affected with non-syndromic hearing loss (NSHL).@*METHODS@#Commercialized gene chip was applied to detect common mutations associated with congenital deafness. Whole exome sequencing was carried out for patients for whom gene chip yielded a negative result. Candidate variants were verified by Sanger sequencing.@*RESULTS@#Two patients from the pedigree were discovered to carry compound heterozygous variants of the TRIOBP gene, namely c.3299C>A and c.5185-2A>G. Their parents had normal hearing and were both heterozygous carriers of the above variants. Both variants had co-segregated with the disease phenotype in the pedigree and were unreported previously.@*CONCLUSION@#Pathogenic variants of the TRIOBP gene comprise an important factor for NSHL. The novel c.5185-2A>G and c.3299C>A variants discovered in this study have enriched the mutational spectrum of the TRIOBP gene and enabled molecular diagnosis and genetic counseling for the family.

Clinical and molecular genetic analysis of a case of MEGDEL syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and genetic characteristics of a child with MEGDEL syndrome.@*METHODS@#Clinical data of the child was reviewed. Peripheral blood samples of the child and his parents were collected. Mitochondrial genome and the whole exome of the child were analyzed by next-generation sequencing. Candidate variants and its origin were verified by Sanger sequencing and fluorescence quantitative PCR.@*RESULTS@#The patient, a 2-year-and-6-month-old male, has featured hypoglycemia, mental and motor retardation with regression. Cranial MRI showed bilateral putamen damage suggestive of Leigh syndrome. Testing of urine organic acid indicated that the level of 3-methylpentenoic acid was slightly increased. Whole exome sequencing revealed that the child has harbored heterozygous deletion of exons 6 to 17 and c.307A>T nonsense variant of the SERAC1 gene, which were respectively inherited from his parents who were asymptomatic. Treatment with Levocarnitine, vitamin B1, vitamin B2, coenzyme Q10, baclofen and glucuronolactone resulted in improvement of sleep and mental state.@*CONCLUSION@#A case of MEGDEL syndrome without deafness was diagnosed. Discovery of the nonsense mutation and large fragment deletion have enriched the spectrum of SERAC1 gene variants.

Analysis of DFNA5 gene variant in a Chinese pedigree affected with late-onset non-syndromic hearing loss / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree affected with autosomal dominant late-onset non-syndromic hearing loss (NSHL).@*METHODS@#Clinical data of the pedigree were collected. Genomic DNA was extracted from peripheral blood samples of the proband and other family members. Trio whole exome sequencing was carried out for 19 396 genes to identify potential pathogenic variants. Sanger sequencing was carried out to verify the candidate variant in the pedigree.@*RESULTS@#The proband and his father were found to carry a c.1183+1delG p.? variant of the DFNA5 gene. The variant was confirmed to be co-segregating with the disease phenotype in the pedigree.@*CONCLUSION@#The c.1183+1delG p.? variant of the DFNA5 gene probably underlay the late onset NSHL in this pedigree. Above finding has enabled accurate genetic counseling for this pedigree.

Genetic testing of a Chinese pedigree affected with non-syndromic autosomal dominant deafness 15 / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a Chinese pedigree affected with progressive non-syndromic sensorineural hearing loss.@*METHODS@#High-throughput DNA sequencing was carried out to analyze 415 genes associated with hereditary deafness in the proband. Sanger sequencing was carried out to verify the suspected variants among her family members.@*RESULTS@#The proband was found to carry a heterozygous c.842T>A (p.Ile281Asn) variant of the POU4F3 gene. The same variant was found among all other patients from the pedigree including the proband's mother, brother, aunt and maternal grandfather, but not among those with normal hearing. Based on the standards and guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology, the c.842T>A(p.Ile281Asn) variant of the POU4F3 gene was predicted as likely pathogenic (PM2+PM5+PP1+PP3+PP4).@*CONCLUSION@#A Chinese pedigree affected by a rare type autosomal dominant deafness-15 (DFNA15) due to a novel c.842T>A (p.Ile281Asn) variant of the POU4F3 gene was identified. The result has facilitated genetic counseling and risk assessment for the pedigree.

Molecular study of hearing loss in Minas Gerais, Brazil / Estudo molecular da perda auditiva em Minas Gerais, Brasil

Abstract Introduction: Deafness is the most frequent sensory deficit in humans. Incidence is estimated at 4:1000 births in Brazil. Specific programs for clinical care of patients with hearing loss are still scarce in Brazil and the issue is an important public health problem. Objective: To determine the frequency of 35delG and D13S1830 mutations in GJB2 and GJB6 genes respectively in patients with non-syndromic sensorineural hearing loss from Minas Gerais, Brazil. Methods: This research involved 53 individuals, who were assessed by a questionnaire for predicting the possibility of non-syndromic deafness and for data collecting. Samples were tested for the presence of the 35delG mutation in GJB2 gene and D13S1830 in GJB6 gene by polymerase chain reaction and restriction enzyme digestion. Results: Epidemiological research has shown that the majority of the subjects are unaware of the etiology and the pathogenesis of hearing loss. In 9 patients (16.98%), 35delG mutation was found in heterozygosis and the allele frequency was estimate to be around 8.5%. Although 9.61% of the patients reported having some degree of consanguinity between the parents and 12.08% reported other cases of deafness in their families, this mutation was not found in homozygosis. The D13S1830 mutation was not found in this study. Conclusion: This research describes for the first time the frequency of the 35delG and D13S1830 mutation in hearing-impaired individuals from Minas Gerais, Brazil, and the collected data reinforce the need for further studies in this population due to heterogeneity of hearing loss.

Resumo Introdução: A surdez é o déficit sensorial mais frequente em humanos. Estima-se que a incidência seja de 4:1.000 nascimentos no Brasil. Programas específicos para atendimento clínico de pacientes com perda auditiva são escassos no Brasil e a questão é um importante problema de saúde pública. Objetivo: Determinar a frequência das mutações 35delG no gene GJB2 e D13S1830 no GJB6 em pacientes deficientes auditivos de origem neurossensorial e não sindrômica de Minas Gerais, Brasil. Método: A pesquisa envolveu 53 indivíduos selecionados por meio de questionário o qual avaliou a possibilidade de surdez não sindrômica entre outros dados. As amostras foram testadas quanto à presença da mutação 35delG no gene GJB2 e D13S1830 no gene GJB6 por reação em cadeia da polimerase e digestão com enzima de restrição. Resultados: A pesquisa epidemiológica mostrou que a maioria dos indivíduos desconhece a etiologia da perda auditiva. Em 9 pacientes (16,98%), a mutação 35delG foi encontrada em heterozigose e a frequência alélica foi estimada em 8,5%. Embora 9,61% das pessoas tenham relatado algum grau de consanguinidade entre os pais e 12,08% relatassem outros casos de surdez em suas famílias, essa mutação não foi encontrada em homozigose. A mutação D13S1830 não foi encontrada neste estudo. Conclusão: Este trabalho descreve pela primeira vez a frequência da mutação 35delG e D13S1830 em deficientes auditivos de Minas Gerais, Brasil, e os dados coletados reforçam a necessidade de mais estudos nessa população devido à heterogeneidade da perda auditiva.

Association of glutamate metabotropic receptor polymorphisms and sensorineural hearing loss in adults of different age groups / Associação entre polimorfismos do gene do receptor metabotrópico de glutamato 7 e perda auditiva neurossensorial em adultos de diferentes faixas etárias

Abstract Introduction: Sensorineural hearing loss is a common challenge all over the world, including a section of the young population. While there have been many published reports associating glutamate metabotropic receptor 7 with sensorineural hearing loss, there is no report, till date, about the association of glutamate metabotropic receptor 7 polymorphisms with sensorineural hearing loss at different ages. Objective: To test the association between the single nucleotide polymorphisms rs11928865 and rs11920109 of the glutamate metabotropic receptor 7 with sensorineural hearing loss in adults of different age groups. Methods: A total of 1661 subjects were studied. The individuals aged between 30 and 50, and between 51 and 70 years with sensorineural hearing loss comprised group A and group B, respectively. Individuals aged between 30 and 50; and between 51 and 70 years without hearing loss comprised control groups C and D, respectively. The MassARRAY method was used to analyze the genotypes. Results: The difference in genotypes for the glutamate metabotropic receptor 7 rs11928865 single nucleotide polymorphism between patients in the groups B and D was statistically significant (p = 0.018). The distribution frequencies of genotypes in patients that were aged between 30 and 50 years were not significantly different. The difference in genotypes for the rs11920109 single nucleotide polymorphism between the sensorineural hearing loss groups and control groups showed no statistical significance. Conclusion: The rs11928865 single nucleotide polymorphism was associated with the susceptibility to hearing loss in patients in group B but not with those in group A.

Resumo Introdução: A perda auditiva neurossensorial é um desafio comum no mundo todo, inclui uma parte da população jovem. Embora haja muitos relatos que associem o gene do receptor metabotrópico de glutamato 7 com perda auditiva neurossensorial, não há relato, até a presente data, sobre a associação de polimorfismos do receptor metabotrópico de glutamato 7 com perda auditiva neurossensorial em diferentes faixas etárias. Objetivo: Testar a associação entre os polimorfismos de nucleotídeo único, rs11928865 e rs11920109 do receptor metabotrópico de glutamato 7 e perda auditiva neurossensorial em adultos de diferentes faixas etárias. Método: Um total de 1661 indivíduos foram estudados. Os indivíduos com idade entre 30 e 50 anos e entre 51 e 70 anos com perda auditiva neurossensorial constituíram o grupo A e o grupo B, respectivamente. Indivíduos com idade entre 30 e 50 anos; e entre 51 e 70 anos sem perda auditiva foram os grupos controle C e D, respectivamente. O método MassARRAY foi utilizado para analisar os genótipos. Resultados: A diferença nos genótipos para o polimorfismo de nucleotídeo único rs11928865 do gene receptor metabotrópico de glutamato 7 entre os pacientes dos Grupos B e D foi estatisticamente significante (p = 0,018). As frequências de distribuição dos genótipos nos pacientes entre 30 e 50 anos não foram significantemente diferentes. A diferença nos genótipos para o polimorfismo de nucleotídeo único rs11920109 entre os grupos com perda auditiva neurossensorial e os grupos controle não mostrou significância estatística. Conclusão: O polimorfismo de nucleotídeo único rs11928865 foi associado à suscetibilidade para perda auditiva em pacientes do grupo B, mas não àqueles do grupo A.

Frequency of GJB2 mutations in patients with nonsyndromic hearing loss from an ethnically characterized Brazilian population / Frequência de mutações de GJB2 em pacientes com perda auditiva não sindrômica em uma população brasileira etnicamente caracterizada

Abstract Introduction: In different parts of the world, mutations in the GJB2 gene are associated with nonsyndromic hearing loss, and the homozygous 35delG mutation (p.Gly12Valfs*2) is a major cause of hereditary hearing loss. However, the 35delG mutation is not equally prevalent across ethnicities, making it important to study other mutations, especially in multiethnic countries such as Brazil. Objective: This study aimed to identify different mutations in the GJB2 gene in patients with severe to profound nonsyndromic sensorineural hearing loss of putative genetic origin, and who were negative or heterozygote for the 35delG mutation. Methods: Observational study that analyzed 100 ethnically characterized Brazilian patients with nonsyndromic severe to profound sensorineural hearing loss, who were negative or heterozygote for the 35delG mutation. GJB2 mutations were detected by DNA-based sequencing in this population. Participants' ethnicities were identified as Latin European, Non-Latin European, Jewish, Native, Turkish, Afro-American, Asian and Others. Results: Sixteen participants were heterozygote for the 35delG mutation; 14 participants, including three 35delG heterozygote's, had nine different alterations in the GJB2 gene. One variant, p.Ser199Glnfs*9, detected in two participants, was previously unreported. Three variants were pathogenic (p.Trp172*, p.Val167Met, and p.Arg75Trp), two were non-pathogenic (p.Val27Ile and p.Ile196Thr), and three variants were indeterminate (p.Met34Thr, p.Arg127Leu, and p.Lys168Arg). Three cases of compound heterozygosity were detected: p.[(Gly12Valfs*2)];[(Trp172*)], p.[(Gly12Valfs*2)](;)[(Met34Thr)], and p.[(Gly12Valfs*2)(;)[(Ser199Glnfs*9)]). Conclusion: This study detected previously unclassified variants and one case of previously unreported compound heterozygosity.

Resumo Introdução: Em diferentes partes do mundo, mutações do gene GJB2 estão associadas a perda auditiva não sindrômica e a mutação homozigótica 35delG (p.Gly12Valfs*2) é uma das principais causas de perda auditiva hereditária. No entanto, a mutação 35delG não é igualmente prevalente em todas as etnias, faz com que seja importante estudar outras mutações, especialmente em países multiétnicos, como o Brasil. Objetivo: Identificar diferentes mutações no gene GJB2 em pacientes com perda auditiva neurossensorial grave ou profunda não sindrômica de origem genética putativa e negativos ou heterozigotos para a mutação 35delG. Método: Estudo observacional que analisou 100 pacientes brasileiros caracterizados etnicamente, com perda auditiva neurossensorial grave ou profunda não sindrômica, negativos ou heterozigotos para a mutação 35delG. As mutações de GJB2 foram detectadas por sequenciamento baseado no DNA nessa população. As etnias dos participantes foram identificadas como latino-europeia, não latino-europeia, judaica, nativa, turca, negra, asiática e outras. Resultados: Dezesseis participantes eram heterozigotos para a mutação 35delG e 14, incluindo três heterozigotos para 35delG, apresentaram nove alterações no gene GJB2. Uma variante, p.Ser199Glnfs*9, detectada em dois participantes, não havia sido relatada anteriormente. Três variantes eram patogênicas (p.Trp172*, p.Val167Met, e p.Arg75Trp), duas não patogênicas (p.Val27Ile e p.Ile196Thr) e três indeterminadas (p.Met34Thr, p.Arg127Leu, e p.Lys168Arg). Três casos de heterozigosidade composta foram detectados: p.[(Gly12Valfs*2)];[(Trp172*)], p.[(Gly12Valfs*2)](;)[(Met34Thr)], e p.[(Gly12Valfs*2)(;)[(Ser199Glnfs*9)]). Conclusão: Este estudo detectou variantes não classificadas anteriormente e um caso de heterozigosidade composta ainda não relatada.

Vohwinkel syndrome: ichthyosiform variant in a family

Abstract: Vohwinkel syndrome belongs to the group of hereditary palmoplantar keratoderma, having an autosomal dominant inheritance. In this report, the authors present a case of a four-year-old boy with diffuse scaling over his entire body and transgredient palmoplantar hyperkeratosis with some fissured areas. Family evaluation revealed that his mother and other family members were affected. Based on his clinical findings and on family history, the diagnosis of the ichthyotic Vohwinkel syndrome subtype, characterized by generalized ichthyosis and palmoplantar hyperkeratosis, was established.

Trombocitopenia hereditaria relacionada a gen MYH-9: primera familia reportada en Chile con diagnóstico molecular: caso clínico / Hereditary thrombocytopenia associated with a mutation in the MYH-9 gene: report of one case

We report a 51-year-old female who had a first episode of thrombocytopenia at 23 years of age during a pregnancy. At the age of fifty, a hysterectomy was indicated due to a metrorrhagia: a platelet count of 21,000/ul was detected. She was treated with eltrombopag with a good response. The family history of the patient revealed the presence of thrombocytopenia in several family members. Suspecting a hereditary thrombocytopenia, a genetic study revealed a mutation in the MYH-9 gene. This mutation can be suspected when there is a family history of thrombocytopenia with autosomal dominant inheritance, macrothrombocytopenia and in this particular case, due to the response to thrombopoietin receptor agonist, eltrombopag.

Hipoacusia neurosensorial no sindrómica: caracterización molecular, desempeño auditivo y tratamiento en pacientes con mutaciones en las conexinas 26 y 30 / Non-syndromic sensorineural hearing loss: molecular characterization, auditory performance, and treatment in patients with connexin 26 and 30 mutations

La hipoacusia congénita o de aparición temprana es un trastorno sensorial muy frecuente en niños. Las causas son diversas, pueden intervenir factores genéticos y/o ambientales. El 80% de la sordera hereditaria es no sindrómica y de herencia autosómica recesiva. Hasta un 50% de estos casos se deben a mutaciones en el locus DFNB1 donde están localizados los genes GJB2 y GJB6, que codifican las conexinas 26 y 30, dos proteínas que se expresan predominantemente en la cóclea. Se han reportado más de 100 mutaciones en el gen GJB2, con una mutación muy frecuente, 35delG, que representa hasta un 85% de los alelos mutados. Una deleción en el gen GJB6, (delGJB6-D13S1830), surge como la segunda mutación más frecuente. La hipoacusia debida a mutaciones en estos genes es de inicio prelocutivo, con un grado de severidad que varía de moderado a profundo, existiendo casos leves en menor proporción, con variaciones inter e intrafamiliares. Es generalmente estable, bilateral, y afecta a todas las frecuencias. El conocimiento de las causas genéticas de la hipoacusia ha permitido contar con nuevas herramientas para el diagnóstico, y como consecuencia, se ha optimizado el asesoramiento genético y facilitado el diagnóstico precoz de los pacientes, incluso en el período prenatal. La detección precoz tiene un impacto inmediato en la implementación de terapias que permiten una estimulación auditiva temprana. En esta revisión se describe el papel de las conexinas en la fisiología auditiva, así como también las características moleculares y audiológicas y el desempeño auditivo con audífonos e implante coclear en pacientes que presentan mutaciones en las conexinas 26 y 30.

Congenital or early appearing hearing loss is a very common sensory disorder in children. The causes for the disorder are diverse and genetic as well as environmental factors may be involved. Overall, 80% of the hereditary deafness is non-syndromic and of autosomal recessive inheritance. Up to 50% of the cases are associated with mutations in the DFNB1 locus that contains the GJB2 and the GJB6 genes encoding connexins 26 and 30, two proteins that are predominantly expressed in the cochlea. More than 100 mutations of the GJB2 have been reported. The 35delG is a common mutation accounting for up to 85% of the mutated alleles. A deletion in the GJB6 gene, (delGJB6-D13S1830), is the second most frequent mutation found. Hearing loss due to mutations in these genes has an onset before speech develops and degree of severity varies from moderate to severe, with a lower incidence of mild cases and inter- and intrafamily variations. The condition is usually stable, bilateral, and affecting all frequencies. Increased knowledge on the genetic causes of hearing loss has allowed for the development of new diagnostic tools and consequently, improvement of genetic counseling and early, even prenatal, diagnosis. Early detection has an immediate impact with implementation of early auditory stimulation therapies. In this review the role of connexins in auditory physiology described, as well as molecular and audiological features and auditory performance with hearing aids and cochlear implants in patients with connexins 26 and 30 mutations.

Síndrome de anemia megaloblástica sensible a la tiamina de aparición en la niñez, con mutación en el genSLC19A2: caso clínico / Infantile-onset thiamine responsive megaloblastic anemia syndrome with SLC19A2 mutation: a case report

Antecedentes. El síndrome de anemia megaloblástica sensible a la tiamina (TRMA, por sus siglas en inglés), también conocido como síndrome de Rogers, se caracteriza por presentar anemia megaloblástica, hipoacusia neurosensorial y diabetes mellitus. Las alteraciones en el transporte de la tiamina hacia las células se deben a mutaciones homocigotas o heterocigotas compuestas en el gen SLC19A2. Presentación de un caso. Presentamos el caso de una niña que manifestaba sordera neurosensorial tratada con una prótesis auditiva, diabetes con necesidad de insulina y anemia macrocítica, tratada con tiamina (100 mg/día). El nivel de hemoglobina mejoró hasta alcanzar 12,1 g/dl después de aumentar la dosis terapéutica de tiamina hasta 200 mg/día. Conclusión. Se debe evaluar a los pacientes con TRMA para detectar anemia megaloblástica, hipoacusia neurosensorial y diabetes mellitus. Se les debe dar seguimiento para determinar la respuesta de la enfermedad hematológica y de la diabetes después de la terapia con tiamina. La dosis terapéutica de tiamina puede aumentarse según la respuesta clínica. Debe proporcionarse asesoramiento genético.

Background. Thiamine-responsive megaloblastic anemia syndrome (TRMA), also known as Rogers syndrome, is characterized by megaloblastic anemia, sensorineural hearing loss, and diabetes mellitus. Disturbances of the thiamine transport into the cells results from homozygous or compound heterozygous mutations in the SLC19A2 gene. Case presentation. We report a girl which presented with sensorineural deafness treated with a hearing prosthesis, insulin requiring diabetes, macrocytic anemia, treated with thiamine (100 mg/day). Hemoglobin level improved to 12.1 g/dl after dose of thiamine therapy increased up to 200 mg/day. Conclusion. Patients with TRMA must be evaluated for megaloblastic anemia, sensorineural hearing loss, and diabetes mellitus. They must be followed for response of hematologic and diabetic after thiamine therapy. It should be kept in mind that dose of thiamine therapy may be increased according to the clinical response. Genetic counseling should be given.

Evaluation of electrocardiographic parameters in patients with hearing loss genotyped for the connexin 26 gene (GJB2) mutations / Avaliação dos parâmetros eletrocardiográficos em pacientes com perda auditiva genotipada para mutações do gene conexina 26 (GJB2)

Abstract Introduction: Several studies have associated congenital sensorineural hearing loss in children with prolongation of the cardiac parameter QTc. The cause of this association is unknown. At the same time, mutations in GJB2, which encodes connexin 26, are the most common cause of congenital hearing impairment. Objective: To compare electrocardiographic parameters (PR interval, QRS complex, and QTc interval) in patients with hearing loss who were tested for mutations in GJB2 and GJB6 to investigate whether these mutations affect electrical activity of the heart. Methods: 346 patients (176 males, 170 females) with sensorineural hearing loss of 30 dB HL or more, aged 21.8 ± 19.9 years (including 147 children <14 years), underwent both genetic study for GJB2 and GJB6 mutations and electrocardiography. Results: Mutations in GJB2, including homozygotes and heterozygotes, were found in 112 (32%) patients. There were no significant differences in ECG parameters between groups of patients with and without mutations in GJB2. No differences were observed either in men (mean PR with mutation: 155 ± 16.6 vs. 153.6 ± 30.1 without; QRS: 99.9 ± 9.9 vs. 101.1 ± 15.4; QTc: 414.9 ± 29.9 vs. 412.4 ± 25.7) or women (mean PR with: 148.7 ± 21 vs. 143.8 ± 22.8 without; QRS: 94.8 ± 7.6 vs. 92.9 ± 9.6; QTc: 416.8 ± 20.6 vs. 424.9 ± 22.8). In similar fashion, we did we find any significant differences between groups of children with and without GJB2 mutations (mean PR with: 126.3 ± 19.6 vs. 127 ± 19.7 without; QRS: 80.7 ± 9.5 vs. 79.4 ± 11.6; QTc: 419.7 ± 23.5 vs. 419.8 ± 24.8). Conclusion: No association was found between the presence of GJB2 mutations encoding connexin 26 in patients with hearing loss and their ECG parameters (PR, QRS, QTc).

Resumo Introdução: Vários estudos têm associado a perda auditiva neurossensorial congênita em crianças ao prolongamento do parâmetro cardíaco QTc. A causa dessa associação é desconhecida. Ao mesmo tempo, as mutações no GJB2, que codifica a conexina 26, são a causa mais comum de deficiência auditiva congênita. Objetivo: Comparar parâmetros eletrocardiográficos (intervalo PR, complexos QRS e intervalo QTc) em pacientes com perda auditiva que foram testados para mutações no GJB2 e GJB6 para investigar se essas mutações afetam a atividade elétrica do coração. Método: Foram submetidos a estudo genético para mutações de GJB2 e GJB6 e eletrocardiograma 346 pacientes (176 homens, 170 mulheres) com perda auditiva neurossensorial de 30 dB ou mais, com média de 21,8 ± 19,9 anos (incluindo 147 crianças <14 anos). Resultados: Mutações no GJB2, inclusive homozigóticos e heterozigóticos, foram encontradas em 112 (32%) pacientes. Não houve diferenças significativas nos parâmetros de ECG entre grupos de pacientes com e sem mutações no GJB2. Não foram observadas diferenças em homens (PR médio com mutação: 155 ± 16,6 vs. 153,6 ± 30,1 sem mutação; QRS: 99,9 ± 9,9 vs. 101,1 ± 15,4; QTc: 414,9 ± 29,9 vs. 412,4 ± 25,7) nem em mulheres (PR médio com: 148,7 ± 21 vs. 143,8 ± 22,8, sem; QRS: 94,8 ± 7,6 vs. 92,9 ± 9,6; QTc: 416,8 ± 20,6 vs. 424,9 ± 22,8). Da mesma forma, encontramos diferenças significativas entre os grupos de crianças com e sem mutações de GJB2 (PR médio com: 126,3 ± 19,6 vs. 127 ± 19,7, sem; QRS: 80,7 ± 9,5 vs. 79,4 ± 11,6; QTc: 419,7 ± 23,5 vs. 419,8 ± 24,8). Conclusão: Não foi encontrada associação entre a presença de mutações de GJB2 que codificam conexina 26 em pacientes com perda auditiva e seus parâmetros de ECG (PR, QRS, QTc).