Research on THRβ gene mutation in a patient with thyroid hormone resistance syndrome using whole-exome sequencing / 中华内分泌代谢杂志

Objective:To assess clinical and genetic features in a patient with thyroid hormone resistance syndrome(RTH) and explore the pathogenic mechanism.Methods:The clinical data of the proband was collected. The genomic DNA was extracted from peripheral blood samples of the patients. The pathogenic variant was identified using whole-exome sequencing and confirmed by Sanger sequencing. Then the function of the mutation sites was detected by bioinformatics.Results:The patient presented with chest distress, palpitation, and persistent atrial fibrillation, along with elevated levels of serum free triiodothyronine(FT 3), free thyroxine(FT 4), and thyroid stimulating hormone(TSH), which suggested RTH clinically. The genetic analysis identified a heterozygous mutant of THRβ(c.1313G>A) gene at exon 8, which was a missense mutation causing the substitution of arginine to histidine at 438 position of the protein(p.R438H). Its inheritance pattern was unknown. This mutation was considered as a new one that had not been reported. Conclusion:A novel pathogenic THRβ gene mutation was found in the patient with RTH, which might be the cause of this disease. This variant c. 1313G>A is located in the ligand binding domain of THRβ, which might result in low protein activity.

Analysis of combined screening results for hearing and deafness in 842 newborns in Dalian / 中国医师进修杂志

Objective:To analyze the results of the joint screening of newborn hearing and deafness genes in Dalian to provide a reference for the prevention and control of hereditary deafness.Methods:Eight hundred and forty-two neonates born in Dalian Women and Children′s Medical Group from January 1, 2022 to May 30, 2022 were screened retrospectively, using AABR (automatic brainstem evoked potential). And 20 mutation sites of common genetic deafness 4 genes , including GJB2, GJB3, SLC26A4 (PDS) and mitochondrial genes associated with drug-induced deafness (MT-RNRI)(12SrRNA), were detected by high-throughput sequencing.Results:Among the 842 newborns, 840 passed hearing screening (99.8%); 36 cases (4.3%) passed the hearing screening but not the hearing loss gene screening; 804 cases passed through the both screening (95.5%); 2 cases (0.24%) failed in the both screening. 38 cases of deafness gene mutations were detected, with a total carrying rate of 4.51% (38/842). Among them, the carrying rates of heterozygous mutations in GJB2, GJB3, SLC26A4 (PDS), MT-RNRI (12SrRNA) were 1.90%, 0.24%, 1.30%, and 0.95%, respectively. The carrying rates of GJB2/GJB3 composite heterozygous mutations were 0.12%.Conclusions:The combined screening of neonatal hearing and deafness genes can reduce the missed rate of hearing screening. The carrier rate of neonatal deafness gene in Dalian is 4.51%, with the highest GJB 2 carrier rate, followed by SLC26A4 (PDS) carrier rate.

Diagnostic Methods of Global Developmental Delay Caused by 10q24.3 Heterozygous Loss： A Case Discussion / 中山大学学报(医学科学版)

ObjectiveTo discuss the diagnostic methods of global developmental delay caused by 10q24.3 heterozygous loss. MethodsA retrospective analysis was conducted on the clinical data of one child with global developmental delay， and the results of low depth whole-genome copy number variation sequencing （CNVseq） and family whole exome sequencing （WES） of the child and his parents. ResultsThe patient was a 10-month-old male with developmental retardation in four areas， with some special features （ocular hypertelorism， strabismus， flat nose bridge， protruding forehead， cleft palate， high palatal arch， etc.） and hypotonia of limbs. The CNVseq and WES test showed that the patient had new 10q24.3 heterozygosis loss. Because this region contains the gene SUFU associated with basal cell nevus syndrome and the gene CNNM2 associated with hypomagnesemia， seizures， and mental retardation， and the gene TRIM8 associated of Focal segmental glomerulosclerosis with neurodevelopmental syndrome， we speculated that the cause of the disease in the child was highly related to the heterozygosity deletion of SUFU gene and CNNM2 gene and TRIM8 gene. ConclusionGenetic testing should be improved as soon as possible for children with global developmental delay and special facial manifestations， so as to make clear diagnosis and to judge prognosis.

La doble heterocigosis por la mutación común en el codón 39 (C>T) (ß0) y la deleción siciliana (δß0) 13.4 kb causa una beta-talasemia transfusión dependiente en dos pacientes costarricenses / (Double heterozygosity for the common mutation at codon 39 (C>T) (ß0) and the Sicilian (δß0) 13.4 kb deletion, causes transfusiondependent beta-thalassemia in two Costa Rican patients)

Las talasemias son desórdenes autosómicos recesivos de las cadenas de hemoglobina que poseen expresión clínica variable según el tipo de mutación o deleción. Presentamos el caso de dos jóvenes mujeres costarricenses no relacionadas entre sí y ambas diagnosticadas con la mutación común en el codón 39 (C>T) (β0) en combinación con la deleción siciliana (δβ0) 13.4 kb. La caracterización de doble heterocigota no había sido descrita antes en la literatura médica, y discutimos el significado de este genotipo que causa un defecto tipo β0 talasemia transfusión dependiente.

Thalassemia are autosomal recessive disorders of hemoglobin chains with variable clinical expression depending on the type of mutation or deletion present. We present the common codon 39(C>T) (β0) in combination with the δβ0 13.4 kb Sicilian deletion in two non-related young women from Costa Rica. We report the characterization of the compound heterozygous not previously described phenotype, and discuss the significance of this genotype combination with a transfusion dependent β0 defect Thalassemia.

DOUBLE HETEROZYGOSITY OF HBS AND HBD PUNJAB IN TWO SIBLINGS WITH COVID-19 INFECTION: A CASE REPORT

Introduction : HbD Punjab is also known as HbD Los Angeles was first described by Itano in 1951. In HbD point mutation in beta globin chain occurs . HbD associated with HbS in which one gene carries HbD while other gene carries HbS mutation . Infants are at increased risk of life threatening complications like severe anaemia , splenic sequestration , overwhelming septicaemia . Method: Two siblings one 9 year old male and other 4 year old male patients were presented with covid 19 infection in the hospital . Both were known caseof sickle cell disease . There blood samples were taken and cbc , retic and HPLC was done . Both were diagnosed as HbSD Heterozygosity by HPLC method .Their mother was a know case of sickle cell trait and father was known case of HbD Punjab trait. RESULT : In above study diagnosis of HbSD in both siblings was confirmed byHPLC. Since both their parents were carriers of sickle cell trait(mother) and HbD trait(father) . HbSD is a heterozygous state beta 121 glutamine residues stabilise the polymer and increases intracellular polymerization of HbS and increase sickling phenomenon .CONCLUSION : HbSD is a rare but very serious disorder with high prevalence in northern part of India . It is a genetically inherited disorder occurs when either of one parent is HbD trait and other one being HbS trait.

Differences in hormonal levels between heterozygous CYP21A2 pathogenic variant carriers, non-carriers, and females with non-classic congenital hyperplasia

ABSTRACT Objective: CYP21A2 mutation heterozygote carriers seem to have an increased risk of hyperandrogenism. However, the clinical relevance of the heterozygote carrier status and the reliability of hormonal testing in discriminating a carrier from a non-carrier are puzzling questions. We aimed to characterize a population of Portuguese females suspected of having non-classic congenital adrenal hyperplasia (NC-CAH) due to clinical and biochemical criteria and who have undergone CYP21A2 molecular analysis. Subjects and methods: Retrospectively, we have analyzed the clinical records of 131 females (32 girls aged 3-9 and 99 adolescents and premenopausal women aged 13-49) who underwent complete CYP21A2 molecular analysis due to suspicion of NC-CAH. We divided included participants into three groups according to the CYP21A2 molecular analysis: NC-CAH females (46), heterozygous carriers (49), and wild type (36). We then compared clinical signs and symptoms as well as biochemical and molecular data between carriers and NC-CAH individuals and between carriers and wild type females. We measured 17OHP by electrochemiluminescence immunoassay. Results: Clinical features were similar between groups. Heterozygous carriers presented higher basal and post-cosyntropin 17-hydroxyprogesterone (17OHP) than wild type individuals (p < 0.05) and lower basal and stimulated 17OHP levels than NC-CAH patients (p < 0.05). We discovered a considerable overlap between 17OHP levels among groups. The most common pathogenic variant we identified was p.Val282Leu. Conclusion: In this population of hyperandrogenic women and children, heterozygous carriers showed higher basal and stimulated 17OHP than non-carriers although normal basal and stimulated 17OHP responses do not exclude heterozygosity for CYP21A2 pathogenic variants. In this study, only the molecular analysis presented good sensitivity in identifying heterozygotes.

MODY11 induced by heterozygous mutations of a novel B lymphocyte kinase / 中华内分泌代谢杂志

To characterize the clinical and molecular features of a patient with maturity-onset diabetes of the young 11(MODY11) and literature review. The patient was a 30-year-old female with hyperglycemia for 2 years. Failure to thrivea, primary amenorrhea, intellectual impairment, and severe hyperlipidemia were present at the same time. A novel mutations of the B lymphocyte kinase gene(BLK) c. 1025C>T(p.A342V) was found in the patient. Literature review revealed that there were more than ten mutation sites in BLK-MODY11. Some of them had hyperglycemia, over weight or systemic lupus erythematosus. To date, the clinical characteristics of the patient, such as growth retardation, primary amenorrhea, and intellectual impairment have not been reported in MODY11. Our clinical report further expands the clinical presentations and variabilities of MODY11.

Analysis of two propositas with inherited hypodysfibrinogenemia / 中华检验医学杂志

Objective:To analyze the phenotype and genotype of two propositi with inherited hypodysfibrinogenaemia caused by compound heterozygous mutations, and investigate the molecular mechanism.Metheds:Two propositi and their family members(7 person in 3 generations and 10 person in 3 generations,respectively) were investigated. The activity of plasma fibrinogen (Fg:C) and thrombin time (TT) were analyzed by coagulation method, the antigen of plasma fibrinogen (Fg:Ag) was detected by immunoturbidimetry. All of the exons and flanking sequences of FGA,FGB,FGG of two propositi were amplified by PCR, followed by direct sequencing. The ClustalX-2, 1-win software was used to analyze the conservatism of mutated gene locus. PROVEAN and Mutation Taster were applied to analyze the pathogenicity of mutated amino acid. The changes of the protein spatial structure and intermolecular interaction were analyzed by Pymol.Results:Fg:C and Fg:Ag of proposita A and B were both significantly decreased (0.74 and 0.78 g/L, 0.96 and 0.94 g/L, respectively). Gene analysis revealed that proposita A and B both carried a heterozygous mutation c.2185G>A(p.AαGlu710Lys) in exon 6 of FGA. Furthermore, proposita A also carried a heterozygous mutation c.701G>T(p.γTrp208Leu) in exon 7 of FGG, and proposita B carried a heterozygous mutation c.1015A>C(p.γSer313Arg) in exon 8 of FGG. Phylogenetic analysis suggested that p.AαGlu710,p.γTrp208 and p.γSer313 were highly conserved among homologous species. All variants were predicted to be deleterious by two online bioinformatic softwares. The protein model analysis indicated that protein spatial structure and intermolecular hydrogen bonds were changed by these variants, which destroyed the stability of Fg.Conclusion:The compound heterozygous mutations of p.AαGlu710Lys and p.γTrp208Leu,p.AαGlu710Lys and p.γSer313Arg might account for the hypodysfibrinogenemia in two propositi.

Mutation analysis of the PNPLA1 gene in three families with congenital ichthyosiform erythroderma / 中华皮肤科杂志

Objective:To detect gene mutations in 3 Chinese families with congenital ichthyosiform erythroderma.Methods:Exome sequencing of peripheral blood DNA was performed for 3 probands clinically diagnosed with congenital ichthyosiform erythroderma by using a gene panel targeting hereditary skin diseases to identify mutation sites. Primers were designed according to the mutation sites for PCR amplification, and Sanger sequencing was performed to verify the mutations in probands and other family members in order to identify the cause of the disease.Results:The probands 1 and 2 presented with generalized skin dryness and scaling, and polygonal dark brown scales on the extensor aspect of the lower limbs; the proband 3 mainly presented with well-circumscribed erythema, papules and scales scattered on the trunk and extremities. All probands denied family history of similar diseases. Genetic testing showed that the proband 1 carried compound heterozygous mutations c.100G>A and c.377G>A in the PNPLA1 gene, which were inherited from her mother and father respectively; the proband 2 carried compound heterozygous mutations c.320T>A and c.434T>C in the PNPLA1 gene, which were inherited from her mother and father respectively; a homozygous mutation c.1300delG was identified in the PNPLA1 gene in the proband 3. The mutations co-segregated with the disease phenotypes in the two families with compound heterozygous mutations. Among the 5 identified mutations, the two missense mutations (c.377G>A and c.320T>A) were firstly reported.Conclusion:Biallelic mutations in the PNPLA1 gene are the causative mutations responsible for autosomal recessive congenital ichthyosis in the three probands, and the newly reported mutations expand the mutation spectrum in the disease.

Mutation analysis of the COL7A1 gene in 4 cases of recessive dystrophic epidermolysis bullosa / 中华皮肤科杂志

Objective:To analyze gene mutations in and clinical phenotypes of 4 children with recessive dystrophic epidermolysis bullosa (RDEB) .Methods:Clinical data were collected from 4 children with RDEB, and DNA was extracted from peripheral blood samples of the children and their parents. A multi-gene panel targeting congenital epidermolysis bullosa was used for high-throughput sequencing. After identification of causative gene mutations, Sanger sequencing was performed to bidirectionally verify the mutations in the patients and their parents.Results:Genetic testing showed 8 compound heterozygous mutations in the COL7A1 gene in the 4 cases. Case 1 was diagnosed with moderate generalized RDEB, and inherited a paternal mutation c.7828C>T and a maternal mutation c.448G> A; case 2 was also diagnosed with moderate generalized RDEB, and inherited a paternal mutation c.3625_3635del and a maternal mutation c.2726_2728del; case 3 was diagnosed with localized RDEB, carrying a paternal mutation c.682+1G>A and an allelic mutation c.5532+1G>A, but the mutation c.5532+1G>A was not identified in the DNA extracted from the parental peripheral blood samples; case 4 was diagnosed with severe generalized RDEB, and inherited a paternal mutation c.5196delC and a maternal mutation c.500_501insAGGG. Among these mutations, c.2726_2728del and c.5196delC had not been reported previously.Conclusions:All the 4 children with RDEB carried compound heterozygous mutations in the COL7A1 gene, which may be the cause of RDEB. The phenotypes of biallelic frameshift mutation carriers appearred more severe than those of carriers of compound heterozygous mutations composed of biallelic splice site, missense and nonsense, frameshift and amino acid deletion or insertion mutations.

A novel mutation in the ALOX12B gene in hereditary ichthyosis: pedigree analysis for a female collodion baby / 中华皮肤科杂志

Objective:To investigate pathogenic genes and inheritance patterns in 3 consecutive collodion babies in a family.Methods:The proband was diagnosed as a collodion baby due to extensive dry and chapped skin all over the body at birth. Phenotypes of the proband's parents were normal, but their first and second children presented with dry and chapped skin at birth and died a few days after birth. DNA was extracted from peripheral blood samples of the patient and her parents for whole-exome capture sequencing, and candidate mutations were verified by Sanger sequencing.Results:Compound heterozygous mutations in the ALOX12B gene were identified in the infant, including a missense mutation c.1405 C>T (p.R469w) inherited from her father and a frameshift mutation c.68_69insC (p.L24fs) inherited from her mother.Conclusions:The infant was diagnosed with hereditary ichthyosis, which was inherited in an autosomal recessive manner. The missense mutation c.1405 C>T and frameshift mutation c.68_69insC in the ALOX12B gene may contribute to the clinical phenotype of this infant, and the frameshift mutation had not been reported in China or other countries.

Clinical and genetic analysis of five patients with familial male-limited precocious puberty / 中华内分泌代谢杂志

Objective:To analyze the clinical and genetic characteristics of five patients with familial male-limited precocious puberty(FMPP).Methods:The clinical data, laboratory and imaging results of the five patients with FMPP were collected. Whole exome sequencing was carried out to identify the potential variants. Suspected variants were verified by Sanger sequencing of family numbers.Results:Of the five patients, four were children and one was an adult. All the four children presented to hospital with premature sexual development at age less than 4 years. Serum testosterone was elevated, luteinizing hormone(LH) and follicle stimulating hormone(FSH) basal values were at prepubertal levels, and gonadotropin-releasing hormone(GnRH) stimulation test suggested peripheral precocious puberty. Genetic analysis revealed the mutations of LHCGR genes in all the five patients. Patients 1, 2, 3, and 4 carried the same heterozygous mutation c. 1713G>C(p.M571I), and the patient 5 carried the c. 1741T>C(p.C581R)variation. The four children were treated with anti-androgen preparations and the third-generation aromatase inhibitors, all of which were effective.Conclusion:The c. 1713G>C mutation of LHCGR gene is a novel one which expands the mutation spectrum of LHCGR gene. Combined treatment with bicaluamide and the third generation aromatase inhibitors can improve clinical symptoms and delay epiphyseal closure in children with FMPP.

Novel Pathogenic Mutation of PNPLA1 Identified in Autosomal Recessive Congenital Ichthyosis: A Case Report / 中国医学科学杂志(英文版)

Autosomal recessive congenital ichthyosis (ARCI) is characterized by being born as collodion babies, hyperkeratosis, and skin scaling. We described a collodion baby at birth with mild ectropion, eclabium, and syndactyly. Whole exome sequencing showed a compound heterozygous variant c.[56C>A], p.(Ser19X) and c.[100G>A], p.(Ala34Thr) in the PNPLA1 gene [NM_001145717; exon 1]. The protein encoded by PNPLA1 acts as a unique transacylase that specifically transfers linoleic acid from triglyceride to ω-hydroxy fatty acid in ceramide, thus giving rise to ω-O-acylceramide, a particular class of sphingolipids that is essential for skin barrier function. The variant was located in the patatin core domain of PNPLA1 and resulted in a truncated protein which could disrupt the function of the protein. This case report highlights a novel compound heterozygous mutation in PNPLA1 identified in a Chinese child.

Characteristics and Clinical Implication of UGT1A1 Heterozygous Mutation in Tumor / 中国肺癌杂志

BACKGROUND@#The literature recommends that reduced dosage of CPT-11 should be applied in patients with UGT1A1 homozygous mutations, but the impact of UGT1A1 heterozygous mutations on the adverse reactions of CPT-11 is still not fully clear.@*METHODS@#A total of 107 patients with UGT1A1 heterozygous mutation or wild-type, who were treated with CPT-11 from January 2018 to September 2021 in Peking University Third Hospital, were retrospectively enrolled. The adverse reaction spectra of patients with UGT1A1*6 and UGT1A1*28 mutations were analyzed. Adverse reactions were evaluated according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) 5.0. The efficacy was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. The genotypes of UGT1A1*6 and UGT1A1*28 were detected by digital fluorescence molecular hybridization.@*RESULTS@#There were 43 patients with UGT1A1*6 heterozygous mutation, 26 patients with UGT1A1*28 heterozygous mutation, 8 patients with UGT1A1*6 and UGT1A1*28 double heterozygous mutations, 61 patients with heterozygous mutation at any gene locus of UGT1A1*6 and UGT1A1*28. Logistic regression analysis showed that the presence or absence of vomiting (P=0.013) and mucositis (P=0.005) was significantly correlated with heterozygous mutation of UGT1A1*28, and the severity of vomiting (P<0.001) and neutropenia (P=0.021) were significantly correlated with heterozygous mutation of UGT1A1*6. In colorectal cancer, UGT1A1*6 was significantly correlated to diarrhea (P=0.005), and the other adverse reactions spectrum was similar to that of the whole patient cohort, and efficacy and prognosis were similar between patients with different genotypes and patients treated with reduced CPT-11 dosage or not.@*CONCLUSIONS@#In clinical use, heterozygous mutations of UGT1A1*6 and UGT1A1*28 are related to the risk and severity of vomiting, diarrhea, neutropenia and mucositis in patients with Pan-tumor and colorectal cancer post CPT-11 therpy. In colorectal cancer, UGT1A1*6 is significantly related to diarrhea post CPT-11 use, efficacy and prognosis is not affected by various genotypes or CPT-11 dosage reduction.

Heterozygous living donor liver transplantation for pediatric maple syrup urine disease with new compound mutation of BCKDHB gene: a case report and literature review / 器官移植

Objective To evaluate the clinical efficacy of heterozygous living donor liver transplantation for pediatric maple syrup urine disease. Methods A 3-year-old boy was admitted to the hospital on July 5, 2017 due to maple syrup urine disease for half a year. The child presented with paroxysmal dysarthria and motor dysfunction of the lower limbs under fasting status for half a year, accompanied with obvious maple syrup urine odor and slow language development. No other growth abnormality or mental defects were observed. Serum branched chain amino acid (BCAA) assay detected that the level of leucine was 684 μmol/L and 559 μmol/L for the valine. The child was diagnosed with maple syrup urine disease type b based on gene detection combined with BCAA assay. Living donor liver transplantation from his biological father was performed. Postoperatively, routine immunosuppression, anti-virus, anti-infection therapies, maintenance of fluid, electrolyte, and acid-base balance and other necessary nutritional support were given. The dose of tacrolimus was adjusted according to biochemical parameters and cytochrome P450(CYP)3A5 genotype of the recipient. Glucocorticoid administration was terminated at approximately 6 months after operation. Results The liver function of the recipient was recovered to normal range at postoperative 1 month, and basically stabilized at 3 years after surgery. The amino acid level was decreased to normal level immediately after operation, and BCAA was continually declined after normal diet for postoperative 1 month. As of the submission date, the recipient grew well in a stable condition and achieved high quality of life. Conclusions Heterozygous living donor liver transplantation is a safe and effective treatment of maple syrup urine disease, which reduces the possibility of sudden acute metabolic events, significantly improves the quality of life of the recipient and provides a novel idea for surgical treatment of maple syrup urine disease.

Portador Heterozigoto Composto de Hipercolesterolemia Familiar Causada por Variantes no LDLR / Compound Heterozygous Familial Hypercholesterolemia Caused by LDLR Variants

Resumo A hipercolesterolemia familiar (HF) é uma doença genética causada por um defeito primário no gene que codifica o receptor da LDL. Mutações diferentes no mesmo gene caracterizam um heterozigoto composto, mas pouco se sabe sobre o fenótipo dos portadores. Portanto, neste estudo, descrevemos o rastreamento em cascata de uma família brasileira com essa característica. O caso-índice é um homem de 36 anos, com colesterol total (CT) de 360 mg/dL (9,3 mmol/L) e concentração de LDL-c de 259 mg/dL (6,7 mmol/L), além de xantomas de tendão de Aquiles, obesidade e pré-hipertensão. A genotipagem identificou as mutações 661G>A, 670G>A e 682G>A, no exon 4, e 919G>A, no exon 6. A mesma mutação no exon 4 foi observada no filho do caso-índice (7 anos), que também tem hipercolesterolemia e xantomas tendinosos, ao passo que a filha do caso-índice (9 anos) apresenta mutação no exon 6 e hiperlipidemia, sem xantomas. Em suma, este relato permite uma melhor compreensão acerca da base molecular da HF no Brasil, um país multirracial, onde é esperada uma população heterogênea.

Abstract Familial hypercholesterolemia (FH) is a genetic disease caused by a primary defect in the LDL-receptor gene. Distinct variants in the same gene characterize a compound heterozygote, but little is known about the phenotypes of the carriers. Therefore, herein, we describe the cascade screening of a Brazilian family with this characteristic. The index case, a 36-year-old male, had a total cholesterol level of 360 mg/dL (9.3 mmol/L) and LDL-c value of 259 mg/dL (6.7 mmol/L), in addition to Achilles tendon xanthomas, obesity and prehypertension. Genotyping identified the variants 661G>A, 670G>A, 682G>A in exon 4 and 919G>A in exon 6. The same variant in exon 4 was found in the index case's son (7-y), who also had hypercholesterolemia and xanthomas, while the index case's daughter (9-y) had the variant in exon 6 and hyperlipidemia, without xanthomas. In summary, this report allows for a better insight into the molecular basis of FH in Brazil, a multi-racial country where a heterogeneous population is expected.

Analysis of ARSA gene variant in an infant with late infantile metachromatic leukodystrophy / 中华医学遗传学杂志

Objective@#To detect pathogenic variant of ARSA gene in an infant with late infantile metachromatic leukodystrophy (MLD).@*Methods@#The male proband had an onset of walking dysfunction and seizure at 28 months. Arylsulfatase A activity of his peripheral blood leucocytes was 26.9 nmol/mg.17h, and cranial MRI showed wild symmetrical demyelination. With genomic DNA extracted from his peripheral blood sample, all coding exons and splicing sites of the ARSA gene were subjected to Sanger sequencing. PubMed Protein BLAST system was employed to analyze cross-species conservation of the mutant amino acid. Ucsf chimera software was used to analyze the impact of candidate variants on the secondary structure of the protein product. Impact of potential variants was also analyzed with software including PolyPhen-2, Mutation Taster, SIFT and PROVEAN. Whole-exome sequencing was carried out to identify additional variants which may explain the patient’s condition.@*Results@#The proband was found to harbor compound heterozygous variants of the ARSA gene [c.467G>A (p.Gly156Asp) and c. 960G>A (p.Trp320*)], neither of which was reported previously. As predicted by Ucsf chimera software, the c. 960G>A (p.Trp320*) variant may demolish important secondary structures including α-helix, β-strand and coil of the ARSA protein, causing serious damage to its structure and loss of function. The c. 467G>A (p.Gly156Asp) variant was predicted to be "probably damaging" by PolyPhen-2, Mutation Taster and SIFT software.@*Conclusion@#The patient’s condition may be attributed to the compound heterozygous c. 467G>A (p.Gly156Asp) and c. 960G>A (p.Trp320*) variants of the ARSA gene. Above results have facilitated genetic counseling and prenatal diagnosis for this family.

A Novel Heterozygous Missense Variant (c.667G>T;p.Gly223Cys) in USH1C That Interferes With Cadherin-Related 23 and Harmonin Interaction Causes Autosomal Dominant Nonsyndromic Hearing Loss

BACKGROUND: Pathogenic variants of USH1C, encoding a PDZ-domain-containing protein called harmonin, have been known to cause autosomal recessive syndromic or nonsyndromic hearing loss (NSHL). We identified a causative gene in a large Korean family with NSHL showing a typical pattern of autosomal dominant (AD) inheritance.METHODS: Exome sequencing was performed for five affected and three unaffected individuals in this family. Following identification of a candidate gene variant, segregation analysis and functional studies, including circular dichroism and biolayer interferometry experiments, were performed.RESULTS: A novel USH1C heterozygous missense variant (c.667G>T;p.Gly223Cys) was shown to segregate with the NSHL phenotype in this family. This variant affects an amino acid residue located in the highly conserved carboxylate-binding loop of the harmonin PDZ2 domain and is predicted to disturb the interaction with cadherin-related 23 (cdh23). The affinity of the variant PDZ2 domain for a biotinylated synthetic peptide containing the PDZ-binding motif of cdh23 was approximately 16-fold lower than that of the wild-type PDZ2 domain and that this inaccessibility of the binding site was caused by a conformational change in the variant PDZ2 domain.CONCLUSIONS: A heterozygous variant of USH1C that interferes with the interaction between cdh23 and harmonin causes novel AD-NSHL.

Co-occurrence of heterozygous mutations in COL1A1 and SERPINF1 in a high-risk pregnancy complicated by osteogenesis imperfecta

Mutations in several genes, including SERPRINF1 and COL1A1, have been associated with the development of osteogenesis imperfecta (OI). Here, we reported the co-occurrence of a rare heterozygous variant (c.167C>G p.Ala56Gly) in SERPRINF1 and a novel heterozygous mutation (c.1634G>A p.Gly545Asp) in COL1A1 in a foetus with a severe form of OI. Bioinformatics modelling revealed that the effect of the mutation on SPERINF1 is neutral. In contrast, the mutation in COL1A1 is deleterious. It is predicted to cause distortion of the α (1) chain of the type I collagen and results in structural instability of the protein. Therefore, a novel dominant variant of COL1A1 likely underlies the severe foetal pathology observed, although we do not exclude the possibility that the heterozygous mutations in SERPINF and COL1A1 may interact and co-ordinately cause pathogenesis. This novel COL1A1 mutation is recommended to be included in the diagnostic panels for OI.

Genetic analysis and clinical features of a pedigree affected with hereditary coagulation factor Ⅶ deficiency caused by compound heterozygotic mutations / 中华医学遗传学杂志

Objective@#To detect potential mutations of the coagulation factor Ⅶ (F7) gene in a pedigree affected with hereditary FⅦ deficiency and explore its molecular pathogenesis.@*Methods@#The FⅦ antigen (FⅦ∶Ag) was analyzed by an enzyme-linked immunosorbent assay (ELISA) method. Prothrombin time (PT), FⅦ activity (FⅦ∶C) and other coagulant parameters were quantified with an one-stage clotting assay. The F7 gene was amplified by PCR and sequenced. Mutational sites were confirmed by reverse sequencing. Impact of amino acid substitution was assessed using SIFT and PolyPhen-2 software. Structure of the mutant protein was analyzed using Swiss-pdb Viewer software based on the three-dimensional structure in the Protein Data Bank.@*Results@#The propositus had prolonged PT (36.3 s), with FⅦ∶C and FⅦ∶Ag significantly reduced to 2% and 44%, respectively. Her father, mother, younger sister and daughter had slightly prolonged PT and reduced FⅦ∶C (86%-120%). The FⅦ∶Ag of her father and younger sister were also reduced. DNA sequencing revealed that the propositus has carried compound heterozygous mutations (Lys341Glu and IVS6-1G>A) of the F7 gene. Her father and younger sister were heterozygous for the IVS6-1G>A mutation, while her mother and daughter were heterozygous for the Lys341Glu mutation. Bioinformatics analysis indicated that Lys341Glu mutation may affect the stability and function of the FⅦ protein.@*Conclusion@#The Lys341Glu and IVS6-1G>A mutations probably underlie the reduced activity of FⅦ in this pedigree.