Börjeson -Forssman -Lehmann syndrome: A case report / 中南大学学报(医学版)

Börjeson-Forssman-Lehmann syndrome (BFLS) is a rare X-linked intellectual disability. The main features of the patients include intellectual disability/global developmental delay, characteristic face, anomalies of fingers and toes, hypogonadism, linear skin hyperpigmentation, and tooth abnormalities in female patients, and obesity in male patients. A case of BFLS caused by a novel mutation of PHF6 gene who was treated in the Department of Pediatrics, Xiangya Hospital, Central South University was reported. The 11 months old girl presented the following symptons: Global developmental delay, characteristic face, sparse hair, ocular hypertelorism, flat nasal bridge, hairy anterior to the tragus, thin upper lip, dental anomalies, ankyloglossia, simian line, tapering fingers, camptodactylia, and linear skin hyperpigmentation. The gene results of the second-generation sequencing technology showed that there was a novel heterozygous mutation site c.346C>T (p.Arg116*) of the PHF6 (NM032458.3), variation rating as pathogenic variation. During the follow-up, the patient developed astigmatism, strabismus, awake bruxism, and stereotyped behavior, and the linear skin hyperpigmentation became gradually more evident. The disease is lack of effective therapy so far.

Analysis of IQSEC2 gene variant in a child with X-linked mental retardation / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and genetic variants of a child with X-linked mental retardation caused by IQSEC2 gene mutation, and provide reference for the diagnosis of the disease.@*METHODS@#The child was subjected to next generation sequencing (NGS), and the diagnosis was made by taking consideration of her clinical characteristics.@*RESULTS@#The child has presented with global developmental delay, particularly in fine motor skill and language development, in addition with intellectual disability. Genetic testing revealed that she has harbored a heterozygous c.1861dup variant of the IQSEC2 gene, which was not detected in either parent.@*CONCLUSION@#The de novo c.186ldup variant of the IQSEC2 gene probably underlay the X-linked mental retardation in this child. Above finding has, expanded the spectrum of IQSEC2 gene mutations and provide a basis for the diagnosis of similar cases.

Clinical characterization and genetic testing for a patient with creatine deficiency syndrome 1 / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child affected with cerebral creatine deficiency syndrome 1 (CCDS1).@*METHODS@#High-throughput sequencing was carried out to screen pathogenic variant associated with the clinical phenotype of the proband. The candidate variant was verified by Sanger sequencing.@*RESULTS@#High-throughput sequencing revealed that the proband has carried heterozygous c.327delG variant of the SLC6A8 gene, which was verified by Sanger sequencing.Neither parent was found to carry the same variant.@*CONCLUSION@#The de novo heterozygous c.327delG variant of the SLC6A8 gene probably underlay the CCDS1 in this child.

Clinical phenotype and genetic analysis of MECP2 duplication syndrome / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical symptom and parental origin of patients with MECP2 duplication syndrome in order to provide a basis for genetic counseling and prenatal diagnosis.@*METHODS@#Clinical symptoms of four patients who were diagnosed with MECP2 duplication syndrome by copy number variation sequencing (CNV-Seq) were reviewed. The maternal origin of the duplications were verified.@*RESULTS@#All patients were males, and CNV-Seq revealed that they have all harbored a duplication in the Xq28 region spanning 0.32 ~ 0.86 Mb, which were derived from asymptomatic mothers. The clinical symptoms of three patients with three copies included delayed speech, intellectual disability, and muscular hypotonia, while the patient with four copies had died at 6 months after birth, with clinical symptoms including recurrent infections, seizures, and spasticity.@*CONCLUSION@#The four cases of MECP2 duplication syndrome have shown complete penetrance and have all derived from asymptomatic mothers. As a stable and reliable method, CNV-Seq can accurately detect the MECP2 duplication syndrome.

Clinical and genetic analysis of a child with mental retardation and microcephaly with pontine and cerebellar hypoplasia / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and pathogenic variant in a child diagnosed with mental retardation and microcephaly with pontine and cerebellar hypoplasia (MICPCH).@*METHODS@#Clinical phenotype of the child was reviewed. Whole exome sequencing was carried out for the child. Candidate variant was verified by Sanger sequencing of the family member.@*RESULTS@#The proband manifested dyskinesia, development delay, cerebellar hypoplasia and bilateral hearing impairment. WES results revealed that the proband has carried a pathogenic c.1641_1644delACAA (p.Thr548Trpfs*69) variant of the CASK gene, which was verified by Sanger sequencing to be a de novo variant.@*CONCLUSION@#The c.1641_1644delACAA (p.Thr548Trpfs*69) variant of the CASK gene probably underlay the MICPCH in the proband. Above finding has provided a basis for genetic counseling. WES should be considered for the diagnosis of neurological dysplasia.

Clinical features and gene variant of a pedigree affected with X-linked recessive mental retardation Claes-Jensen type / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a pedigree affected with X-linked recessive mental retardation Claes-Jensen type.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the patient, his parents (phenotypically normal) and two elder brothers with similar clinical manifestations. Whole exome sequencing was carried out for the proband, and the result was verified by Sanger sequencing.@*RESULTS@#The proband was found to harbor a hemizygous c.1565C>T missense variant in exon 11 of the KDM5C gene. The transition has resulted in replacement of serine by phenylalanine at position 522 (p.Ser522Phe). Sanger sequencing showed that the patient's two elder brothers and mother carried the same variant, which was predicted to be probably damaging by SIFT, PolyPhen2 and Mutation_Taster. The three affected brothers presented with similar clinical phenotypes characterized by mental retardation, speech delay, behavioral problem, self-limited epilepsy responsible to medication, short stature and microcephaly. The mother only had mild cognitive impairment and learning disability. The same variant was not found in their father and was unreported previously.@*CONCLUSION@#The c.1565C>T (p.Ser522Phe) of the KDM5C gene probably underlay the X-linked recessive mental retardation Claes-Jensen type in this pedigree.

Molecular diagnosis and functional study of a pedigree affected with Lubs X-linked mental retardation syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a pedigree affected with X-linked mental retardation.@*METHODS@#The proband was subjected to chromosomal karyotyping, FMR1 mutation testing and copy number variation analysis with a single nucleotide polymorphism microarray (SNP array). His family members were subjected to multiplex ligation-dependent probe amplification (MLPA) assaying. Expression of genes within the repeated region were analyzed.@*RESULTS@#The proband had a normal chromosomal karyotype and normal number of CGG repeats within the FMR1 gene. SNP array identified a 370 kb duplication in Xq28 (ChrX: 153 027 633-153 398 515), which encompassed 14 genes including MECP2. The patient was diagnosed as Lubs X-linked mental retardation syndrome (MRXSL). MLPA confirmed the presence of copy number variation, its co-segregation with the disease, in addition with the carrier status of females. Genes from the duplicated region showed higher levels of expression (1.79 to 5.38 folds) within peripheral blood nucleated cells of the proband.@*CONCLUSION@#The patients were diagnosed with MRXSL. The expression of affected genes was up-regulated due to the duplication. Genetic counseling and prenatal diagnosis may be provided based on the results.

X-linked mental retardation combined with autism caused by a novel hemizygous mutation of GRIA3 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a family affected with mental retardation combined with autism.@*METHODS@#For the family featuring X-linked recessive inheritance of mental retardation combined with autism, clinical data and peripheral blood samples were collected. Potential mutations of genes associated with intellectual impairment were sequenced with an Ion PGM platform. Suspected mutations were verified with a PCR-Sanger sequencing method.@*RESULTS@#The patient with mental retardation had mild abnormal electroencephalograph(EEG), while brain MRI and CT scans showed no obvious abnormality. Two ABC (autism behavior checklist) testing scores were 73 and 66 when he was 7- and 13-year-old, respectively. A novel hemizygous mutation, c.64C>T (p.L22F), was detected in the GRIA3 gene in the patient, for which his mother was a heterozygous carrier. The mutation site was predicted to be possibly damaging and disease causing by PolyPhen_2 and MutationTaster.@*CONCLUSION@#The novel hemizygous c.64C>T (p.L22F) mutation of the GRIA3 gene probably underlies the phenotypes of mental retardation combined with autism in this family. Considering the variable clinical manifestation of mental retardation and genetic heterogeneity of autism, genetic testing is essential for making the correct diagnosis.

Snyder-Robinson syndrome

Snyder-Robinson syndrome, also known as spermine synthase deficiency, is an X-linked intellectual disability syndrome (OMIM #390583). First described by Drs. Snyder and Robinson in 1969, this syndrome is characterized by an asthenic body habitus, facial dysmorphism, broad-based gait, and osteoporosis with frequent fractures. We report here a pediatric autopsy of a 4 year old male with a history of intellectual disability, gait abnormalities, multiple fractures, and seizures previously diagnosed with Snyder-Robinson syndrome with an SMS gene mutation (c.831G>T:p.L277F). The cause of death was hypoxic-ischemic encephalopathy secondary to prolonged seizure activity. Although Snyder-Robinson syndrome is rare, the need to recognize clinical findings in order to trigger genetic testing has likely resulted in under diagnosis.

Analysis of a patient with X-linked mental retardation by next generation sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the clinical and genetic features of a Chinese boy featuring X-linked mental retardation.</p><p><b>METHODS</b>Clinical features of the patient were analyzed. The DNA of the patient and his parents was extracted and sequenced by next generation sequencing. The results were validated and analyzed with software.</p><p><b>RESULTS</b>The child displayed X-linked mental retardation. Sequencing showed the patient has carried a c.455T>C (p.L152P) mutation of the GRIA3 gene inherited from his mother.</p><p><b>CONCLUSION</b>The c.455T>C (p.L152P) mutation of the GRIA3 gene probably underlies the X-linked mental retardation in this child.</p>

MECP2 duplication syndrome: a clinical analysis of three cases and literature review / 中国当代儿科杂志

MECP2 duplication syndrome (MDS) is a rare pediatric disease and mainly manifests as delayed motor development, language loss or delay, recurrent infection, severe intellectual disability, epilepsy, autistic symptoms, and early infantile hypotonia. In this article, the three children with this disease were all boys. Cases 1 and 2 had delayed motor development, and language loss or delay as initial manifestations, and case 3 had recurrent infection as initial manifestation. Physical examination showed hypotonia and negative pathological signs in each case. Case 1 had tonic-clonic seizures and electroencephalography showed focal seizures, for which he was given oxcarbazepine, levetiracetam, and clonazepam as the antiepileptic treatment to control seizures. Case 3 experienced one absence seizure and three head-nodding seizures with normal electroencephalographic findings during these seizures, and therefore, he was not given antiepileptic treatment. In each case, recurrent infection was improved with the increase in age, but there were no significant improvements in language or intelligence. Array-based comparative genomic hybridization (aCGH) showed MECP2 duplication in X chromosome in each case, and so they were diagnosed with MDS. MDS should be considered for children with delayed development complicated by recurrent infection and epileptic seizures, and early aCGH helps with the diagnosis of this disease.

Advance in research on MECP2 corrected duplication syndrome / 中华医学遗传学杂志

Methyl-CpG-binding protein 2 gene (MECP2; OMIM 300005) is located at chromosome Xq28. Mutations of the gene including point mutation, duplication and deletion can lead to severe neurodevelopmental disorders. The disease caused by duplication of the entire MECP2 gene, named as MECP2 duplication syndrome, is mostly seen in males. The clinical manifestation of this syndrome include mental retardation, hypotonia, poor speech development, recurrent infection, progressive spasticity, epilepsy, autism or autistic features with or without midface hypoplasia. Most patients have inherited the duplication from their unaffected mothers, with only a few cases having de novo mutation. Females with duplicated MECP2 gene are typically asymptomatic because of a skewed X chromosome inactivation (XCI) pattern. Proposed mechanisms of this genomic rearrangement include fork stalling and template switching (FoSTeS) and microhomology mediated break-induced replication (MMBIR). Since no effective treatment is available for this disease, proper genetic counseling and prenatal diagnosis for the high risk families are crucial.

Diagnosis of MECP2 duplication syndrome with molecular genetic techniques / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate whether the four boys with delayed motor development and intellectual disability suffer from MECP 2 duplication syndrome.</p><p><b>METHOD</b>Blood specimens and clinical data of four patients and mothers of patient 2 and patient 4 were collected. Genomic DNA was extracted from peripheral blood using DNA extraction kit. At first multiplex ligation-dependent probe amplification (MLPA) was employed in 4 patients, two distinct kits SALSA P036 and P070 for sub-telomere screening, and SALSA P245 for the 22 common microdeletion and microduplication syndromes. Then array-CGH analysis was carried out. Two mothers of patients were tested by array- comparative genomic hybridization (CGH) and X chromosome inactivation analysis.</p><p><b>RESULT</b>All the 4 patients presented with severe hypotonia, delayed motor development, intellectual disability and absent or limited language. Three patients manifested recurrent pneumonia in infancy except patient 2. Four patients had duplication on chromosome Xq28 with MLPA kit SALSA P245. Array-CGH identified the size of each duplication on Xq28. The precise size of each duplication was different in the four patients: patient 1, 14.931 Mb, patient 2, 0.393 Mb, patient 3, 0.482 Mb and patient 4, 0.299 Mb. To compare Xq28 duplications with UCSC database (http://genome.ucsc.edu/) revealed that each duplication harbors the MECP 2 and HCFC 1 gene. Mothers of patient 2 and patient 4 also carried microduplication on Xq28. X chromosome inactivation analysis demonstrated completely skewed inactivation (0: 100) and it is the inactive allele that passed on to the patients.</p><p><b>CONCLUSION</b>For patients that present with delayed motor development, intellectual disability, hypotonia, absent or limited language and recurrent infection, combination of MLPA and array- CGH is effective and specific diagnostic methods of MECP 2 duplication syndrome.</p>

Mutation analysis for a Chinese family featuring X-linked alpha thalassemia/mental retardation syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify potential mutation in a Chinese family featuring X-linked alpha thalassemia/mental retardation syndrome (ATR-X).</p><p><b>METHODS</b>Based on clinical symptoms and inheritance pattern, linkage analysis of X chromosome short tandem repeats (X-STR) loci was carried out to locate the candidate gene. Subsequently, sequences of exons and exon-intron boundaries of the candidate gene were amplified with polymerase chain reaction (PCR). Potential mutations were detected by direct DNA sequencing. All patients were also analyzed for the trait of thalassemia.</p><p><b>RESULTS</b>Linkage analysis indicated the candidate gene to be ATRX. Subsequently, a homozygous missense mutation c.736C>T (p.R246C) was found in exon 9 of ATRX in all of the 3 patients. And a heterozygous mutation c.736C>T (p.R246C) was also identified in the patient's mother and grandmother. Similar mutations were not detected in other members of the family. Alpha thalassemia was detected in the proband and another patient, whose genotypes were determined as -α(3.7)/αα and --(sea)/αα, respectively.</p><p><b>CONCLUSION</b>Missense mutation of c.736C>T in ATRX gene is a mutation hotspot, and p.R246C may disturb the function of ATRX-DNMT3-DNMT3L domain (ADD), which may be responsible for the disease in this family.</p>

MED12 mutations in human diseases

The Mediator Complex plays key roles in activating gene transcription in eukaryotes. Mediator of RNA polymerase II transcription subunit 12 homolog (MED12) is a subunit of the Mediator Complex and regulates the activity of the complex. MED12 is involved in a variety of cellular activities, and mutations in MED12 gene impair MED12 activities and are associated with several diseases, including Opitz-Kaveggia syndrome, Lujan syndrome, uterine leiomyomas and prostate cancer. This review will discuss the biological function of MED12 and the relationship between MED12 mutations and diseases.

Mutation analysis of a family with 2-Methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency / 中华儿科杂志

<p><b>OBJECTIVE</b>The aim of this study was to explore the genetic features of a family with 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency (MHBDD) which may provide the basis for the diagnosis and genetic counseling.</p><p><b>METHOD</b>Clinical data of the proband was collected, total RNA and genomic DNA were extracted from the peripheral blood. The whole coding region of the ACAT1 gene was amplified by RT-PCR. 5' noncoding region of the ACAT1 gene and all 6 exons and flanking intron regions of the HADH2 gene were amplified by PCR. All amplification products were directly sequenced and compared with the reference sequence.</p><p><b>RESULT</b>(1) The patient was a one-year-old boy who presented with psychomotor retardation and astasia when he was admitted to the hospital. Biochemical test revealed slight hyperlactatemia (3.19 mmol/L) and magnetic resonance imaging showed delayed myelination. 2-Methylacetoacetyl-CoA thiolase deficiency was suggested by gas chromatography-mass spectrometry. (2) There was no mutation in the ACAT1 gene and a hemizygous missense mutation c.388C > T was found in the 4 exon of the HADH2 gene which resulted in p. R130C. Proband's mother was the heterozygote and the father was normal.</p><p><b>CONCLUSION</b>This is the first report on MHBDD patient and HADH2 mutation in China. p.R130C is responsible for the pathogenesis of the disease in the infant.</p>

Mutational screening of ARX gene in Iranian families with X-linked intellectual disability

Mutations in the human aristaless-related homeobox [ARX] gene are amongst the major causes of developmental and neurological disorders. They are responsible for a wide spectrum of phenotypes, including nonsyndromic X-linked intellectual disability [NS-XLID], and syndromic [XLIDS] forms such as X-linked lissencephaly with abnormal genitalia [XLAG], Partington syndrome [PRTS], and X-linked infantile spasm syndrome [ISSX]. The recurrent 24 bp duplication mutation, c.428_451dup[24 bp], is the most frequent ARX mutation, which accounts for 40% of all cases reported to date. We have screened the entire coding sequences of the ARX gene in 65 Iranian families with intellectual disabilities in order to obtain the relative prevalence of ARX mutations. At first these families were screened for the most recurrent mutation, the c.428_451dup[24 bp]. For samples with negative results, single strand conformation polymorphism [SSCP] analysis was performed. We identified one family with the c.428_451dup[24 bp] duplication. Three shifts [one shift in exon 5 and two shifts in exon 4] were also identified among the total families. According to the results of the sequencing analysis, two shifts were not associated with any mutation and the other one was a c.1347C>T [p.G449G] substitution in exon 4. Hence, we suggest that molecular analysis of ARX mutations as a second cause of XLID should be considered as routine diagnostic procedure in any male who presents with either NS-XLID or XLIDS

ATR-X syndrome in two siblings with a novel mutation (c.6718C>T mutation in exon 31).

ATR-X syndrome is an X-linked mental retardation syndrome characterized by mental retardation, alpha thalassaemia and distinct facial features which include microcephaly, frontal hair upsweep, epicanthic folds, small triangular nose, midface hypoplasia and carp-shaped mouth. Here we report two brothers with clinical features of ATR-X syndrome, in whom a novel missense (C>T) mutation was identified in exon 31 of the ATRX gene.

Síndrome de Lujan-Fryns: recorrência familiar na mesma geração / Lujan-Fryns syndrome: familial recurrence in the same generation

Objetivos: relatar casos da Síndrome de Lujan-Fryns em dois irmãos.Descrição dos casos: Paciente 1 ? sexo masculino, 18 anos, apresentando alta estatura, hiperextensibilidade articular, região frontal proeminente, face longa e estreita, hipoplasia do maxilar, mandíbula pequena, nariz largo com ponte nasal alta e estreita, filtro curto e profundo, lábio superior fino e palato arqueado, voz hipernasal e hipotonia generalizada. Instabilidade emocional, distúrbio de aprendizagem, timidez e fobia social. Prolapso de válvula mitral com refluxo discreto e ectasia da raiz da aorta Miopia, sem retinopatia. Resultados normais para cariótipo em sangue periférico com banda G, análise molecular para X frágil e investigação para homocistinúria. Paciente 2 ? sexo feminino,22 anos, apresenta quadro clínico semelhante ao paciente 1 (seu irmão), porém de intensidade mais leve. Exames complementares sem alterações significativas.Conclusões: os pacientes apresentam aspecto marfanóide e retardo mental compatível com herança ligada ao X. Apesar de ainda não ter sido realizada a pesquisa da mutação no gene MED 12, o diagnóstico clínico de Síndrome de Lujan-Fryns está respaldado pela literatura. Não existe tratamento específico e os pacientes requerem educação especial e acompanhamento psicológico.

Aims: To report cases of Lujan-Fryns syndrome in two siblings.Description of cases: Patient 1 ? male, 16 years, presented high stature, hiperextensibility of joints, prominent forehead, long face and narrow, maxillary hypoplasia, small jaw, large nose with high and narrow nasal bridge and short and deep filter, thin upper lip and arched palate, hypernasal voice and generalized hypotonia. Lability, learning disabilities, timidity and social phobia. Mitral valve prolapse with slight reflux and dilatation of the aortic root. Myopia without retinopathy. Karyotype in peripheral blood with G-band, molecular analysis for fragile X and biochemical investigation for homocystinuria had normal results. Patient 2 ? female, 19 years, presented clinical symptoms similar to the patient 1 (her brother), although milder. Complementary tests showed no significant changes.Conclusions: These patients present marfanoid aspect and mental retardation consistent with X-linked inheritance. Although no research has been carried out on mutation in the gene MED 12, the clinical diagnosis of Lujan-Fryns syndrome is supported by the literature. There is no specific treatment, and the patients require special education and psychological counseling.