[Analysis of MYO15A variation in children with DFNB3].

Objective: To analyze the genetic and clinical characteristics of MYO15A variants associated non-syndromic autosomal recessive deafness3 (DFNB3). Methods: The hearing test and high-throughput sequencing data of 108 families with non-syndromic hearing loss, who visited the Center of Genetics and Prenatal Diagnosis in the First Affiliated Hospital of Zhengzhou University from November 2016 to February 2019, were retrospectively analyzed to investigate the characteristics of MYO15A variation. Results: Compound heterozygous MYO15A variations were detected in nine patients from eight families, accounting for 7.4% of all 108 families. The variants were c.5910+1G>A/c.9417_9418insTA, c.4234T>G/c.8324G>T, c.3926A>T/c.5002delC, c.9690+1G>A/c.10257_10259delCTT, c.8324G>T/c.10419_10423delCAGCT, c.4519C>T/c.6454G>C, c.6177+1G>T/c.10257_10259delCTT and c.5692C>T/c.7396-1G>A. All patients had severe to profound hearing loss. Among the 14 variations, 12 variations were located in the main structural domains, including 5 in motor domain, 3 in FERM domain, 3 in MyTH4 domain and 1 in IQ motif. The c.3926A>T, c.4234T>G, c.4519C>T, c.5002delC, c.6454G>C, c.8324G>T, c.9417_9418insTA and c.10419_10423delCAGCT had not been reported in the Human Gene Mutation Database up to February 2020. According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), 6 reported variants and the first reported c.4519C>T, c.5002delC, c.9417_9418insTA and c.10419_10423delCAGCT were identified as pathogenic variants, while c.8324G>T was likely pathogenic variant, and c.3926A>T, c.4234T>G and c.6454G>C were variants of uncertain significance. Conclusions: The variations of MYO15A in patients with DFNB3 are mainly complex heterozygous. The clinical phenotypes are mostly severe to profound hearing loss, and the mutation loci are mainly in the motor, FERM and MyTH4 domains.

[Analysis of genetic variation in patients with Waardenburg syndrome type â ¡ by next generation sequencing].

Objective: To detect gene mutation sassociated with deafness in four Waardenburg syndrome (WS) type Ⅱ patients, and to explore the possible mechanism of molecular genetics. Methods: All patients with WS were identified at the genetic and prenatal diagnosis center of the First Affiliated Hospital of Zhengzhou University from August 2015 to December 2018.Clinical materials and peripheral blood were collected from patients and family members. The genes associated with deafness of the patients were tested by next generation sequencing(NGS). And suspected mutations were verified by Sanger sequencing. Results: All patients carried heterozygous mutations in SOX10, they were c.355_356insTCAGGCAGCGC, c.1106_1107insTGGGGCCCCCCACACTA, c.511T>C (p.Y171H), c.91_100del. According to the guidelines for genetic variation of the Amercian College of Medical Genetics and Genomics (ACMG), three frameshift mutations were pathogenic mutations, one missense mutation was likely pathogenic mutation. Conclusion: Application of next generation sequencing technologies make gene diagnosis of Waardenburg syndrome efficiently and accurately.

[PAX3 gene mutation analysis for two Waardenburg syndrome type â families and their prenatal diagnosis].

Objective: To analyze the mutations of PAX3 gene in two Waardenburg syndrome type Ⅰ (WS1) pedigrees and make prenatal diagnosis for the high-risk 18-week-old fetus. Methods:PAX3 gene was first analyzed by Sanger sequencing and multiplex ligation-dependent probe amplification(MLPA) for detecting pathogenic mutation of the probands of the two pedigrees. The mutations were confirmed by MLPA and Sanger in parents and unrelated healthy individuals.Prenatal genetic diagnosis for the high-risk fetus was performed by amniotic fluid cell after genotyping. Results: A heterozygous PAX3 gene gross deletion (E7 deletion) was identified in all patients from WS1-01 family, and not found in 20 healthy individuals.Prenatal diagnosis in WS1-01 family indicated that the fetus was normal. Molecular studies identified a novel deletion mutation c. 1385_1386delCT within the PAX3 gene in all affected WS1-02 family members, but in none of the unaffected relatives and 200 healthy individuals. Conclusions:PAX3 gene mutation is etiological for two WS1 families. Sanger sequencing plus MLPA is effective and accurate for making gene diagnosis and prenatal diagnosis.