scholarly journals P. [V27i; E114g] Compound Heterozygous State in Gjb2 Gene Could Be an Indicator of the Severity of Congenital Hearing Loss

2015 ◽  
Vol 05 (05) ◽  
Author(s):  
Tufan T Erkoc MA ◽  
Yilmaz MB Comertpay G
Keyword(s):  
Hearing Loss ◽  
Gjb2 Gene ◽  
Compound Heterozygous ◽  
Heterozygous State ◽  
Congenital Hearing Loss ◽  
Compound Heterozygous State

scholarly journals Progressive Early-Onset Leukodystrophy Related to Biallelic Variants in the KARS Gene: The First Case Described in Latin America

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1437
Author(s):  
Adriana Vargas ◽  
Jorge Rojas ◽  
Ivan Aivasovsky ◽  
Sergio Vergara ◽  
Marianna Castellanos ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gene Mutations ◽  
Mitochondrial Respiratory Chain ◽  
Trna Synthetase ◽  
Transfer Rna ◽  
Compound Heterozygous ◽  
Heterozygous State ◽  
Aminoacyl Trna Synthetase ◽  
First Case ◽  
Compound Heterozygous State

The KARS gene encodes the aminoacyl-tRNA synthetase (aaRS), which activates and joins lysine with its corresponding transfer RNA (tRNA) through the ATP-dependent aminoacylation of the amino acid. KARS gene mutations have been linked to diverse neurologic phenotypes, such as neurosensorial hearing loss, leukodystrophy, microcephaly, developmental delay or regression, peripheral neuropathy, cardiomyopathy, the impairment of the mitochondrial respiratory chain, and hyperlactatemia, among others. This article presents the case of a Colombian pediatric patient with two pathological missense variants in a compound heterozygous state in the KARS gene and, in addition to the case report, the paper reviews the literature for other cases of KARS1-associated leukodystrophy.

Progressive Early Onset Leukodystrophy Related to Biallelic Variants in the KARS Gene: The First Case Described in Latin America

2020 ◽  
Author(s):  
Adriana Vargas-Niño ◽  
Jorge Rojas-Martinez ◽  
Ivan Aivasovsky-Trotta ◽  
Sergio Vergara-Cardenas ◽  
Marianna Castellanos-Fernandez ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gene Mutations ◽  
Mitochondrial Respiratory Chain ◽  
Trna Synthetase ◽  
Transfer Rna ◽  
Compound Heterozygous ◽  
Heterozygous State ◽  
Aminoacyl Trna Synthetase ◽  
First Case ◽  
Compound Heterozygous State

The KARS gene encodes the aminoacyl-tRNA synthetase (aaRS) which activates and joins the lysin with its corresponding transfer RNA (tRNA), through the ATP-dependent aminoacylation of the amino acid. The KARS gene mutations have been linked to diverse neurologic phenotypes such as: neurosensorial hearing loss, leukodistrophy, microcephaly, developmental delay or regression, peripheral neuropathy, cardiomyopathy, impairment of the mitochondrial respiratory chain, hyperlactatemia, among others. This article presents the case of a Colombian pediatric patient with two pathological missense variants in a compound heterozygous state in the KARS gene.

scholarly journals Audiological features in Serbian patients with hearing impairment identified with c.35delG in the GJB2 gene

2021 ◽  
pp. 98-98
Author(s):  
Bojana Dobric ◽  
Danijela Radivojevic ◽  
Jovana Jecmenica ◽  
Vassos Neocleous ◽  
Pavlos Fanis ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hearing Impairment ◽  
Autosomal Recessive ◽  
Gjb2 Gene ◽  
Compound Heterozygous ◽  
Heterozygous State ◽  
Phenotype Correlation ◽  
Pathogenic Variants ◽  
Environmental Causes ◽  
35Delg Mutation

Introduction/Objective. Hearing impairment (HI) is the most common sensorineural disorder with an incidence of 1/700-1000 newborns. Variants in the GJB2 gene are the major cause of autosomal recessive nonsyndromic sensorineural hearing loss (ARNSHL). The degree of HI in patients with detected mutations in GJB2 gene ranges from mild to profound. The aim of this study was to determine possible genotype-phenotype association between audiometric characteristics and detected genotypes in ARNSHL patients from Serbia. Methods. Ninety-two patients with ARNSHL underwent genetic analysis with PCR-ARMS and sequencing of the GJB2 gene. Audiological analyses were obtained in all patients using a combination of several methods to estimate the degree of hearing loss. Results. Audiological analysis performed in the 92 probands showed moderate to profound range of hearing loss. All identified pathogenic variants accounted for 42.39% of the mutant alleles (78/184 alleles), with the c.35delG mutation being the most frequent (30.43%). Genotype-phenotype correlation in an isolated group of 37 patients bearing c.35delG in the homozygous, compound heterozygous or heterozygous state. In this group the majority of patients (30/37, 81.08%) exhibited severe to profound hearing deficit. Conclusion. Association between genotype and the degree of hearing impairment in patients analyzed in this study demonstrated that patients with bi-allelic truncating mutations i.e. c.35delG, associate with the more severe hearing loss when compared with those identified with only one affected allele. The various degrees of hearing impairment observed in heterozygous patients could be explained by the presence of an undetected second mutation or other modifier genes or environmental causes.

scholarly journals A novel LOXHD1 variant in a Chinese couple with hearing loss

2019 ◽  
Vol 47 (12) ◽  
pp. 6082-6090 ◽  
Author(s):  
Chuan Zhang ◽  
Shengju Hao ◽  
Yali Liu ◽  
Bingbo Zhou ◽  
Furong Liu ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Molecular Diagnosis ◽  
Protein Function ◽  
Mexican American ◽  
Compound Heterozygous ◽  
Congenital Hearing Loss ◽  
Targeted Next Generation Sequencing ◽  
Novel Variants ◽  
Novel Variant ◽  
Compound Heterozygous Variants

Objective To perform molecular diagnosis and genetic counseling in a young Chinese couple with congenital hearing loss. Methods Variant screening analysis was performed by PCR and direct Sanger sequencing or targeted next-generation sequencing of all known hearing loss genes. Novel variants were evaluated by PolyPhen2 and PROVEAN software tools to evaluate possible effects on protein function. Results We identified causative variants in the young couple: c.235delC (rs80338943)/c.299-300delAT (rs111033204) compound heterozygous variants of GJB2 in the husband and c.1828G>A (p.Glu610Lys, rs535637788)/c.2825-2827delAGA compound heterozygous variants of LOXHD1 in the wife. The LOXHD1 c.1828G>A variant has only previously been reported in a Mexican-American individual in the 1000 Genomes Project database. Using PolyPhen2 and PROVEAN, we speculated that the LOXHD1 variant c.1828G>A is potentially pathogenic. Conclusion We carried out molecular diagnosis in a young couple with congenital hearing loss, and identified different disease-causing genes in the two individuals. The LOXHD1 variant c.1828G>A present in the wife had not previously been reported in individuals with congenital hearing loss. We determined this to be a potential pathogenic variant, and a novel variant associated with hearing loss in a Chinese individual.

scholarly journals Spectrum and Frequency of the GJB2 Gene Mutations Among Latvian Patients with Prelingual Nonsyndromic Hearing Loss

2009 ◽  
Vol 63 (4-5) ◽  
pp. 198-203
Author(s):  
Olga Šterna ◽  
Natālija Proņina ◽  
Ieva Grīnfelde ◽  
Sandra Kušķe ◽  
Astrīda Krūmiņa ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gene Mutations ◽  
Gjb2 Gene ◽  
Connexin 26 ◽  
Compound Heterozygous ◽  
Nonsyndromic Hearing Loss ◽  
Profound Hearing Loss ◽  
Common Cause ◽  
Gjb2 Mutation ◽  
35Delg Mutation

Spectrum and Frequency of the GJB2 Gene Mutations Among Latvian Patients with Prelingual Nonsyndromic Hearing Loss Mutations in the GJB2 gene (connexin 26) are the most common cause of congenital nonsyndromic severe-to-profound hearing loss. Sixty-five hearing impaired probands from Latvia were tested for mutations in the GJB2 gene to determine the percentage of hearing loss attributed to connexin 26 and the types of mutations in this population. A total of 62% of patients tested had GJB2 mutations. Four different mutations in the GJB2 gene were identified in Latvian patients with nonsyndromic sensorineural hearing loss: 35delG, 311-324del14, 235delC and M34T. The most prevalent mutation is 35delG (47% of all probands were homozygous and 8% compound heterozygous). Our findings support the conclusion that the 35delG mutation is the most prevalent GJB2 mutation and that it is the common cause of hereditary nonsyndromic hearing loss in populations of European descent.

Phenotypic expression of a novel C282Y/R226G compound heterozygous state in HFE hemochromatosis: Molecular dynamics and biochemical studies

2014 ◽  
Vol 52 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Christine Cézard ◽  
Amrathlal Rabbind Singh ◽  
Gérald Le Gac ◽  
Isabelle Gourlaouen ◽  
Claude Ferec ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Phenotypic Expression ◽  
Compound Heterozygous ◽  
Heterozygous State ◽  
Biochemical Studies ◽  
Compound Heterozygous State
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