China ; Deafness ; genetics ; Humans

DNA, Mitochondrial ; genetics ; Deafness ; genetics ; Humans ; Mutation

Cochlea ; metabolism ; Deafness ; genetics ; Humans ; Mutation

Deafness ; diagnosis ; genetics ; Genetic Counseling ; Humans

Audiology ; Deafness ; genetics ; Humans ; Otolaryngology ; trends

Hearing loss is a common sensory deficit in humans. The hearing loss may be conductive, sensorineural, or mixed, syndromic or nonsyndromic, prelingual or postlingual. Due to the complexity of the hearing mechanism, it is not surprising that several hundred genes might be involved in causing hereditary hearing loss. There are at least 82 chromosomal loci that have been identified so far which are associated with the most common type of deafness--non-syndromic deafness. However, there are still many more which remained to be discovered. Here, we report the mapping of a locus for autosomal recessive, non-syndromic deafness in a family in Malaysia. The investigated family (AC) consists of three generations--parents who are deceased, nine affected and seven unaffected children and grandchildren. The deafness was deduced to be inherited in an autosomal recessive manner with 70% penetrance. Recombination frequencies were assumed to be equal for both males and females. Using two-point lod score analysis (MLINK), a maximum lod score of 2.48 at 0% recombinant (Z = 2.48, theta = 0%) was obtained for the interval D14S63-D14S74. The haplotype analysis defined a 14.38 centiMorgan critical region around marker D14S258 on chromosome 14q23.2-q24.3. There are 16 candidate genes identified with positive expression in human cochlear and each has great potential of being the deaf gene responsible in causing non-syndromic hereditary hearing loss in this particular family. Hopefully, by understanding the role of genetics in deafness, early interventional strategies can be undertaken to improve the life of the deaf community.
Deafness ; Family ; Relationship by association ; MALAYSIAN ; Linkage (Genetics)

DNA, Mitochondrial ; genetics ; Deafness ; chemically induced ; genetics ; Haplotypes ; Humans ; Mutation

OBJECTIVETo screen for mutations of deafness-related genes among ethic Chinese women of child-bearing age.

METHODSIn 324 women, 9 mutational sites in 4 deafness-related genes (SLC26A4, GJB3, GJB2 and mtDNA 12s rRNA) were screened using a gene chip.

RESULTSTwenty women (6.17%) have carried mutations. These included 11 (3.40%) carrying a GJB2 gene mutation, 7 (2.16%) carrying a SLC26A4 gene mutation, 1 (0.31%) simultaneously carrying GJB3 and GJB2 gene mutations, and 1 (0.31%) carrying a mtDNA 12s rRNA gene mutation.

CONCLUSIONWomen of child-bearing age have a high rate for carrying mutations of common deafness-related genes, among which 235delC in GJB2 was most common. Prenatal screening of couples with normal hearing is an effective way to prevent birth of affected children.

Deafness refers to different degrees of hearing loss (HL). The factors leading to HL are complex, among which heredity is a major one. Nonsyndromic hearing loss (NSHL) accounts for 80% of hereditary deafness. More than 140 genes have been regarded to be closely related to NSHL. The mutation of GJB2 (gap junction protein, beta 2) gene accounts for 80% of NSHL and more than 50% of children NSHL, playing the most important role in deafness genes. This paper reviewed the studies on the association between GJB2 gene mutation and HL to provide reference for genetic diagnosis and counseling.
Connexin 26 ; Connexins ; genetics ; Deafness ; genetics ; Humans ; Mutation

Humans ; Deafness/genetics* ; Hearing Loss, Sensorineural/genetics* ; Y Chromosome