Abstract
More than 60% of prelingual deafness is genetic in origin, and of these up to 95% are monogenic autosomal recessive traits. Causal mutations have been identified in 1 of 38 different genes in a subset of patients with nonsyndromic autosomal recessive deafness. In this study, we screened 49 unrelated Turkish families with at least three affected children born to consanguineous parents. Probands from all families were negative for mutations in the
GJB2
gene, two large deletions in the
GJB6
gene, and the 1555A>G substitution in the mitochondrial DNA
MTRNR1
gene. Each family was subsequently screened via autozygosity mapping with genomewide single-nucleotide polymorphism arrays. If the phenotype cosegregated with a haplotype flanking one of the 38 genes, mutation analysis of the gene was performed. We identified 22 different autozygous mutations in 11 genes, other than
GJB2
, in 26 of 49 families, which overall explains deafness in 62% of families. Relative frequencies of genes following
GJB2
were
MYO15A
(9.9%),
TMIE
(6.6%),
TMC1
(6.6%),
OTOF
(5.0%),
CDH23
(3.3%),
MYO7A
(3.3%),
SLC26A4
(1.7%),
PCDH15
(1.7%),
LRTOMT
(1.7%),
SERPINB6
(1.7%), and
TMPRSS3
(1.7%). Nineteen of 22 mutations are reported for the first time in this study. Unknown rare genes for deafness appear to be present in the remaining 23 families.
