The role and spectrum of SLC26A4 mutations in Iranian patients with autosomal recessive hereditary deafness.

OBJECTIVE: To determine the prevalence and types of SLC26A4 mutations and the relevant phenotypes in a series of Iranian deaf patients.
DESIGN: A descriptive laboratory study. STUDY SAMPLE: One hundred and twenty-one families including 60 unrelated patients and 61 unrelated multiplex families with autosomal recessive deafness were included. In the 61 multiplex families, linkage was conducted for short tandem repeats (STRs) of the DFNB4. Selected individuals from the linked families and all of the 60 deaf individuals were subjected to sequencing of SLC26A4.
RESULTS: Seven out of the 61 (11.5%) families were linked to the locus which upon further inquiry led to identification of eight different mutations. Also, five out of the 60 (8.3%) patients were positive for the mutations. The SLC26A4 mutations clarified in 9.1% (12 families) of total investigated alleles included: c.2106delG, c.65-66insT, c.881-882delAC, c.863-864insT, c.1226G> A, c.1238A> G, c.1334T> G, c.1790T> C, c.1489G> A, c.919-2A> G (IVS7-2A> G), c.1412delT, and c.1197delT. Six out of 12 (50%) families with mutations were confirmed to be Pendred syndrome (PS).
CONCLUSIONS: The results probably suggest a high prevalence and specificity of SLC26A4 mutations among Iranian deaf patients. Molecular study of SLC26A4 may lead to elucidation of the population-specific mutation profile which is of importance in diagnostics of deafness.