Objective: To ascertain the frequency and characteristics of myosin 7a gene mutations in Chinese with prelingual nonsyndromic hearing impairment.
Methods: Most of cases were collected within Hunan province, including 31 sporadic congenital deaf patients and 65 patients from 34 hereditary prelingual deafness families, and 100 health individuals were used as control. Genomic DNA was extracted from the patients and subjected to the PCR to amplify selected exons of myosin 7a gene, and then the amplified products were screened for base variations by single strand conformational polymorphismanalysis (SSCP). The bands with abnormal conformation were sequenced to confirm the mutation.
Results: G to A substitution was detected at nucleotide 617 in exon 7 as hetrozygous state in two patients and was not found in unaffected members in their family. This mutation caused Arg206Gln within a highly conserved heptapeptide sequence of myosin 7a protein, and was close relevant to the prelingual nonsyndromic deafness.
Conclusions: The Arg206Gln mutation in exon 7 of myosin 7a is possibly a novel mutation to cause prelingual nonsyndromic hearing impairment. Our results provide the evidence that exon 7 of Myosin 7a is a mutational hotspot region in genetic deafness.