Identification of novel variants in the Myosin VIIA gene of patients with nonsyndromic hearing loss from Taiwan.
OBJECTIVE
To determine whether variants of exons 7, 11, 22 and 28 of the MYO7A gene are causes of nonsyndromic deafness in Taiwanese.


METHODS
We screened a total of 331 unrelated Taiwanese individuals (age range, 4-22 years), including 231 patients with severe to profound nonsyndromic hearing loss and 100 individuals with normal hearing. Genomic DNA was extracted from peripheral blood leukocytes and then subjected to PCR to amplify selected exons and flanking introns of the MYO7A gene; the amplified products were screened for base mutations by autosequence. Data from the two groups were then compared using the chi-square (chi(2)) test.


RESULTS
The analysis revealed six variants in 3 out of 4 screened exons and flanking intronic sequences of the MYO7A gene (exons 7, 11, and 22). Three missense variants were found only in patients with hearing loss and were heterozygous, including Arg206Cys, Arg206His and Thr381Met. A variant, c.IVS22+58G>A, was found in intron 22 of the MYO7A gene from both patients and control group. Allele frequencies of c.IVS22+58G>A were shown to be significant between the two groups using chi(2) test (P<0.05).


CONCLUSIONS
Our results indicate that Arg206 and Thr381 residues in the motor head region of MYO7A protein are critical sites and the mutations of these residues may lead to the development of nonsyndromic deafness.
Su
Mao-Chang
MC
Department of Otorhinolaryngology-Head & Neck Surgery, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC.
Yang
Jiann-Jou
JJ
Su
Ching-Chyuan
CC
Hsin
Chung-Han
CH
Li
Shuan-Yow
SY
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers; D005260:Female; D014644:Genetic Variation / Q000235:genetics*; D006311:Hearing Disorders / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D000081412:Myosin VIIa; D009218:Myosins / Q000235:genetics*; D010375:Pedigree; D017354:Point Mutation / Q000235:genetics; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
D017931:DNA Primers; C000631455:MYO7A protein, human; D000081412:Myosin VIIa; D009218:Myosins