Analysis of p.Gly12Valfs*2, p.Trp24* and p.Trp77Arg mutations in GJB2 and p.Arg81Gln variant in LRTOMT among non syndromic hearing loss Egyptian patients: implications for genetic diagnosis.

Hearing loss (HL) is a global sensory disorder that affects children and deprives them from their rights to enjoy standard social and educational levels. Although hundreds of genetic mutations across several genes have been linked to HL, very limited studies are available on Egyptian population which has high rate of consanguinity and HL. The frequency of the p.Gly12Valfs2, p.Trp24 and p.Trp77Arg mutations in GJB2 along with the p.Arg81Gln variant in LRTOMT gene was investigated in Egyptian patients. 103 non-syndromic HL (NSHL) Egyptian patients and 100 control subjects were recruited in this study. PCR-RFLP and Direct sequencing were performed to screen and confirm presence/absence of those mutations in Egyptian population. The p.Gly12Valfs2 mutation was found in eight patients (7.8%) (six homozygous and two heterozygous) with an allele frequency of 6.8%. The p.Trp24 and p.Trp77Arg were absent in both HL patients and controls. Another one patient had the heterozygous variant for p.Arg81Gln in LRTOMT gene. This study reports, for the first time, the presence of a heterozygous change for the p.Arg81Gln in LRTOMT gene in one Egyptian patient. The p.Gly12Valfs2 mutation, but not the p.Trp24 nor the p.Trp77Arg, in GJB2 is the most frequent variant among Egyptian patients and would therefore be recommended for genetic counseling and diagnosis.