Mutational analysis of implicated genes in stuttering
To the best of our knowledge this is the first study to investigate three functionally related genes viz., GNPTAB , GNPTG andNAGPA implicated in stuttering, from India. We focused on the recurrence of the previously reported mutations in 64 probands. In a total of 12 variants identified only two co-segregated (c.3598G>A in GNPTAB - STU 29 and c.802A>C in GNPTG - STU 63) with the affected status resulting in a likely pathogenic allele frequency of 1.6%.
A meta-analysis of worldwide unrelated PWS, identified 81 rare nonsynonymous coding variants, in either of the three putative genes, accounting for a frequency of 16% (164/1013)20. In our study, we observed four rare nonsynonymous coding variants accounting for 6% (4/64). Among the twelve variants identified in this study, five of them (c.3598G>A, c.1932A>G inGNPTAB and c.131G>C, c.333 A>G, c. 1485C>T in NAGPA ) were previously reported in population with stuttering. One variant (c.702T>C inGNPTG ) was reported in mucolipidosis III. However, the remaining six variants (c.802A>C, c.813G>A, -4 C>T in GNPTG and c.139C>T, c.1394 C>T, c.1174+53C>A in NAGPA ) were just reported in the ExAC database. The three likely pathogenic nonsynonymous variants are discussed briefly: