(iii) STU 34 family with c.131G>C variant inNAGPA gene
We observed this variant in both affected and unaffected family members.
This may be explained by incomplete penetrance that may fail to show any
symptoms in unaffected or could be due to phenocopies in affected
members who may not be real carriers of variant but tend to display
stuttering under environmental effects19. Also
variants observed in normal individuals may cause stuttering but left
un-informative owing to early recovery28 but in our
family no such recovery was reported.
Since its frequency was also low in ExAC database the role of this
variant remains inconclusive. In addition to this the conservation score
is also found to be low across the species. Only one
study21 has reported this variant among stuttering
population of European descent.