In cohorts with people with speech disorders, SETD1A haploinsufficiency therefore seems rather frequent (2 out of 123 people with CAS and 1 out of 23 people with speech delay) [13–15], compared to cohorts with people with schizophrenia (10 out of 7,776) or a neurodevelopmental disorder (4 out of 11,110) [47]. This evidence concerns the gene SETD1A and neurodevelopmental disorder.