To date, 17 cases with ID or global developmental delay from 16 families with KAT6A mutations have been reported.6–8 A recent large-scale study including more than 7,000 individuals with neurodevelopmental disorder identified 11 patients with potentially damaging KAT6A de novo mutations.3 This finding may reflect the actual frequency of the disease. This evidence concerns the gene KAT6A and Global developmental delay.