Finally, 100% of cases with monogenic SHANK3 deletion had hypotonia and there was no significant difference between loss of SHANK3 alone and deletions encompassing more than SHANK3 gene in the prevalence of hypotonia, DD/ID, ASD, increased pain tolerance, gait abnormalities, impulsiveness, repetitive behaviors, regression and nonstop crying which were high in loss of SHANK3 alone group. The gene discussed is SHANK3; the disease is dentin dysplasia.