In a cohort of 1170 unselected patients referred for developmental delay or ID, Cohen syndrome (COH1) [MIM# 216550] was found among several common genetic diagnoses for ID; and with a frequency of 0.7 %, COH1 is ranked right after Fragile-X syndrome (1.2 %) among patients with clear diagnosis of ID [2]. The gene discussed is VPS13B; the disease is Global developmental delay.