Up to now, more than 83 WDSTS patients with variations in KMT2A gene were confirmed, most of them shared similar clinical features, such as hypertrichosis cubiti or back, developmental delay, cognitive disability, pre and postnatal growth retardation, and a distinctive facial appearance: palpebral fissures, down-slanted, wide nasal bridge, broad nasal tip, long eyelashes, and thick eyebrows. The gene discussed is KMT2A; the disease is Global developmental delay.