Wiedemann-Steiner syndrome (WSS) includes distinctive facial features, growth delay, and intellectual disability. Signs and symptoms vary, but facial features may include thick eyebrows, wide-spaced eyes, and narrow eye openings. People with WSS may also have excessive hair on the elbows, arms, and back; difficulty feeding; behavior problems; and seizures. Because WSS has been reported in a small number of individuals, there is not much information on how the symptoms and features change over time. WSS is caused by genetic changes in the KMT2A gene. Most individuals with WSS are the only ones in their family with this condition. In a few cases, WSS has been inherited in an autosomal dominant pattern. Diagnosis is based on the symptoms and clinical exam, and it is confirmed by the results of genetic testing.