SHANK2 and Cognitive impairment: SHANK mutations account for ∼1% of patients with autism and were detected in the whole spectrum of autism with a gradient of severity in cognitive impairment: mutations in SHANK1 were rare (0.04%) and present in males with normal IQ and autism; mutations in SHANK2 were present in 0.17% of patients with autism and mild intellectual disability; mutations in SHANK3 were present in 0.69% of patients with autism and up to 2.12% of the cases with moderate to profound intellectual disability [42].