Chronic Catatonia in an Individual With a De Novo Missense <i>SHANK1</i> Variant

SHANK1 encodes a scaffolding protein of the SHANK family that includes SHANK1, SHANK2 and SHANK3. All of the SHANK proteins are enriched at the post-synaptic density of excitatory synapses. Here, we present an 11-year-old boy with a history of developmental delays and no family history of psychiatric disorders who developed catatonia. MRI of his brain and spine were negative as was a workup for autoimmune encephalitis. The proband's genetic testing revealed a de novo heterozygous SHANK1 missense variant. Although catatonia has been reported previously in individuals with SHANK3 loss-of-function mutations, this is the first time catatonia has been described in an individual with a SHANK1 variant.