Somatic and/or germline variants in numerous PI3K–AKT–mTOR pathway genes, including TSC2, TSC1, MTOR, PIK3CA, AKT3, RHEB, DEPDC5, NPRL3 and NPRL2, are known to be associated with malformations within the FCD–hemimegalencephaly spectrum55,135–139. The gene discussed is NPRL3; the disease is hemimegalencephaly.