Homozygous or compound heterozygous pathogenic variants in the TMTC3 gene have been reported in thirteen patients to date exhibiting severe psychomotor retardation, intellectual disability, poor or absent speech, seizures, and muscular hypotonia. Many of these patients show a phenotype which is accompanied by neuronal migration defects expressed as either cobblestone lissencephaly or periventricular hypertopias.
TMTC3