SYNJ1 and Parkinson disease: Mutation of SYNJ1 is associated with two distinct phenotypes; a known homozygous missense mutation (p.Arg258Gln) associated with early-onset Parkinson disease (MIM 615530), whereas mutation with complete loss of SYNJ1 function result in a lethal neurodegenerative disease with intractable seizure and tauopathies (MIM 617389).<h4>Methods</h4>We report two related children from consanguineous family presented with intractable seizure, profound developmental delay, failure to thrive, acquired microcephaly, and hypotonia.