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. This evidence concerns the gene SYNJ1 and Failure to thrive.