SNAP29 and autosomal dominant nocturnal frontal lobe epilepsy: Finally, though one patient with ADNFLE (autosomal dominant nocturnal frontal lobe epilepsy) was shown to carry a single heterozygous truncating mutation in SNAP298, abnormalities have not been reported in heterozygous parents of children with CEDNIK syndrome, consistent with the hypothesis that mutations in SNAP29 result in variable expressivity and incomplete penetrance.