The first three Russian cases of classical, late-infantile, neuronal ceroid lipofuscinosis.

We describe the first three cases of classical, late-infantile, neuronal ceroid lipofuscinosis from Russia. All of the patients had seizures, myoclonia, cognitive deterioration, cerebellar and pyramidal signs and also optic atrophy. Parkinsonian features were observed in one case. Electroencephalogram, evoked potentials, fundoscopy and magnetic resonance imaging (MRI) findings were characteristic for classical, late-infantile, neuronal ceroid lipofuscinosis. There was also evidence of hypointensity of the thalami in T2-weighted MRI in one patient, which was not reported earlier. Nerve conduction velocity was slowed in one case. All patients were found to have significantly reduced tripeptidyl peptidase 1 activity. All patients were homozygous for g3670 C-->T (Arg208Stop) mutation. We presume that this mutation is common in Russia.