A novel mutation in the CLN1 gene in a patient with juvenile neuronal ceroid lipofuscinosis.

We describe the clinical, neuropathological and molecular findings from a patient affected with neuronal ceroid lipofuscinosis with a juvenile onset (JNCL). She was a 9-year-old right-handed girl with a normal birth and early developmental milestones. At the age of 4 the early symptoms began. Skin biopsy showed granular osmiophilic deposits (GRODs). Because JNCL with GRODs is caused by mutations in the CNL1 gene, we performed a molecular investigation by direct sequencing of nine exons of the CNL1 gene. This analysis revealed a novel mutation in homozygous form in the exon 7 that caused an aminoacid substitution at codon 222 (Leu --> Pro). Direct sequencing of the exon 7 in both parents showed the same substitution in heterozygous form.