[Juvenile neuronal ceroid-lipofuscinosis with hypertrophic cardiomyopathy and left ventricular noncompaction: a case report]

Vision loss in juvenile neuronal ceroid lipofuscinosis (CLN3 disease)

Juvenile neuronal ceroid lipofuscinosis (JNCL; also known as CLN3 disease) is a devastating neurodegenerative lysosomal storage disorder and the most common form of Batten disease. Progressive visual and neurological symptoms lead to mortality in patients by the third decade. Although ceroid-lipofuscinosis, neuronal 3 (CLN3) has been identified as the sole disease gene, the biochemical and cellular bases of JNCL and the functions of CLN3 are yet to be fully understood. As severe ocular pathologies manifest early in disease progression, the retina is an ideal tissue to study in the efforts to unravel disease etiology and design therapeutics. There are significant discrepancies in the ocular phenotypes between human JNCL and existing murine models, impeding investigations on the sequence of events occurring during the progression of vision impairment. This review focuses on current understanding of vision loss in JNCL and discusses future research directions toward molecular dissection of the pathogenesis of the disease and associated vision problems in order to ultimately improve the quality of patient life and cure the disease.

A novel mutation af Cln3 associated with delayed-classic juvenile ceroid lipofuscinois and autophagic vacuolar myopathy

Juvenile neuronal-ceroid-lipofuscinosis (JNCL) is a lysosomal storage disease caused by mutations in CLN3. The most frequent mutation is a 1.02-kb deletion that, when homozygous, causes the classical clinical presentation. Patients harboring mutations different than the major deletion show a marked clinical heterogeneity, including protracted disease course with possible involvement of extraneuronal tissues. Cardiac involvement is relatively rare in JNCL and it is usually due to myocardial storage of ceroid-lipofuscinin. Only recently, histopathological findings of autophagic vacuolar myopathy (AVM) were detected in JNCL patients with severe cardiomyopathy. We describe a 35-year-old male showing a delayed-classic JNCL with visual loss in childhood and neurological manifestations only appearing in adult life. He had an unusual CLN3 genotype with an unreported deletion (p.Ala349_Leu350del) and the known p.His315Glnfs*67 mutation. Autophagic vacuolar myopathy was shown by muscle biopsy. At clinical follow-up, moderately increased CPK levels were detected whereas periodic cardiac assessments have been normal to date. Adult neurologists should be aware of protracted JNCL as cause of progressive neurological decline in adults. The occurrence of autophagic vacuolar myopathy necessitates periodic cardiac surveillance, which is not usually an issue in classic JNCL due to early neurological death.