Contributor: Gordon K. Klintworth
The Finnish form of neuronal ceroid liopfuscinosis (infantile neuronal ceroid lipofuscinosis type II , Hagberg-Santavuori-Haltia disease, OMIM #256730) is a subtype of  neuronal ceroid lipofuscinosis caused by defects in the CLN1 gene which encodes the lysosomal enzyme palmitityl protein thioesterase.  The clinical onset is during the second year of life with non-specific signs.  Because of the considerable clinical variability an early diagnosis is difficult. The manifestations of this lethal neurodegenerative disorder include epilepsy, loss of vision, ataxia, loss of motor coordination and mental deterioration. Progressive intellectual regression, blindness, and cerebellar dysfunction result. All reported patients have been blind by the age of   2 years. Optic atrophy, retinal dystrophy with involvement of the macula has usually been present. A pigmentary retinopathy has not been documented. Early extinction of the ERG has been noted in most cases. Affected persons accumulate ceroid-lipofuscin within lysosomes of neurons and numerous other cell types.