The neuronal ceroid lipofuscinoses (CLN) are a group of conditions that are inherited in an autosomal recessive pattern. CLN1 is characterized by progressive microcephaly, contractures, developmental delay, psychiatric symptoms, and neurological degeneration including seizures and ataxia. Retinal and macular degeneration leads to blindness by the age of 2 years with diminished or abolished ERG results. Age of onset varies with infantile, late-infantile, juvenile and adult-onset forms of the disease with younger ages of onset typically associated with a more rapid progression of symptoms. The intracellular accumulation of lipopigments results in a characteristic microscopic pattern called granular osmiophilic deposits (GROD).