Leukocyte glycerolipid fatty acid compositions were determined in four patients of juvenile form of neuronal ceroid-lipofuscinosis (Battens disease), their parents and age-matched controls. A 54 to 93% reduction in docosahexaenoic acid (22:6, n-3) was noted in patient leukocytes. The parents also showed reduction in docosahexaenoic acid content, but to a lesser degree. The levels of linolenic family (n-6) polyunsaturated fatty acids were unchanged suggesting that the metabolic defect in this disease is specific to the linolenic family (n-3) of fatty acids.