New enzymatic findings in infantile neuroaxonal dystrophy.

Two siblings with infantile neuroaxonal dystrophy (INAD) exhibited highly increased activity of nonspecific esterase (resistant to physostigmine and sensitive to organophosphates) topically correlating with the morphological manifestations of the disease (spheroids), confined in those two particular cases to the central nervous system (CNS). This is demonstrated for the first time. NADH tetrazolium reductase was another enzyme noted with increased activity and similar topography. The lesions were devoid of any marked activity of typical mitochondrial (succinate and alpha-glycerolphosphate) dehydrogenases and lysosomal (acid phosphatase and beta-glucuronidase) enzymes. The diagnostic significance of monitoring non-specific esterase and NADH tetrazolium reductase activities in the diagnosis of INAD is discussed in particular.