[A not-previously described hereditary neurological disease with a deficiency of sialic acid, galactose and N-acetylglucosamine of plasma glycoproteins].

We report on five girls (including monozygotic twins) with a newly recognized disease comprising severe neurologic disturbances, variable hepatomegaly, abnormal subcutaneous fat distribution and skeletal anomalies. The neurologic picture was characterized by moderate to severe psychomotor retardation, alternating internal strabismus , hypotonia, hyporeflexia and ataxia. Biochemical investigations showed a number of abnormalities such as tubular proteinuria, slightly increased serum transaminases, hypoalbuminemia, hypo-beta-lipoproteinemia and decreased serum thyroxine-binding globulin. Moreover there was retinitis pigmentosa, cerebellar hypotrophy and electrophysiologic evidence for a peripheral neuropathy. However, histologic examination of a nerve biopsy in one of the patients failed to show myelin abnormalities. On the other hand, abnormal lamellar inclusions were found in the lysosomes of some Schwann cells and of liver tissue as well. Additional investigations in four patients revealed a deficiency of sialic acid, galactose and N-acetylglucosamine of plasma glycoproteins. Enzymatic analysis of serum suggested a deficiency of an N-acetyl-glucosaminyltransferase. Remarkably, the (healthy) fathers but not the mothers presented the same carbohydrate deficiencies of plasma glycoproteins albeit to a much lesser degree. The mode of hereditary transmission of this disease remains unclear; the possibility of X-linked inheritance is under investigation.