Clinical and biochemical abnormalities in porcine GM2-gangliosidosis.

Abstract

Progressive clinical changes of GM2-gangliosidosis in a herd of inbred Yorkshire swine were reduced postnatal growth rate; incoordination, usually evident at 3 months of age; numerous, gray-white spots scattered through the retina; prominent, dark blue cytoplasmic granules in many neutrophils; and an increased frequency of azurophilic granules in lymphocytes. There was less N-acetyl-β-D-hexosaminidase in tissue homogenates from affected than from normal pigs, but there was more in serum from affected pigs than in serum from either carrier or normal pigs. The serum enzyme assay was a reliable test to distinguish carrier pigs from normal pigs; carrier pigs had moderate enzyme activity, and normal pigs had the lowest enzyme activity. The frequency of affected and carrier pigs in this herd suggested that porcine GM2-gangliosidosis is a familial disease transmitted as an autosomal recessive trait. Cerebral cortical ganglioside was about two times higher than normal in the stillborn and newborn affected pigs and three to four times higher than normal in the 140- to 167-day-old moribund affected pigs. The major cerebral cortical gangliosides in control pigs were GT1, GD1b, GD1a, and GM1, with only trace amounts of GM2-ganglioside. GM2-ganglioside was as much as 58% of the total gangliosides in the brains of moribund affected pigs. The clinical and biochemical features of porcine GM2-gangliosidosis closely resembled those of the juvenile (type AB) form of the disease in man.