Abstract
A 47 year-old man who had cerebellar ataxia and low plasma lipids and lipoproteins was reported. Neurological examination revealed ataxic movements of the hands, inarticulate speaking and trembling gait. His tendon reflexes were hyperactive and pathological reflexes were present in the lower limbs. The sensory systems and nerve conduction velocity were normal. There were no abnormal findings on hematological examination. Total lipid (380mg/dl), total cholesterol (106mg/dl), free cholesterol (74mg/dl), triglyceride (58mg/dl), phospholipid (124mg/dl), and free fatty acid (303μEq/l) were generally decreased. On lipoprotein electrophoresis, prebetalipoprotein was very faint and migrated more slowly than normal. Betalipoprotein and alphalipoprotein were moderately reduced in concentration but migrated normally. The concentration of isolated VLDL was only one-tenth of normal subjects and it migrated as slow prebetalipoprotein. Although the lipid composition of VLDL was similar to those of normal VLDL, subunit analysis of apo VLDL on SDS polyacrylamide gel electrophoresis was somewhat different from normal apo VLDL. The concentration of isolated LDL was about one-half of normal subjects and HDL was almost normal. Lipid composition and subunit analysis of LDL and HDL were normal. The disturbances of lipid absorption and chylomicron formation were also shown on fat absorption test, but jejunal biopsy revealed intact endothelial cells with normal microvilli. In spite of mild elevation of serum bilirubin and marked retention of bromosulfouhthalein, serum GOT, GPT, Al-Phos. and γ-globulin remained in normal ranges. Liver biopsy specimen disclosed localized infiltration of round cells and swelling of the hepatocytes like the foamy cells suggesting steatosis of the liver cells. Only two of his relatives had low cholesterol levels although all were free from neurological disorders. According to these results, he was considered to have hypobetalipoproteinemia with abnormal prebetalipoprotein. Abnormal composition of apo VLDL seems to be responsible for reduced concentration and mobility of prebetalipoprotein. Reduced synthesis of beta and prebetalipoprotein may contribute to the developments of neurological symptoms and hepatic involvement.
