Hypercholestanolemia in Diagnosing Cerebrotendinous Xanthomatosis vs. Familial Hypercholesterolemia, Primary Biliary Cirrhosis, and Hypothyroidism

The serum cholestanol level and the cholestanol/cholesterol ratio were found to be elevated in patients with heterozygous familial hypercholesterolemia, primary biliary cirrhosis, hypothyroidism and in cerebrotendinous xanthomatosis. These biochemical parameters were markedly increased in cerebrotendinous xanthomatosis. These two parameters, the serum cholestanol level and the cholestanol/cholesterol ratio, showed no significant difference of discrimination on diagnosing cerebrotendinous xanthomatosis. In cerebrotendinous xanthomatosis there was a significant positive correlation between the thickness of xanthomas of the Achilles tendon and the serum cholestanol level or the cholestanol/cholesterol ratio. Serum cholestanol elevation was not specific to cerebrotendinous xanthomatosis, however, the serum cholestanol level and the cholestanol/cholesterol ratio together appeared to reflect the severity of this disorder. All patients with CTX showed normocholesterolemia. The finding of both hypercholestanolemia and normocholesterolemia appears to be highly specific for diagnosing CTX.