We studied hyperuricemia associated with familial hypercholesterolemia (FH). Eighty-seven subjects with FH (47 males and 40 females) including five FH-homozygotes were investigated for serum uric acid. Serum uric acid levels were significantly higher than normal controls in male FH-heterozygotes(6.4±1.6mg/dl vs 5.1±1.0mg/dl, p<0.001)and also in female FH-heterozygotes(4.9±1.5mg /dl vs 4.1±1.0mg/dl, p<0.001). Three out of five FH-homozygotes showed hyperuricemia. The distribution curve of serum uric acid concentrations in FHsubjects was shifted to the right and the incidence of hyperuricemia (designated as. more than 7.0 mg/dl in male and 6.0 mg/dl in female ) was also high in both sexes. Serum uric acid levels did not correlate with the degree of hypercholesterolemia, but rather with the serum triglyceride values in female. Especially in female FH- subjects, serum levels of uric acid had a tendency to increase in WHO - phenotype II b and III. The underlying mechanism of hyperuricemia in FH is yet to be elucidated, but since HMG- CoA reductase activity is considerably elevated in FH, the de novo synthesis of uric acid might be linked together with the pathway for cholesterol de novo synthesis.
The incidence of gouty arthritis was unexpectedly low in FH inspite of hyperuricemia, which was considered to be in part due to the inhibition of gouty attack by elevated serum apolipoprotein B levels.
