Genetic and environmental determinants of 17 serum biochemical traits in Brazilian twins.

The genetic and environmental effects on the levels of 17 serum biochemical quantitative traits (calcium, phosphorus, glucose, urea nitrogen, uric acid, total protein, albumin, total bilirubin, alkaline phosphatase, lactate dehydrogenase (LDH), glutamic-oxaloacetic transaminase (SGOT), total lipid, cholesterol, triglyceride, alpha-lipoprotein, pre-beta-lipoprotein and beta-lipoprotein) were estimated in 105 pairs of healthy twins of both sexes (57 MZ and 48 DZ) by path analysis. The genotype effect h2 was significant for all traits (P less than 0.001) and its value extended from 0.52 (alpha-lipoprotein) to 0.81 (alkaline phosphatase), whereas environmental effect b2 was significant (P less than 0.05) in only 10 traits of the 17 analyzed, with the maximum value of 0.13 (cholesterol). Correlations between genotypes of paired traits were estimated and, of 136 values, 47 were significant at the 5% levels, thus indicating partial and common genetic mechanisms.