title: Genetic and environmental influences on serum levels of human C4.
abstract: In a family study, levels of the C4 component of complement measured in 195 individuals show a continuous normal distribution. There is a slight but significant age effect, especially in females. Heritability is estimated at 62%. The effect of environment, however, remains substantial, and it is suggested that at some time during development the mechanism controlling the C4 levels establishes a general steady-state level whose effects remain after the divergence of sib environments with the approach of adulthood.
mesh_terms: D000328:Adult; D000367:Age Factors; D000483:Alleles; D000704:Analysis of Variance; D000818:Animals; D003181:Complement C4 / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D004777:Environment; D005260:Female; D005796:Genes; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic; D051381:Rats; D012044:Regression Analysis; D012737:Sex Factors
chemical_list: D003181:Complement C4