Analysis of Family Resemblance for Immunoglobulin M, G and A Levels

Abstract

Analysis of family resemblance in several bodies of data shows that about half of the variation in serum concentrations of IgM, IgA, and IgG is genetic. A substantial part of the remainder is due to twin shared environment, the effect of which is not significant for other relatives.

Irf4 is a positional and functional candidate gene for the control of serum IgM levels in the mouse

“…36 Several familiarity and genetic studies have indicated that heritable components control the serum levels of IgE, IgA and IgG [37][38][39] and identified a number of loci influencing total serum levels of these antibodies in humans. [40][41][42] There is also convincing evidence for parent-offspring effects and genetic heritability in human serum IgM levels [37][38][39] as well as evidence for genetic control of natural IgM titers in mammals, 43 birds 44 and fish. 45 However, no linkage evidence for quantitative trait loci influencing serum IgM has been reported and the genetics of the homeostatic regulation of serum IgM remains largely unknown.…”

Familial resemblance for immunoglobulin levels

“…IgM is especially important in children since it is the first of the immunoglobulins to reach production comparable to adult levels after approximately the first year of life, whereas IgG responses mature at 5-6 years of age. However, in a study conducted in Brazil, which included MZ and DZ twins, environmental transmission was not significant at least for IgM (Barbosa et al 1981), and genetic factors were implicated.…”

“…For both IgA and IgG, twin and family studies have shown significant familial aggregation (Rowe et al 1968;Allansmith et al 1969;Kalff and Hijmans 1969;Billewicz et al 1974;Grundbacher 1974;Escobar et al 1978); summary analyses (Barbosa et al 1981) give heritability estimates of approximately 40% and 50% for IgA and IgG, respectively. Only one family study by Billewicz et al (1974) is available for IgD; their analysis led to the conclusion that genetic factors were minimal (h 2 = 0.08), although this appeared to be due to a rather low paternal half-sibling correlation of 0.02.…”

“…In one study, genetic factors accounted for approximately 50% of the total variance for IgM with little evidence for familial environmental effects (Barbosa et al 1981). The consistently higher mean IgM for females, and an apparent dose-response relationship between the number of X chromosomes and mean IgM, have lead to the suggestion of an X-linked regulatory factor (e.g., see Grundbacher 1972); however, there is contradictory evidence (Billewicz et al 1974;McGue et al 1990).…”

Sex-Linked Determinants for IgM?

“…Significant twin and familial aggrega tion for immunoglobulin M (IgM) levels has been reported, and Barbosa et al [1] estimated that genetic factors accounted for approximately 50% of the total vari ance for IgM with little evidence for famil ial environmental effects. The higher mean IgM for females has long been thought to be due to the effects of a, pre sumably dominant, X-linked gene [2].…”