Familial hypercatabolic hypoproteinemia caused by deficiency of the neonatal Fc receptor, FcRn, due to a mutant beta2-microglobulin gene.

ABSTRACT: Two siblings, products of a consanguineous marriage, were markedly deficient in both albumin and IgG because of rapid degradation of these proteins, suggesting a lack of the neonatal Fc receptor, FcRn. FcRn is a heterodimeric receptor composed of a nonclassical MHC class I alpha-chain and beta(2)-microglobulin (beta(2)m) that binds two ligands, IgG and albumin, and extends the catabolic half-lives of both. Eight relatives of the siblings were moderately IgG-deficient. From sera archived for 35 years, we sequenced the two siblings' genes for the heterodimeric FcRn. We found that, although the alpha-chain gene sequences of the siblings were normal, the beta(2)m genes contained a single nucleotide transversion that would mutate a conserved alanine to proline at the midpoint of the signal sequ

SUBMITTER: Wani MA 

PROVIDER: S-EPMC1458798 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature