title: A multigene deletion within the immunoglobulin heavy-chain region.
abstract: The immunoglobulin heavy-chain genes are located in a cluster on chromosome 14. The simultaneous absence of the human IgG1, IgG2, IgG4, and IgA1 subclasses was previously reported in a healthy Tunisian Berber and was later shown to be due to a multigene deletion. We now describe a serological and molecular study of a different deletion observed in a healthy Tunisian. Blot hybridization analysis of the proband's DNA using gamma, epsilon, alpha, and mu switch probes showed that the deletion involves a large region of the immunoglobulin heavy-chain gene cluster: C psi epsilon, C alpha 1, C psi gamma, C gamma 2, and C gamma 4. Incidentally, we showed that the restriction enzyme EcoRI alone can be used with the alpha probe to differentiate A2m types. The deletion described, present in a person homozygous for GM-Am haplotypes (Gm1,17;..;5,14,11,13,10 A2m2), is consistent with previous location, by association analysis, of C psi gamma between C alpha 1 and C gamma 2. There is evidence to suggest that deletions may be more common in the Mediterranean region than in North American Caucasians.
mesh_terms: D001483:Base Sequence; D002872:Chromosome Deletion; D004262:DNA Restriction Enzymes; D005796:Genes; D006801:Humans; D007126:Immunoglobulin Allotypes / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D012689:Sequence Homology, Nucleic Acid
chemical_list: D007126:Immunoglobulin Allotypes; D007143:Immunoglobulin Heavy Chains; D004262:DNA Restriction Enzymes