Susceptibility to coeliac disease in Tunisian children and GM immunoglobulin allotypes

Coeliac disease is a malabsorption disorder of the small intestine resultin g from ingestion of gluten. The immunogenetic component is clearly demonstr ated by the association of the disease with human leukocyte antigens (HLA). Among other candidate genes are the GM allotypes, which are the markers of the constant parts of heavy chains of the subclasses IgC1, IgG2 and IgG3. GM immunoglobulin allotypes have been analysed in 131 unrelated Tunisian ch ildren with coeliac disease. All patients and their parents were tested for G1M(1, 2, 3, 17), G2M(23) and G3M(5, 6, 10, 11, 13, 14, 15, 16, 21, 24, 28 ) by the classical haemagglutination method. Genotypes and haplotypes were deduced from phenotypes in patients and their parents. Transmission disequi librium tests were performed in 79 informative families. The GM*3;..;5* hap lotype was transmitted more often (23) than not (8) by heterozygous parents (chi(2) = 7.26; P = 0.007). This difference remained significant after cor rection for multiple testing. This study provides evidence for association and linkage between GM and coeliac disease. It suggests that GM or genes cl ose to GM play a role in the development of the disease.