Interleukin-4 gene promoter polymorphism [C590T] and asthma in Kuwaiti Arabs

Background: Recent studies have demonstrated an association of the T allele of a promoter polymorphism [C590T] of interleukin-4 (IL-4) gene with asthm a/atopy in the US and Japanese populations, but data from the UK and Austra lian families failed to find an association. We have investigated the assoc iation of this [C590T] promoter polymorphism in Kuwaiti Arabs with asthma. Methods: Th is study included (84 subjects (84 asthmatics and 100 non-asthm atics, 47 of whom were totally unrelated normal healthy controls with no hi story of asthma/atopy in three generations of near relatives). The [C590T] promoter polymorphism of the IL-4 gene was analyzed by a polymerase chain r eaction-restriction fragment length polymorphism method using the restricti on enzyme Avail. Results: The frequency of the T allele was found to be 0.7 9 in asthmatics, 0.75 in non-asthmatic first-degree relatives and 0.76 in u nrealted controls in Kuwaiti Arabs. No significant difference was detected in the distribution of the th ree genotypes (TT, CT and CC) between the ast hmatic, non-asthmatic relatives and the unrelated controls. The incidence o f co-existing phenotypes e.g. hay fever, eczema and a positive skin prick t est was significantly higher in asthmatics than in the non-asthmatics irres pective of the [C590T] genotype. However, within the asthmatic group, a hig her incidence of eczema was detected in asthmatics with a heterozygous CT g enotype compared to the asthmatics with a TT genotype. Conclusions: Our res ults do not show an association between [C590T] promoter polymorphism of th e IL-4 gene and asthma in Kuwaiti Arabs. Our results are in keeping with th e reports from the UK and Australian families (no association) but in contr ast to the findings from US and Japanese populations tan association report ed). copyright (C) 2000 S. Karger AG, Basel.