Contribution of functional variation in the IL13 gene to allergy, hay fever and asthma in the NSHD longitudinal 1946 birth cohort.

BACKGROUND: Genetic variants of the two adjacent genes, IL13 and IL4 have frequently been reported as being associated with susceptibility to atopy and asthma, both in adults and children, and some studies also suggest association with lung function and chronic obstructive pulmonary disease. METHODS: In this study, we examined for the first time the effect of these variants in 2918 adults in a longitudinal birth cohort, the British National Survey of Health and Development, where there are extensive life style, developmental and environmental data. We examine two IL13 single nucleotide polymorphisms (SNPs) IL13 rs20541 (R110Q) and rs1800925 (-1024C>T) and one IL4 SNP, rs2070874 (-33C>T) with likely function. RESULTS: We show that IL13 rs20541 and rs1800925 are each significantly associated with self-reported asthma and allergy, and that this association is not confounded by any of the known developmental and environmental risk factors for asthma and atopy, including in particular place of birth. IL13 rs20541 does however act as a confounder for the IL13 rs1800925 associations, meaning that there is no statistical support for rs1800925 having an independent effect. There is nevertheless evidence for interaction between smoking and rs1800925, with allergy as outcome. None of the SNPs showed association with measures of lung function, nor any interaction with the effect of smoking on lung function. CONCLUSION: In a longitudinal population cohort we have established a role for polymorphism of IL13 in determining susceptibility to both atopy and asthma.

Genetic regulation of MUC1 alternative splicing in human tissues.

The membrane mucin MUC1 is aberrantly expressed in a variety of cancers, and in stomach, it is a ligand for Helicobacter pylori where it plays a role in gastric carcinogenesis. Splicing variation, leading to a 9-amino acid insertion in the signal peptide region, was proposed to be because of a single-nucleotide polymorphism (rs4072037) at the 5' end of exon 2, but is also reported to be cancer-associated. However, the effect of rs4072037 on this splicing event in healthy non-cancer tissues and on the additional spliceoforms ofMUC1, including those lacking the polymorphic tandem repeat (TR) domain, has never been investigated. Here we show that in both foetal and adult tissues of known genotype, there is clear evidence for the role of rs4072037 in controlling alternative splicing of the 5' exon 2 region of both full-length transcripts and those lacking the TR domain. Although there is some evidence for additional genetic and epigenetic influences, there is no indication of an effect of the TR domain on the proportions of the spliceoforms. In conclusion, over-representation of certain transcripts in tumour material cannot be evaluated without information on the SNP genotype as well.