Identification of a novel single-nucleotide polymorphism (Val1554lle) and definition of eight common alleles for human IL4RA exon 11

The interleukin (IL)-4 receptor a chain gene (IL4RA) is a polymorphic gene which is reportedly involved in the development of atopy. Of the 14 single- nucleotide polymorphisms (SNP) reported to date in the coding region of IL4 RA, 11 are positioned to exon 11. This big exon encodes more than two third s of the mature protein, including most of the cytoplasmic region. Here we report the identification of a new IL4RA SNP at the first nucleotide of cod on 554 (GTA-->ATA) in exon 11, leading to an amino acid substitution from V al to Ile (V554I). Furthermore, we present complete nucleotide sequence dat a for eight common alleles resulting from combinations of 9 out of the 12 S NP at IL4RA exon 11. Homo- or heterozygous combinations of these eight alle les accounted for all the IL4RA exon 11 genotypes found in Caucasian indivi duals from our geographical area.