Genomic organization of the IL4RA gene on chromosome 16p12 (not drawn to scale). The genomic organization of the gene was determined from the genomic (GenBank accession number AC004525) and cDNA sequences (Idzerda et al. 1990). Exons (E1–E9) are shown as rectangles, and introns (I1–I8) are shown as broken horizontal lines. The sizes of the exons and introns are as follows: E1, 70 bp; E2, 39 bp; E3, 152 bp; E4, 152 bp; E5, 157 bp; E6, 100 bp; E7, 79 bp; E8, 50 bp; E9, 1,579 bp; I1, 1,847 bp; I2, 2,609 bp; I3, 1,446 bp; I4, 5,920 bp; I5, 3,111 bp; I6, 3,007 bp; I7, 1,768 bp; and I8, 1,436 bp. Amino acid polymorphisms in the mature protein are shown. The polymorphism at amino acid 727 was reported in this study; others are from Deichmann and colleagues (Kruse et al. 1990; Deichmann et al. 1997) and Hershey et al. (1997).