Chromosomal organization of the RHCE and RHD genes according to the current understanding. The genes´ locus spans less than 450 kb on the short arm of chromosome 1 between the positions 1p34.3 and 1p36.13 (top). The physical distance between both genes is unknown. The RHD gene is located 3´ to the RHCE gene. The orientation of the genes in regard to each other and to the centromere is still unresolved. The genomic structure was analyzed for the RHCE gene {2843}. The RHD gene is believed to have a very similar structure (bottom). There are 37 amino acid positions varying between the Rhce and RHD alleles of both genes (thin lines in the 10 exons). The 3´ untranslated region (UTR) of exon 10 (hatched) covers more than 1,500 bp; a shorter stretch is known for RHCE, which deviated considerably (asterisks above 3´ UTR). Many of these exon polymorphisms have been utilized to detect the presence of the RHD allele. There is a 4,247 bp stretch of near nucleotide identity between the RHC and RHD alleles of both genes spanning from intron 1 to intron 2 (asterisks around exon 2). The positions of DNA insertions occuring in introns of the RHCE gene are indicated by arrows: All three insertions (109 bp in intron 2, 288 bp in intron 3 and 651 bp in the very short intron 4) have been utilized for DNA typing to detect the presence of the RHD allele.
 

see for review:
Transfus Med 8: 281 - 302, 1998
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last modified 17 Febr 1998