MAPPING OF THE HSD17B2 GENE ENCODING TYPE-II 17-BETA-HYDROXYSTEROID DEHYDROGENASE CLOSE TO D16S422 ON CHROMOSOME 16Q24.1-Q24.2

The enzymes of the 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) gene family are responsible for a key step in the formation and degrad ation of androgens and estrogens: catalyzing the interconversion of 17 -ketosteroids and their active 17 beta-hydroxysteroid counterparts. Th e structure of human type II 17 beta-HSD cDNA was recently reported. T his enzyme catalyzes the interconversion of Delta(4)-androstenedione a nd testosterone, androstanedione and dihydrotestosterone, and estrone and 17 beta-estradiol, whereas type I 17 beta-HSD catalyzes exclusivel y the interconversion of estrogens. To locate the HSD17B2 gene, the no vel dinucleotide CA repeat sequence found 571 bp downstream from the e nd of exon 1 was genotyped into eight CEPH reference families by PCR. Two-point linkage analysis was performed between the latter polymorphi sm and the 2066 microsatellite markers of Genethon. The maximal pairwi se lod score (Z(max) = 33.3) with a maximal recombination fraction (th eta(max)) of 0.008 was obtained with the marker D16S422 located on 16q 24.1-q24.2. To define further the localization of the HSD17B2 gene, we constructed a high-resolution genetic map of the region flanking the polymorphic HSD17B2 gene including eight Genethon markers. The order o f the HSD17B2 gene and markers is qter-D16S516 - D16S504 - D16S507 - D 16S505 - D16S511 [HSD17B2 - D16S422] - D16S520 - D16S413-tel. (C)1995 Academic Press, Inc.