Assignment of the gene for adrenal p450cl7 (steroid 17α-hydr0xylase/17,20 lyase) to human chromosome 10

P450cl7 is the single enzyme mediating both 17α-hydroxylase and 17,20 lyase activities. We identified several human P450cl7 cDNA clones in a human adrenal cDNA library we constructed in XgtlO. A short clone containing the 3’-terminal 650 bases of the full-length sequence was used to examine Southern blots of DNA from normal persons and from a panel of mouse/human somatic cell hybrid lines. The pattern of hybridization of this cDNA to normal human DNA cut with 8 restriction endonucleases suggests the human genome has two (or more) P450cl7 genes. The pattern of hybridization to the somatic cell hybrid cell lines, each containing a limited, known number of human chromosomes, indicates the human adrenal P450cl7 gene lies on chromosome 10. The chromosomal locations of the other P450cl7 genes could not be determined.