Reports

Non-inactivation of an x-chromosome locus in man

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Science  15 Jun 1979:
Vol. 204, Issue 4398, pp. 1224-1226
DOI: 10.1126/science.156396

Abstract

Cloned fibroblasts from women heterozygous for X-linked ichthyosis (steroid sulfatase deficiency) were examined to see whether or not this locus is subject to X-inactivation. Of 103 clones examined, all had normal levels of steroid sulfatase activity. Two of the women studied were also heterozygous for glucose-6-phosphate dehydrogenase deficiency. This allowed the demonstration that both X chromosomes were represented as the active X in various clones and that selection did not account for these findings. Thus, the steroid sulfatase locus, like the Xga locus to which it is linked, appears to escape X-inactivation in man.