| %300001 | ||||||
| ICHTHYOSIS, X-LINKED, WITHOUT STEROID SULFATASE DEFICIENCY | ||||||
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| The X-linked form of ichthyosis (308100) is the one most thoroughly studied after Koppe et al. (1977) observed a correlation between placental steroid sulfatase (STS) deficiency and the birth of males affected by this disorder. Shapiro et al. (1978) substantiated the finding by showing that cultured fibroblasts from unrelated patients with X-linked ichthyosis were deficient in steroid sulfatase activity, whereas patients with the autosomal form of ichthyosis had normal enzyme levels. Robledo et al. (1995) described a Sardinian kindred in which congenital ichthyosis was associated with normal levels of steroid sulfatase and a normal pattern on Southern blot analysis suggesting the presence of an intact STS gene. Although the pedigree pattern was entirely consistent with X-linked recessive inheritance, the ichthyosis was found to segregate independently of genetic polymorphisms detected by probes mapping to Xp22.3, where the STS locus maps. The search for linkage to markers elsewhere on the X chromosome had not been successful. Robledo et al. (1995) concluded that there may be a form of X-linked ichthyosis due to some mechanism other than STS deficiency. | ||||||
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