title: Most "sporadic" cases of X-linked ichthyosis are not de novo mutations.
abstract: X-linked ichthyosis is an inherited disease with dark, regular and adherent scales as clinical characteristics. It is caused by a deficiency of the steroid sulphatase enzyme. Steroid sulphatase assay is a relative easy tool that enables correct diagnosis of X-linked ichthyosis patients and carriers. A large number of X-linked ichthyosis patients correspond to non-familial cases that seem to represent de novo mutations. In this study, we examined the X-linked ichthyosis carrier state of the mothers of 42 non-familial cases to determine whether their children corresponded to de novo mutations. To classify patients and carriers, a steroid sulphatase assay was performed in leukocytes using 7-[3H]-dehydroepiandrosterone sulphate as substrate. In 36 mothers (85%) we found steroid sulphatase activity compatible with the carrier state of X-linked ichthyosis. This data suggest that most of the mothers of these patients present the primary gene defect, excluding de novo mutations in the patients.
authors.affiliation: Department of Genetics, General Hospital of Mexico, DF, Mexico.
authors.forename: S A
authors.initials: SA
authors.lastname: Cuevas-Covarrubias
authors.forename: M
authors.initials: M
authors.lastname: Valdes-Flores
authors.forename: E
authors.initials: E
authors.lastname: Orozco Orozco
authors.forename: J C
authors.initials: JC
authors.lastname: Díaz-Zagoya
authors.forename: S H
authors.initials: SH
authors.lastname: Kofman-Alfaro
mesh_terms: D001192:Arylsulfatases / Q000097:blood* / Q000172:deficiency / Q000235:genetics; D005260:Female; D006801:Humans; D016114:Ichthyosis, X-Linked / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics*; D008297:Male; D009154:Mutation; D010375:Pedigree; D043266:Steryl-Sulfatase
chemical_list: D001192:Arylsulfatases; D043266:Steryl-Sulfatase