X-linked ichthyosis is an inherited disease with dark, regular and adherent
scales as clinical characteristics. It is caused by a deficiency of the st
eroid sulphatase enzyme. Steroid sulphatase assay is a relative easy tool t
hat 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 cas
es to determine whether their children corresponded to de novo mutations. T
o classify patients and carriers, a steroid sulphatase assay was performed
in leukocytes using 7-[H-3]-dehydroepiandrosterone sulphate as substrate. I
n 36 mothers (85%) we found steroid sulphatase activity compatible with the
carrier state of X-linked ichthyosis. This data suggest that most of the m
others of these patients present the primary gene defect, excluding de novo
mutations in the patients.