Rapid Laboratory Diagnostic of X-Linked Ichthyosis

Abstract

Steroid sulfatase and aryl sulfatase C activities were assayed simultaneously in peripheral blood leucocytes of 4 patients with X-linked ichthyosis (XLI) and 4 patients with autosomal-dominant ichthyosis; 11 healthy subjects served as controls. The deficiency of steroid sulfatase as well as of aryl sufatase C found in leucocytes of patients with XLI was confirmed by the histochemical demonstration of aryl sulfatase C deficiency in skin sections. Although results are obtained earlier with the histochemical method than with the biochemical assay in leucocytes, several disadvantages brought us to the conclusion that the biochemical assay of microsomal sulfatase activity in leucocytes offers a fast and safe method for the identification of patients with XLI.

A fluorimetric assay of steroid sulphatase in leukocytes: Evidence for two genetically different enzymes with arylsulphatase C activity

“…This is in accordance with the incomplete inactivation of the STS locus of the inactive Xchromosome in females (Mohandas et al, 1980). Deficiency of total ASC activity in leukocytes from X-linked ichthyosis patients has been demonstrated (Meijer et al, 1982(Meijer et al, , 1986Herrmann et al, 1987). These authors found high residual activities up to 25% of normal activity.…”

“…It is commonly assayed using tritiated dehydroepiandrosterone sulphate (DHEAS) (for reviews see: Crawfurd, 1982;Taylor, 1982). The microsomal sulphatase activity measured with artificial substrates like p-nitrophenylsulphate (Milsom et al, 1972) or 4-methylumbelliferylsulphate (MUS) (Meijer et al, 1982) is defined as arylsulphatase C (ASC; EC 3.1.6.1) activity. It is still controversial whether STS and ASC activities represent a single enzyme (Rose, 1982) or that different enzymes have ASC activity (Chang et al, 1986).…”

Steroid Sulfatase = Aryl Sulfatase C? Chromatographic and Electrophoretic Properties in Extracts from Placental Microsomes and Skin Fibroblasts

“…More research effort will be necessary for the clarification of this situation. However, selecting the appro priate enzyme source (placental microsomes, cultured skin fibroblasts or leuko cytes), the deficiency of microsomal sulfa tase can be detected biochemically by both STS and ASC activity measurements [22],…”

“…Since the first observation by Jobsis et al [13] that boys born from sulfatase-deficient placentas develop an X-linked recessive ichthyosis (XRI), the link between microsomal sulfa tase deficiency -STS and ASC -and XRI has been confirmed by several groups all over the world [4,6,14,16,20,22,23,27], To our experience, using déhydroépian drostérone (DHEA) sulfate and 4-methylumbelliferone (MU) sulfate as substrates, STS as well as ASC activities were always simultaneously deficient in cultured skin fi broblasts and leukocytes [23] from patients with XRI. Though serveral attempts have been made, the question whether STS and ASC are identical or different enzymes is still not definitively answered [2,3,5,9,11,12,18,25,28].…”

X-Linked Recessive Ichthyosis

“…Immediately after arrival in Zurich, leukocytes were isolated by dextran sedimenta tion as described elsewhere [11,12] and then freezedried and stored at -20 °C until use. Arylsulfatase C (ASC) and steroid sulfatase (STS) activities, using 4-methylumbelliferone sulfate and 'H-dehydroepiandrosterone sulfate as substrates, respectively, were estimated as reported earlier [10,11].…”