[Steroid sulfatase and placental deficiency. Current data as instigators of new research]

Arylsulfate sulfohydrolases, ubiquitously distributed, mediate the hydrolysis of sulfoconjugated steroids found in large amounts in a variety of human tissues and fluids. The sterol sulfate sulfohydrolase (steroid sulfatase), bound to the microsomal fraction, is capable of hydrolyzing natural substrates such as cholesterol and dehydroepiandrosterone sulfates. The placenta is the richest source of the enzyme. The physiological interest of this enzymatic activity became apparent when placental steroid sulfatase deficiency was described in pregnancies with strikingly low oestrogen levels in the maternal plasma and urine. This enzymopathy appears to have only a moderate pejorative incidence on the mode of delivery, thus intervention is unnecessary unless dictated by fetal and/or maternal associated pathology. The disorder is transmitted on the X-linked recessive mode of inheritance and affected individuals, all males, present with ichthyoses of the sex-linked type. The gene coding for the steroid sulfatase enzyme has been assigned to the distal part of the X-chromosome in the Xp22.3-Xpter region which is known to escape the inactivation process. The lack of enzymatic activity in the somatic tissues of the patients is followed by an increase of the circulating sulfated steroid levels and by an accumulation of cholesterol sulfate in blood and skin. The modified electrophoretic mobility of the low-density lipoproteins, which might result from the excess of cholesterol sulfate bound to these lipoproteins, is a new diagnostic clue for the enzymopathy. Apart from the modification recognized to be systematically associated to the steroid sulfatase deficiency, numerous cases of hypogonadism and cryptorchidism have been recently described and may be considered as new clinical manifestations of this genetic disorder. Recent cloning of the gene coding for the steroid sulfatase should allow the molecular study of the etiology of this inborn error of metabolism.