👤 M Delvecchio

Aim of this study is to report on basal clinical phenotype and follow up after diagnosis, of patients with 17beta-hydroxysteroid-dehydrogenase type 3 (17beta-HSD3) deficiency in Italy. Pediatric Endocrine Departments, University Hospitals. The cases of 5 Italian subjects affected by 17beta-HSD3 deficiency are presented in this study. Laboratory and genetic assessment. Gonadectomy and female sex assignment (4 patients) or GnRH analog therapy to regress puberty and gender identity disorder (1 patient). Presentation lasted from pregnancy (pre-natal diagnosis of a 46,XY fetus with female external genitalia) to infancy (inguinal hernia containing testes/clitoromegaly) and adolescence (virilisation). All subjects but one (subject 1, Central-Northern Italy) were from small areas of Southern Italy. Endocrine data (baseline and/or stimulated testosterone/ Delta4-androstenedione ratio) were informative. Two girls were homozygous for 17beta-HSD3 gene mutations (G289S/G289S; R80W/R80W), while the others were compound heterozygous (IVS325+4 A>T/A203V; L212Q/M235V; R80W/A235E). Four patients were confirmed as females and were well-adjusted with assigned sex; gender identity disorder improved during treatment with GnRH analog in the last subject. 17betaHSD3 deficiency may present from pregnancy to puberty for different clinical issues. Albeit testosterone/Delta4-androstenedione ratio represents the most accurate endocrine marker to diagnose the disorder, hCGstimulation is mandatory in pre-puberty. Molecular analysis of 17beta-HSD3 gene should be performed to confirm the diagnosis. Temporary GnRH analog treatment may regress gender identity disorder and provide time to confirm or change the birth sex assignment. Female individuals seems to be compliant with their sex, providing that virilisation does not occur. In Italy, the disorder seems to be more prevalent in the Southern regions and shows genetic heterogeneity. Show less

The 17beta-hydroxysteroid dehydrogenases (17betaHSD) gene family comprises different enzymes involved in the biosynthesis of active steroid hormones. The 17betaHSD type 3 (17betaHSD3) isoenzyme catalyzes the reductive conversion of the inactive C19-steroid, Delta4-androstenedione (Delta4- A), into the biologically active androgen, testosterone (T), in the Leydig cells of the testis. It is encoded by the 17beta-hydroxysteroid dehydrogenase type 3 (HSD17B3) gene, which maps to chromosome 9q22. Mutations in the HSD17B3 gene are associated with a rare form of 46,XY disorder of sex development referred to as 17betaHSD3 deficiency (or as 17-ketosteroid reductase deficiency), due to impaired testicular conversion of Delta4-A into T. 46,XY patients with 17betaHSD3 deficiency are usually classified as female at birth, raised as such, but develop secondary male features at puberty. Diagnosis, and consequently early treatment, is difficult because clinical signs from birth until puberty may be mild or absent. Biochemical diagnosis of 17betaHSD3 deficiency requires measurement of serum T/Delta4-A ratio after hCG stimulation test in pre-pubertal subjects, while baseline values seem to be informative in early infancy and adolescence. However, low basal T/Delta4-A ratio is not specific for 17betaHSD3 deficiency, being sometimes also found in patients with other defects in T synthesis or with Leydig cells hypoplasia. Mutational analysis of the 17HSDB3 gene is useful in confirming the clinical diagnosis of 17betaHSD3 deficiency. This review describes clinical findings, diagnosis, and molecular basis of this rare disease. Show less

Liver X receptor alpha (LXRalpha), an oxysterol-activated nuclear hormone receptor, regulates the expression of genes involved in lipid and cholesterol homeostasis and inflammation. We show here that transactivation by LXRalpha in monkey kidney COS-1 (Cos-1) cells is decreased by activation of the protein kinase C (PKC) signaling pathway. In transient co-transfection assays, phorbol myristate acetate (PMA) suppressed LXR-dependent transactivation of LXR-responsive reporter genes or the natural promoter of the human ATP-binding cassette (ABC), ABCA1 gene. The decrease in LXR transactivation after PMA treatment was also observed in human embryonic kidney (HEK) 293 and human hepatocellular carcinoma (HepG2) cells. Moreover, endogenous LXR target genes, ABCA1 and sterol response element-binding protein-1c, were also decreased by PMA treatment in HEK293 cells as assessed by real-time PCR. The PMA-mediated decrease of LXR activity was blocked by the PKC inhibitor bisindolylmaleimide and mimicked by constitutively active PKCalpha. Nuclear extracts treated with PMA show no decrease in LXRalpha DNA binding as assessed by mobility shift and chromatin immunoprecipitation assays. Additionally, in vitro kinase assays demonstrate that PKCalpha can phosphorylate LXRalpha. Our findings reveal a mode of regulation of LXRalpha that may be relevant to disease conditions where aberrant PKC signaling is observed, such as diabetes. Show less