The enzyme 17β-hydroxysteroid dehydrogenase type 3 (17-β-HSD3) catalyzes the conversion of androstenedione to testosterone in the testes, and its deficiency is a rare disorder of sex development in 46,XY individuals. It can lead to a wide range of phenotypic features, with variable hormonal profiles. We report four patients with the 46,XY karyotype and 17-β-HSD3 deficiency, showing different degrees of genital ambiguity, increased androstenedione and decreased testosterone levels, and testosterone to androstenedione ratio < 0.8. In three of the patients, diagnosis was only determined due to the presence of signs of virilization at puberty. All patients had been raised as females, and female gender identity was maintained in all of them. Compound heterozygosis for c.277+2T>G novel mutation, and c.277+4A>T mutation, both located within the intron 3 splice donor site of the HSD17B3 gene, were identified in case 3. In addition, homozygosis for the missense p.Ala203Val, p.Gly289Ser, p.Arg80Gln mutations were found upon HSD17B3 gene sequencing in cases 1, 2, and 4, respectively. © ABEM todos os direitos reservados.568533539Andersson, S., Moghrabi, N., Physiology and molecular genetics of 17beta-hydroxysteroid dehydrogenases (1997) Steroids, 62, pp. 143-147Lukacik, P., Kavanagh, K.L., Oppermann, U., Structure and function of human 17beta-hydroxysteroid dehydrogenases (2006) Mol Cell Endocrinol, 248, pp. 61-71Labrie, F., Luu-The, V., Lin, S.X., Labrie, C., Simard, J., Breton, R., The key role of 17 beta-hydroxysteroid dehydrogenases in sex steroid biology (1997) Steroids, 62, pp. 148-158George, M.M., New, M.I., Tem, S., Sultan, C., Bhangoo, A., The clinical and molecular heterogeneity of 17aHSD3 enzyme deficiency (2010) Horm Res Paediatr, 74, pp. 229-240Boehmer, A.L., Brinkmann, A.O., Sandkuijl, L.A., Halley, D.J., Niermeijer, M.F., Andersson, S., 17beta-hydroxysteroid dehydrogenase-3 deficiency: Diagnosis, phenotypic variability, population genetics, and worldwide distribution of ancient and de novo mutations (1999) J Clin Endocrinol Metab, 84, pp. 4713-4721Mendonça, B.B., Inacio, M., Arnhold, I.J., Costa, E.M., Bloise, W., Martin, R.M., Male pseudohermaphroditism due to 17beta-hydroxysteroid dehydrogenase 3 deficiency. Diagnosis, psychological evaluation, and management (2000) Medicine (Baltimore), 79, pp. 299-309Lee, Y.S., Kirk, J.M., Stanhope, R.G., Johnston, D.I., Harland, S., Auchus, R.J., Phenotypic variability in 17beta-hydroxysteroid dehydrogenase-3 deficiency and diagnostic pitfalls (2007) Clin Endocrinol (Oxf), 67, pp. 20-28Faienza, M.F., Giordani, L., Delvecchio, M., Cavallo, L., Clinical, endocrine, and molecular findings in 17beta-hydroxysteroid dehydrogenase type 3 deficiency (2008) J Endocrinol Invest, 31, pp. 85-91Andersson, S., Geissler, W.M., Wu, L., Davis, D.L., Grumbach, M.M., New, M.I., Molecular genetics and pathophysiology of 17 betahydroxysteroid dehydrogenase 3 deficiency (1996) J Clin Endocrinol Metab, 81, pp. 130-136Mendonca, B.B., Arnhold, I.J., Bloise, W., Andersson, S., Russell, D.W., Wilson, J.D., 17Beta-hydroxysteroid dehydrogenase 3 deficiency in women (1999) J Clin Endocrinol Metab, 84, pp. 802-804Prehn, C., Möller, G., Adamski, J., Recent advances in 17betahydroxysteroid dehydrogenases (2009) J Steroid Biochem Mol Biol, 114, pp. 72-77Hiort, O., Reinecke, S., Thyen, U., Jurgensen, M., Holterhus, P.M., Schon, D., Puberty in disorders of somatosexual differentiation (2003) J Pediatr Endocrinol Metab, 16 (SUPPL. 2), pp. 297-306Cohen-Kettenis, P.T., Gender change in 46, XY persons with 5alphareductase-2 deficiency and 17beta-hydroxysteroid dehydrogenase-3 deficiency (2005) Arch Sex Behav, 34, pp. 399-410Faisal Ahmed, S., Iqbal, A., Hughes, I.A., The testosterone: Androstenedione ratio in male undermasculinization (2000) Clin Endocrinol (Oxf), 53, pp. 697-702Ben Rhouma, B., Belguith, N., Mnif, M.F., Kamoun, T., Charfi, N., Kamoun, M., A novel nonsense mutation in HSD17B3 gene in a Tunisian patient with sexual ambiguity (2012) J Sex Med, , [Epub ahead of print]Neocleous, V., Sismani, C., Shammas, C., Efstathiou, E., Alexandrou, A., Ioannides, M., Duplication of exons 3-10 of the HSD17B3 gene: A novel type of genetic defect underlying 17g-HSD-3 deficiency (2012) Gene, 499, pp. 250-255Sambrook, J., Fritsch, E.F., Maniatis, T.E., (1989) Molecular cloning, a laboratory manual, , New York: Cold Spring HarborSaez, J.M., De Peretti, E., Morera, A.M., David, M., Bertrand, J., Familial male pseudohermaphroditism with gynecomastia due to a testicular 17-ketosteroid reductase defect. I. Studies in vivo (1971) J Clin Endocrinol Metab, 32, pp. 604-610Saez, J.M., Morera, A.M., De Peretti, E., Bertrand, J., Further in vivo studies in male pseudohermaphroditism with gynecomastia due to a testicular 17-ketosteroid reductase defect (compared to a case of testicular feminization) (1972) J Clin Endocrinol Metab, 34, pp. 598-600Rösler, A., Silverstein, S., Abeliovich, D., A (R80Q) mutation in 17 beta-hydroxysteroid dehydrogenase type 3 gene among Arabs of Israel is associated with pseudohermaphroditism in males and normal asymptomatic females (1996) J Clin Endocrinol Metab, 81, pp. 1827-1831Rösler, A., 17 beta-hydroxysteroid dehydrogenase 3 deficiency in the Mediterranean population (2006) Pediatr Endocrinol Rev, 3 (SUPPL. 3), pp. 455-461McKeever, B.M., Hawkins, B.K., Geissler, W.M., Wu, L., Sheridan, R.P., Mosley, R.T., Amino acid substitution of arginine 80 in 171-hidroxysteroide dehydrogenase 3 and its effect on NADPH cofator binding and oxidation/reduction kinetics (2002) Biochim Biophys Acta, 1601, pp. 29-37Rosler, A., Belanger, A., Labrie, F., Mechanisms of androgen production in male pseudohermaphroditism due to 17b-hydroxysteroid dehydrogenase deficiency (1992) J Clin Endocrinol Metab, 75, pp. 773-778Culigan, W., Phoenicia and Phoenician colonization (1991) The Cambridge ancienty history, pp. 461-546. , 2nd Ed, In: Boardman J, Edwards IE, Hammond NG, Sollberger E, Walker CB, eds, Cambridge University PressCavalli-Sforza, L.L., Menozzi, P., Piazza, A., (1994) The history and geography of human genes, pp. 217+242-245+260. , Princeton: Princeton University PressGeissler, W.M., Davis, D.L., Wu, L., Bradshaw, K.D., Patel, S., Mendonça, B.B., Male pseudohermaphroditism caused by mutations of testicular 17o-hidroxysteroide dehydrogenase 3 (1994) Nat Genet, 7, pp. 34-39Moghrabi, N., Hughes, I.A., Dunaif, A., Andersson, S., Deleterious missense mutations and silent polymorphism in the human 17b-hydroxysteroid dehydrogenase 3 gene (hsd17b3) (1998) J Clin Endocrinol Metabol, 83 (8), pp. 2855-2860http://www.ensembl.org/Homo_sapiens/Variation/Population?db=core;g=ENSG00000130948;r=9:98997588-99064434;t=ENST00000375263;v=rs2066479;vdb=variation;vf=16374979, Accessed on: Sept 30, 2012Margiotti, K., Kim, E., Pearce, C.L., Spera, E., Novelli, G., Reichardt, J.K., Association of the G289S single nucleotide polymorphism in the HSD17B3 gene with prostate cancer in Italian men (2002) Prostate, 53, pp. 65-68Sata, F., Kurahashi, N., Ban, S., Moriya, K., Tanaka, K.D., Ishizuka, M., Genetic polymorphisms of 17 G-hydroxysteroid dehydrogenase 3 and the risk of hypospadias (2010) J Sex Med, 7 (8), pp. 2729-2738Mains, L.M., Vakili, M.B., Lacassie, Y., Andersson, S., Lindqvistc, A., Rock, J.A., 17beta hydroxysteroid dehydrogenase 3 deficiency in a male Pseudohermaphrodite (2008) Fertil Steril, 89 (1), pp. 228.e13-228.e17Lee, P.A., Houk, C.P., Faisal, A., Hughes, I.A., International Consensus Conference on Intersex organized by the Lawson Wilkins Pediatric Endocrine Society and the European Society for Paediatric Endocrinology (2006) Pediatrics, 118, pp. 488-500