New mutations, hotspots, and founder effects in Brazilian patients with steroid 5 alpha-reductase deficiency type 2

Mutations of the steroid 5 alpha-reductase type 2 (SRD5A2) gene in 46,XY subjects cause masculinization defects of varying degrees, due to reduced or impaired enzymatic activity. In this study, sequence abnormalities of the SRD5A2 gene were assessed by polymerase chain reaction with specific primers and automated sequencing analysis in DNA samples from 20 patients with suspected steroid 5 alpha-reductase type 2 deficiency from 18 Brazilian families. Eleven subjects presented SRD5A2 homozygous single-base mutations (two first cousins and four unrelated patients with G183S, two with R246W, one with del642T, one with G196S, and one with 217_218insC plus the A49T variant in heterozygosis), whereas four were compound heterozygotes (one with Q126R/IVS3+1G > A, one with Q126R/del418T, and two brothers with Q126R/G158R). Three patients were heterozygous for A207D, G196S, and R266W substitutions. The V89L polymorphism was found in heterozygosis in one of them (with A207D) and in one case with an otherwise normal gene sequence. The A49T variant was also detected in heterozygosis in the second case without other sequencing abnormalities. Four patients harbor yet non-described SRD5A2 gene mutations: a single nucleotide deletion (del642T), a G158R amino acid substitution, a splice junction mutation (IVS3+1G > A), and the insertion of a cytosine (217_218insC) occurring at a CCCC motif. This is the first report of a single-nucleotide insertion in the coding sequence of the SRD5A2 gene. In addition to these new mutations, this investigation reveals the prevalence of G183S substitution among a subset of African-Brazilian patients and presents evidences of the recurrence of already known mutations.83756957

Diagnosis of 5 alpha-reductase type 2 deficiency: Contribution of anti-Mullerian hormone evaluation

Aim: To evaluate anti-Mullerian hormone (AMH) levels in patients with clinical and molecular diagnosis of 5 alpha-reductase 2 deficiency. Patients and Methods: Data from 14 patients whose age ranged from 21 days to 29 years were analyzed according to age and pubertal stage. Sexual ambiguity was rated as Prader III in 11 patients. LH, FSH, testosterone (T), dihydrotestosterone (DHT) and AMH serum levels were measured in all but two patients, who had been previously submitted to gonadectomy; T and DHT were also measured in 20 age-matched controls. Results: Gonadotropin levels were normal in all but one patient who retained gonads (six of whom had reached puberty) and T/DHT ratio was elevated in all patients when compared to controls. All prepubertal patients had AMH levels < -1 SD for age, while most pubertal patients had AMH levels compatible with pubertal stage. Conclusions: Prepubertal patients with 5 alpha-reductase 2 deficiency have AMH values in the lower part of the normal range. These data indicate that T does not need to be converted to DHT to inhibit AMH secretion by Sertoli cells.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.18121383138

Evaluation of the tubular and interstitial functions of the testis in 46,XY patients with ambiguous genitalia

Investigation of the origin of sexual ambiguity is complex. Although testicular function has traditionally been assessed only by examining the steroidogenic capacity of Leydig cells and spermatogenesis, it has recently been shown that the measurement of serum anti-Mullerian hormone (AMH) as a marker of Sertoli cell function may also help clinicians. The aim of this study was to evaluate both Leydig and Sertoli cell functions in 46,XY patients with intersex states in order to establish biochemical patterns that would help to reach an etiologic diagnosis. We measured serum androgens, AMH and gonadotropins in 24 patients with sexual ambiguity and XY karyotype: 8 with gonadal dysgenesis (GD), 3 with 3 beta-hydroxy-steroid dehydrogenase deficiency (3 beta HSD), 5 with androgen insensitivity syndrome (AIS), 4 with 5 alpha-reductase 2 (SRD5A2) deficiency, and 4 were of unknown origin or idiopathic, Our results showed that while testosterone was low and gonadotropins elevated in patients with either GD or 3 beta HSD, AMH was low in the former and high in the latter. Serum AMH and gonadotropins were normal or high in patients with 3 beta HSD or AIS, but these could be distinguished by testosterone levels. Serum testosterone and gonadotropins were normal or high in AIS and SRD5A2 deficiency patients; however, while AMH was elevated in AIS, it was not the case in SRD5A2 deficiency patients, indicating that testosterone is sufficient to inhibit AMH within the testis. In idiopathic cases gonadotropins and testosterone were normal, and AMH was normal or low. We conclude that the combined measurement of androgens, AMH and gonadotropins helps to establish the diagnosis in intersex patients.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.13660561