Analysis of testosterone and dihydrotestosterone ratio in patients with 5alpha-reductase 2 deficiency and partial androgen insensitivity

• Grant number: 12/11233-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2012
• End date: August 31, 2013
• Field of knowledge: Health Sciences - Medicine - Maternal and Child Health
• Principal Investigator: Gil Guerra Júnior
• Grantee: Anna Beatriz Lima Do Valle Astur
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Since the normal male sex differentiation involves a greater number of events genetically determined than female sex differentiation, sex ambiguities (SA) and karyotype 46,XY presents a greater complexity to define the etiology. Among patients with disorders of sex development (DSD) 46,XY, the group with the normal production of testosterone is the most common and includes cases with 5±-reductase 2 deficiency and partial androgen insensitivity syndrome (PAIS). Clinically, the 5±-reductase 2 can be indistinguishable from the PAIS particularly in the absence of similar cases in the family when you can not evaluate the pattern of inheritance, and before puberty, in the absence of virilization and gynecomastia. The virilization during puberty and frequent change of psychosocial identification in patients 5±-reductase 2 deficiency, not gonadectomized before puberty, differently from the cases with PAIS, reinforce the importance of early diagnosis to choose the sex of rearing. The diagnosis of 5±-reductase 2 deficiency and PAIS is only confirmed by the identification of molecular changes in specific genes. Hormonal changes of testosterone (T) and dihydrotestosterone (DHT), serving as a screening test, are not always observed and the T and DHT ratio (T/DHT) suggest a diagnosis although this is not always changed. Therefore, the aim of this study is to compare the values of T/DHT ratio in patients with 5±-reductase 2 deficiency and PAIS in relation to patients with DSD 46,XY with unknown etiology. We will study patients with SA (presence of hypospadias and micropenis with or without cryptorchidism) with 46,XY karyotype and normal production of testosterone in the Outpatient Clinics of Interdisciplinary Group of Study of Sex Determination and Differentiation - UNICAMP who had a molecular study of genes SRD5A2 and AR performed. The following clinical data will be evaluated: age and gender, family history of SA, consanguinity, classification of the external genitalia, presence of palpable gonads. All non-pubertal patients will be evaluated with the stimulation test with hCG (1,500 IU/day for 3 consecutive days, IM) and serum basal of LH, FSH, T, and DHT and 24 hours after the last injection of hCG, levels of ²-hCG, T and DHT. In patients with spontaneous puberty will be made the only basal determination. Descriptive statistical analyzes will be done of the data, calculating the frequency (in absolute numbers and percentage), with the presentation of some results in table form. When necessary, for categorical variables, the chi-square test or Fisher's exact test will be done and the nonparametric Kruskal-Wallis test to assess whether there are differences in the T/DHT ratio between the three groups of patients. The significance level is 5%.(AU)