RESUMEN
OBJECTIVE: To describe the prenatal and postnatal diagnostic workup leading to the diagnosis of 5-alpha-reductase type 2 deficiency (5AR2D) in a case of 46,XY disorder of sex development (DSD). CASE REPORT: A first-trimester noninvasive prenatal test (NIPT) on maternal blood revealed a male fetus with a low risk of aneuploidy. However, a female fetus was identified at the second-trimester scan. A repeat sample revealed similar results and ruled out the possibility of both a sample swap or a vanishing twin. At birth, phenotypically female external genitalia were evident, with testes noted in the labioscrotal area. Neonatal blood confirmed a 46,XY complement and a 46,XY DSD genetic panel revealed a 5AR2D. CONCLUSION: Our case and others described in the literature demonstrate that fetal sex discordance detected by a combination of NIPT and subsequent ultrasound examination can be associated with several biological conditions, with DSD being the most significant.
Asunto(s)
3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa , Trastorno del Desarrollo Sexual 46,XY , 3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/deficiencia , 3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/genética , Trastorno del Desarrollo Sexual 46,XY/genética , Femenino , Genotipo , Humanos , Hipospadias , Masculino , Fenotipo , Embarazo , Diagnóstico Prenatal/métodos , Errores Congénitos del Metabolismo EsteroideoRESUMEN
Background: The 5α-reductase type 2 deficiency (5α-RD2) is a specific form of disorder of sexual development (DSD). Pathogenic variants in the SRD5A2 gene, which encodes this enzyme, are responsible for 46,XY DSD. Objective: The objective of the study was to investigate the genetic etiology of 46,XY DSD in two Mexican families with affected children. Materials and methods: The SRD5A2 gene of the parents and affected children was screened in both families via polymerase chain reaction amplification and DNA direct sequencing. The role of genetic variants in enzymatic activity was tested by site-directed mutagenesis. Results: Subject 1 presented two variants: p.Glu197Asp and p.Pro212Arg. Subject 2 was homozygous for the variant p.Glu197Asp. The two variants were reported in early studies. The directed mutagenesis study showed that the p.Glu197Asp and p.Pro212Arg variants lead to a total loss of enzymatic activity and, consequently, abnormal genitalia development in the patients. Conclusion: These results suggest that p.Glu197Asp and p.Pro212Arg are pathogenic variants that lead to the phenotypic expression of DSD. 5α-RD2 is of extreme importance not only because of its frequency (it is rare) but also because of its significance in understanding the mechanism of androgen action, the process of sexual differentiation, and the factors that influence normal sexual behavior.
RESUMEN
BACKGROUND AND OBJECTIVE: 5-Alpha reductase type 2 deficiency (5-ARD) is a rare disorder of sex development. The lack of 5-alpha reductase, an enzyme that converts testosterone into dihydrotestosterone, results in external genitalia that may appear female, or predominantly male, albeit undervirilized, or, more often, ambiguous. METHODS: This study describes a series of patients with 5-ARD raised as female, focusing on aspects related to gender identity. Following a retrospective chart review, patients with 5-ARD were invited to return to the clinic to enable their gender identity to be assessed using an 11-item structured in-house questionnaire. The Golombok-Rust Inventory of Sexual Satisfaction was applied to patients who had initiated their sexual life. RESULTS: Six patients aged >15 years with 5-ARD and raised as female were included. Most patients were diagnosed late: two before and four after puberty. The mean length of the phallus was 2.8 cm (0.5-5.0). Reasons for seeing a doctor included genital appearance (n = 3), amenorrhea/absence of breast development (n = 2), and changes in gender role attitudes (n = 1). According to the gender identity assessment, 4 patients identified as female, 1 as male, and 1 as both genders. Only the patient identified as male requested gender re-assignment. Of the two patients who had initiated their sexual life, sexual satisfaction was found to be good in one and poor in the other due to vaginal discomfort during intercourse. CONCLUSION: In the present series, the majority of undervirilized patients with a diagnosis of 5-ARD raised as female were in complete conformation with being female and described themselves as heterosexual. The more virilized patients were those least in conformity with their female-assigned gender.