ABSTRACT
Steroidogenic factor-1 (SF1), encoded by the NR5A1 gene, is a key regulator of steroidogenesis and reproductive development. NR5A1 mutations described in 46,XY patients with disorders of sex development (DSD) can be associated with a range of conditions of phenotypes; however, the genotype-phenotype correlation remains elusive in many cases. In the present study, we describe the impact of five NR5A1 variants (three novel: p.Arg39Cys, p.Ser32Asn, and p.Lys396Argfs*34; and two previously described: p.Cys65Tyr and p.Cys247*) on protein function, identified in seven patients with 46,XY DSD. In vitro functional analyses demonstrate that NR5A1 mutations impair protein functions and result in the DSD phenotype observed in our patients. Missense mutations in the DNA binding domain and the frameshift mutation p.Lys396Argfs*34 lead to both, markedly affected transactivation assays, and loss of DNA binding, whereas the mutation p.Cys247* retained partial transactivation capacity and the ability to bind a consensus SF1 responsive element. SF1 acts in a dose-dependent manner and regulates a cascade of genes involved in the sex determination and steroidogenesis, but in most cases reported so far, still lead to a sufficient adrenal steroidogenesis and function, just like in our cases, in which heterozygous mutations are associated to 46,XY DSD with intact adrenal steroid biosynthesis.
Subject(s)
Disorder of Sex Development, 46,XY/diagnosis , Disorder of Sex Development, 46,XY/genetics , Mutation , Phenotype , Steroidogenic Factor 1/genetics , Adolescent , Alleles , Amino Acid Substitution , Child , Child, Preschool , Female , Genetic Association Studies , Genotype , Humans , Infant , Infant, Newborn , Male , Models, Molecular , Protein Conformation , Sequence Analysis, DNA , Steroidogenic Factor 1/chemistry , Structure-Activity Relationship , Young AdultABSTRACT
OBJECTIVE: To describe the profile of patients with genitourinary abnormalities treated at a tertiary hospital genetics service. METHODS: Cross-sectional study of 1,068 medical records of patients treated between April/2008 and August/2014. A total of 115 cases suggestive of genitourinary anomalies were selected, regardless of age. A standardized clinical protocol was used, as well as karyotype, hormone levels and genitourinary ultrasound for basic evaluation. Laparoscopy, gonadal biopsy and molecular studies were performed in specific cases. Patients with genitourinary malformations were classified as genitourinary anomalies (GUA), whereas the others, as sex differentiation disorders (SDD). Chi-square, Fisher and Kruskal-Wallis tests were used for statistical analysis and comparison between groups. RESULTS: 80 subjects met the inclusion criteria, 91% with SDD and 9% with isolated/ syndromic GUA. The age was younger in the GUA group (p<0.02), but these groups did not differ regarding external and internal genitalia, as well as karyotype. Karyotype 46,XY was verified in 55% and chromosomal aberrations in 17.5% of cases. Ambiguous genitalia occurred in 45%, predominantly in 46,XX patients (p<0.006). Gonadal differentiation disorders accounted for 25% and congenital adrenal hyperplasia, for 17.5% of the sample. Consanguinity occurred in 16%, recurrence in 12%, lack of birth certificate in 20% and interrupted follow-up in 31% of cases. CONCLUSIONS: Patients with SDD predominated. Ambiguous genitalia and abnormal sexual differentiation were more frequent among infants and prepubertal individuals. Congenital adrenal hyperplasia was the most prevalent nosology. Younger patients were more common in the GUA group. Abandonment and lower frequency of birth certificate occurred in patients with ambiguous or malformed genitalia. These characteristics corroborate the literature and show the biopsychosocial impact of genitourinary anomalies.
