Helena Campos Fabbri

The novel p.Cys65Tyr mutation in NR5A1 gene in three 46,XY siblings with normal testosterone levels and their mother with primary ovarian insufficiency

BackgroundDisorders of sex development (DSD) is the term used for congenital conditions in which development of chromosomal, gonadal, or phenotypic sex is atypical. Nuclear receptor subfamily 5, group A, member 1 gene (NR5A1) encodes steroidogenic factor 1 (SF1), a transcription factor that is involved in gonadal development and regulates adrenal steroidogenesis. Mutations in the NR5A1 gene may lead to different 46,XX or 46,XY DSD phenotypes with or without adrenal failure. We report a Brazilian family with a novel NR5A1 mutation causing ambiguous genitalia in 46,XY affected individuals without Müllerian derivatives and apparently normal Leydig function after birth and at puberty, respectively. Their mother, who is also heterozygous for the mutation, presents evidence of primary ovarian insufficiency.Case presentationThree siblings with 46,XY DSD, ambiguous genitalia and normal testosterone production were included in the study. Molecular analyses for AR, SRD5A2 genes did not reveal any mutation. However, NR5A2 sequence analysis indicated that all three siblings were heterozygous for the p.Cys65Tyr mutation which was inherited from their mother. In silico analysis was carried out to elucidate the role of the amino acid change on the protein function. After the mutation was identified, all sibs and the mother had been reevaluated. Basal hormone concentrations were normal except that ACTH levels were slightly elevated. After 1 mcg ACTH stimulation test, only the older sib showed subnormal cortisol response.ConclusionThe p.Cys65Tyr mutation located within the second zinc finger of DNA binding domain was considered deleterious upon analysis with predictive algorithms. The identification of heterozygous individuals with this novel mutation may bring additional knowledge on structural modifications that may influence NR5A1 DNA-binding ability, and may also contribute to genotype-phenotype correlations in DSD. The slightly elevated ACTH basal levels in all three patients with 46,XY DSD and the subnormal cortisol response after 1 mcg ACTH stimulation in the older sib indicate that a long-term follow-up for adrenal function is important for these patients. Our data reinforce that NR5A1 analysis must also be performed in 46,XY DSD patients with normal testosterone levels without AR mutations.

Long-term follow-up of an 8-year-old boy with insulinoma as the first manifestation of a familial form of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant hereditary cancer syndrome characterized mostly by parathyroid, enteropancreatic, and anterior pituitary tumors. We present a case of an 8-year-old boy referred because of hypoglycemic attacks. His diagnosis was pancreatic insulinoma. Paternal grandmother died due to repeated gastroduodenal ulcerations and a paternal aunt presented similar manifestations. At a first evaluation, the father presented only gastric ulceration but subsequently developed hyperparathyroidism and lung carcinoid tumor. During almost 15 years of follow-up, three brothers and the index case presented hyperparathyroidism and hyperprolactinemia. Molecular study showed a G to A substitution in intron 4, at nine nucleotides upstream of the splicing acceptor site, causing a splicing mutation. All affected members of the family have the same mutation. Paternal grandmother and aunt were not studied and the mother does not carry any mutation. MEN1 is a rare condition that requires permanent medical assistance. Early clinical and genetic identification of affected individuals is essential for their own surveillance and also for genetic counseling.

Multifunctional role of steroidogenic factor 1 and disorders of sex development

Disorders of sex development (DSD) involve several conditions that result from abnormalities during gonadal determination and differentiation. Some of these disorders may manifest at birth by ambiguous genitalia; others are diagnosed only at puberty, by the delayed onset of secondary sexual characteristics. Sex determination and differentiation in humans are processes that involve the interaction of several genes such as WT1, NR5A1, NR0B1, SOX9, among others, in the testicular pathway, and WNT4, DAX1, FOXL2 and RSPO1, in the ovarian pathway. One of the major proteins in mammalian gonadal differentiation is the steroidogenic nuclear receptor factor 1 (SF1). This review will cover some of the most recent data on SF1 functional roles and findings related to mutations in its coding gene, NR5A1.

Long-Term Follow-Up of Patients with 46,XY Partial Gonadal Dysgenesis Reared as Males

Background/Aims. Studies on 46,XY partial gonadal dysgenesis (PGD) have focused on molecular, gonadal, genital, and hormone features; little is known about follow-up. Our aim was to analyze long-term outcomes of PGD. Methods. Retrospective longitudinal study conducted at a reference service in Brazil. Ten patients were first evaluated in the 1990s and followed up until the 2010s; follow-up ranged from 13.5 to 19.7 years. All were reared as males and had at least one scrotal testis; two bore NR5A1 mutations. Main outcomes were: associated conditions, pubertal development, and growth. Results. All patients had normal motor development but three presented cognitive impairment; five had various associated conditions. At the end of the prepubertal period, FSH was high or high-normal in 3/6 patients; LH was normal in all. At the last evaluation, FSH was high or high-normal in 8/10; LH was high or high-normal in 5/10; testosterone was decreased in one. Final height in nine cases ranged from −1.57 to 0.80 SDS. All had spontaneous puberty; only one needed androgen therapy. Conclusions. There is good prognosis for growth and spontaneous pubertal development but not for fertility. Though additional studies are required, screening for learning disabilities is advisable.

Nr5a1 Loss-of-function Mutations Lead To 46,xy Partial Gonadal Dysgenesis Phenotype: Report Of Three Novel Mutations

Mutations in the NR5A1 gene, which encodes the steroidogenic factor 1 (SF1), are responsible for different phenotypes of disorders of sex development (DSD), such as bilateral anorchia and hypospadias. Furthermore, they can be associated with primary amenorrhea, premature ovarian failure, male infertility, adrenal tumors, and endometriosis. Direct sequencing of the 7 NR5A1 exons including ∼1,000 bp of the 5′-upstream and 3′-downstream regions and all intron-exon boundaries was performed in patients with DSD. Three different in silico tools were used to assess the consequences of a splice site mutation. As a result, 3 novel NR5A1 mutations were identified in 3 patients with 46,XY partial gonadal dysgenesis: p.Lys38* and p.Leu80Trpfs*8 lead to premature translation termination codons within the SF1 DNA-binding domain, and the intronic nucleotide substitution c.1138+1G>T at the intron 6 donor splice site is considered to modify correct splicing. We assume that the anomalous mRNA produced as a result of p.Lys38* and p.Leu80Trpfs*8 will be degraded by nonsense-mediated mRNA decay even before translation, leading to SF1 haploinsufficiency. The c.1138+1G>T mutation is expected to produce a truncated protein. Heterozygous SF1 loss-of-function mutations in these cases resulted in mild DSD manifestations, such as dysgenetic testes, spontaneous puberty, and preserved adrenal function.