High carrier frequency of a nonsense p.Trp230* variant in HSD3B2 gene in Ossetians.

Background: Congenital adrenal hyperplasia (CAH) caused by 3ß-HSD deficiency is a rare form of congenital adrenal deficiency with an autosomal recessive type of inheritance. Previously we have demonstrated that a single nucleotide variant (SNV) p.Trp230* in the homozygous state is a frequent cause of CAH among the indigenous population of North Ossetia-Alania represented by Ossetians. Methods: Genotyping of the NM_000198.3:c.690G>A p.Trp230* variant was performed by Real-time PCR. 339 healthy individuals of Ossetian origin were included in the study. Allele frequencies, Fisher's confidence intervals (CI) were calculated using the WinPepi v. 11.65 software. Comparison of allele frequencies was performed with the z-score test for two proportions. Results: Eight heterozygous carriers of c.690G>A variant in HSD3B2 gene were detected in 339 samples investigated. The total allele frequency of p.Trp230* variant was 0.0118 (n=8/678, 95% CI=0.0051-0.0231). Accordingly, the heterozygous carrier rate was 0.0236 (n=8/339). The frequency of CAH caused by p.Trp230* variant in HSD3B2 in Ossetian population was 1:7183 or 13.9 per 100,000 (95% CI: 1:1874-1:38447 or 3-53 per 100,000). Conclusion: The results demonstrate high frequency of p.Trp230* variant in Ossetians, which is most likely attributed to a founder effect.

A Founder Mutation in the POMC 5'-UTR Causes Proopiomelanocortin Deficiency Through Splicing-Mediated Decrease of mRNA.

CONTEXT: The syndrome of adrenal insufficiency, obesity, and red hair is a rare autosomal recessive disorder. The majority of disease-causing variants associated with the syndrome are located in the coding region of the POMC gene. OBJECTIVE: This work describes 7 unrelated patients who shared a novel homozygous mutation in the 5'-untranslated region (UTR) of the POMC gene and functionally characterize this novel variant. METHODS: Whole-exome sequencing (WES) with autozygosity mapping, Sanger sequencing, model expression system studies, and RNA sequencing were used for identification of the disease-causing variant and its subsequent functional characterization. Seven unrelated patients of the Perm Tatar ethnic group presented with hypoglycemia and excessive weight gain, low plasma adrenocorticotropin, and cortisol. Five of 7 children had red hair; 6 of 7 patients also showed signs of bronchial obstruction. RESULTS: WES showed shared autozygosity regions overlapping the POMC gene. Sanger sequencing of the POMC 5'-UTR detected a homozygous variant chr2:25391366C > T (hg19) at the splice donor site of intron 1. As demonstrated by the model expression system, the variant led to a significant decrease in the POMC messenger RNA level. Analyses of the patients' haplotypes were suggestive of the founder effect. We estimate that the mutation must have occurred at least 4.27 generations ago (95% CI, 0.86-7.67). CONCLUSION: This report presents a new molecular mechanism of POMC deficiency and contributes to the information on phenotypic variability in patients with this disorder.

[Clinical and molecular characteristics of patients with 46,XY DSD due to NR5A1 gene mutations].

Steroidogenic factor 1 (SF1, NR5A1) is a nuclear receptor that regulates multiple genes involved in adrenal and gonadal development, steroidogenesis, and the reproductive axis. Human mutations in SF1 were initially found in patients with severe gonadal dysgenesis and primary adrenal failure. However, more recent case reports have suggested that heterozygous mutations in SF1 may also be found in patients with 46,XY partial gonadal dysgenesis and underandrogenization but normal adrenal function. We have analyzed the gene encoding SF1 (NR5A1) in a cohort of 310 Russian patients with 46,XY disorders of sex development (DSD). Heterozygous SF1 variants were found in 36 out of 310 (11.6%) of cases, among them 15 were not previously described. We have not found any phenotype-genotype correlations and any clinical and laboratory markers that would allow to suspect this type of before conducting molecular genetic analysis.

[A clinical case of aromatase excess syndrome associated with 15Q21.2 duplication].

Aromatase excess syndrome (SIA) is a rare autosomal dominant disease caused by increased extraglandular conversion of androgens to estrogens. SIA is characterizedby early gonadotropin-independent hyperestrogenemia, causing pre-pubertal gynecomastia in boys and premature isosexual development in girls. Adults patients have short stature, due to the early closure of epiphyses because of hyperestrogenemia. Women usually have macromastia, endometrial hyperplastic processes and the late onset of menopause. In men, there is a moderate decrease of gonadotropins, leading to secondary hypogonadism. SIA in children can be suspected on a combination of the clinical picture of an excess of estrogens, increased levels of estrogens with low levels of gonadotropins after the exclusion of an estrogen-producing tumor. The frequency of occurrence of SIA is unknown, due to the rarity of the disease and the complexity of its molecular and genetic verification. In this article, we describe a clinical case of a 10-year-old patient with a late diagnosis of aromatase overactivity syndrome caused by a 15q21.2 microduplication of the CYP19A1 gene, and conduct a brief review of the literature.

[Dizygotic pregnancy as a possible mechanism of fetal gestation with a biallel mutation in the CYP11A1 gene: clinical case description].

One of the variants of congenital dysfunction of the adrenal cortex is a deficiency of the enzyme P450scc, which catalyzes the first stage of steroidogenesis. This is a rare autosomal recessive disease, the classic manifestation of which is primary adrenal insufficiency with a deficiency of gluco-and mineralocorticoids and a violation of the synthesis of sex steroids, which usually leads to a complete lack of masculinization in patients with karyotype 46, XY and hypergonadotropic hypogonadism in both sexes. Previously, it was suggested That p450scc deficiency is incompatible with the normal course of pregnancy, since the enzyme is expressed in the placenta, where it is necessary for the synthesis of progesterone, the main pregnancy hormone, and, consequently, the birth of a child with A p450scc deficiency is impossible. However, the literature describes clinical cases of p450scc deficiency with partially preserved enzyme function, which explains the normal course of pregnancy. Whereas cases of confirmed p450scc deficiency with zero enzyme activity are unique, not being explained until now. We present a description of severe p450scc deficiency in a child born from a dizygotic twin pregnancy in which the second Sib was healthy. It is possible that the preserved hormonal function of the second placenta and (or) treatment with progesterone analogs during gestation contributed to gestation in this rare form of steroidogenesis disorder.

A Novel Mutation in the Critical P-Box Residue of Steroidogenic Factor-1 Presenting with XY Sex Reversal and Transient Adrenal Failure.

BACKGROUND: Although the importance of steroidogenic factor-1 (SF1, NR5A1) for adrenal development is supported by numerous in vitro and in vivo studies, cases of SF1 deficiency associated with adrenal failure are exceptionally rare. The first human NR5A1 mutation was a heterozygous de novo p.G35E variant identified in a patient with disorder of sex development (DSD) 46,XY and primary adrenal insufficiency. Here we describe another association of the "classic" SF1 phenotype with a novel NR5A1 mutation affecting G35 residue. METHODS: We describe the clinical characteristics of a phenotypically female patient presenting at 2 months with signs of adrenal insufficiency. DSD 46,XY was diagnosed at 4 years. The NR5A1 gene was analyzed by Sanger sequencing. Minigene splicing and dual luciferase reporter assays were used to characterize effects of the novel mutation on splicing and transcription, respectively. RESULTS: Sequencing of the NR5A1 gene revealed a de novo heterozygous c.104G>A:p.G35D substitution. The minigene experiments demonstrated that c.104G>A substitution did not affect splicing. However, transactivation activity of the p.G35D mutant was clearly impaired, which was comparable with the effect of the p.G35E mutation. CONCLUSIONS: The findings stress the importance of G35 residue for adrenal development. The current observation also suggests that some patients with SF1 deficiency may present with transient adrenal failure.

Partial deficiency of 17α-hydroxylase/17,20-lyase caused by a novel missense mutation in the canonical cytochrome heme-interacting motif.

BACKGROUND: Deficiency of 17α-hydroxylase/17,20-lyase is a rare cause of 46,XY disordered sex development. OBJECTIVE: We characterize in vitro and in vivo effects of two novel CYP17A1 gene mutations identified in a patient with a mild phenotype of CYP17A1 deficiency. SUBJECTS AND METHODS: A 46,XY patient presented with ambiguous genitalia. CYP17A1 deficiency was suspected at 2 months on the basis of steroid analysis performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mutational analysis of the CYP17A1 gene was performed by PCR and Sanger sequencing. To characterize the effect of CYP17A1 mutation on 17α-hydroxylase and 17,20-lyase activities in vitro, HEK293 cells were transiently transfected with CYP17A1 expression plasmids, incubated with progesterone or 17-OH-pregnenolone and concentrations of 17-OH-progesterone or DHEA were then measured in the cell culture medium by LC-MS/MS. RESULTS: Clinical and hormonal findings in the patient were consistent with partial combined deficiency of 17α-hydroxylase/17,20-lyase. The sequencing of the CYP17A1 gene in the patient revealed compound heterozygosity for two novel mutations: c.107delT p.R36fsX107 and p.W121R. After 6-h in vitro culture of transfected HEK293 cells in the presence of 1 µM progesterone, 17α-hydroxylase activity of p.W121R mutant was 60.5±16.3%, while 17,20-lyase activity of mutant measured from the amount of DHEA produced in the presence of 1 µM of 17-OH-pregnenolone was 15.8±2.6% compared with the WT. CONCLUSIONS: p.W121R substitution, affecting the first residue in the conserved heme-interacting WXXXR motif of CYP17A1, is associated with partial combined deficiency of 17α-hydroxylase/17,20-lyase.