Variations in the promoter of CYP21A2 gene identified in a Chinese patient with simple virilizing form of 21-hydroxylase deficiency

Unexpectedly high mutation rate of cyp11b1 compared to cyp21a2 in randomly-selected turkish women: a large screening study

PURPOSE

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders resulting from enzyme deficiencies associated with steroidogenesis. The clinical presentation of non-classic CAH (NCAH) in females is often indistinguishable from other hyperandrogenic disorders like polycystic ovary syndrome (PCOS). The data on the prevalence of NCAH in unselected women in the literature is scanty. The research aimed to evaluate the prevalence of NCAH, carrier frequencies, and the correlation between clinical symptoms and genotype in Turkish women.

METHODS

The study group comprised two hundred and seventy randomly-selected unrelated asymptomatic women of reproductive age (18-45). Subjects were recruited from female blood donors. All volunteers underwent clinical examination and hormone measurements. The protein-encoding exons and exon-intron boundaries of the CYP21A2, CYP11B1, HSD3β2 and CYP21A2 promoter were sequenced by direct DNA sequencing.

RESULTS

After genotyping, seven (2.2%) individuals were diagnosed with NCAH. The heterozygous carrier frequencies of CYP21A2, CYP21A2 promoter, CYP11B1, and HSD3β2 genes with 34, 34, 41, and 1 pathologic mutation were determined at 12.6%, 12.6%, 15.2%, and 0.37% of volunteers, respectively. Gene-conversion (GC) frequencies between CYP21A2/CYP21A1P and CYP11B1/CYP11B2 were determined as 10.4% and 14.8%, respectively.

CONCLUSION

Despite GC-derived higher mutation frequency determined in the CYP11B1 gene, the reason for the low frequency of NCAH due to 11OHD compared to 21OHD might be that gene-conversion arises with active CYP11B2 rather than an inactive pseudogene. HSD3β1 exhibits high homology with HSD3β2 located on the same chromosome; remarkably, it demonstrates low heterozygosity and no GC, most probably the outcome of a tissue-specific expression pattern.

Nonclassic Adrenal Hyperplasia (NCAH) due to 21-hydroxylase deficiency: A cohort of 78 patients

Diagnosis of nonclassic adrenal hyperplasia (NCAH) due to 21-hydroxylase deficiency (21-OHD) may be challenging due to its occult manifestations. To characterize clinical and molecular features of NCAH patients due to 21-hydroxylase deficiency, we retrospectively included 78 NCAH patients. Their phenotype and genotype were presented and compared. The transcription activities of novel CYP21A2 promoter variants were investigated using a dual-reporter luciferase assay system. This cohort included 53 females (68 %) and 25 males (32 %). The median of onset age was 13 years old (female: 13 range from 7 to 38; male: 11 range from 6 to 71). Menstrual cycle disorder was the most common complaint in females (62 %, n = 33) and for males, it was adrenal incidentalomas (52 %, n = 13). A total of 17 (22 %) patients complained of infertility. The most frequently variant was p.Ile173Asn (20 %, n = 31). Importantly, five variants in the promoter region including - 103/- 126 and - 196/- 296 were found in 21 (27 %) patients. Patients with promoter variants showed older onset age and less impaired hormone levels of 17-hydroxyprogesterone, ACTH, progesterone, and androstenedione. Compared with the wild-type promoter, the basic transcription activity of - 103/- 126 and - 196/- 296 promoter variants were reduced by 57% and 25%, respectively. Therefore, females with menstrual cycle disorders or infertility and males with adrenal incidentaloma should be considered of NCAH due to 21-OHD. When genotyping patients with NCAH, the promoter region of the CYP21A2 gene should be also investigated.

The underlying cause of the simple virilizing phenotype in patients with 21-hydroxylase deficiency harboring P31L variant

OBJECTIVE

To analyze the relationship between genotype and phenotype in 21-Hydroxylase deficiency patients harboring P31L variant and the underlying mechanism.

METHODS

A total of 29 Chinese patients with 21-OHD harboring P31L variant were recruited, and the detailed clinical features of the patients were extracted and analyzed retrospectively. The TA clone combined with sequencing of the region containing the promotor and exon1 of CYP21A2 was performed to determine whether the variants in promotor and P31L aligned in cis. We further compared the clinical characteristics of 21-OHD patients between the promoter variant group and no promoter variant group.

RESULTS

Among the 29 patients diagnosed with 21-OHD harboring P31L variant, the incidence of classical simple virilizing form was 62.1%. Thirteen patients owned promoter variants (1 homozygote and 12 heterozygote) and all exhibited SV form. The promoter variants and the P31L variant were located in the same mutant allele as validated by TA cloning and sequencing. There were statistically significant differences in clinical phenotype and 17-OHP level between the patients with and without promoter region variations (P<0.05).

CONCLUSION

There exists high incidence (57.4%) of SV form among the 21-OHD patients harboring P31L variant, and the underlying mechanism is partially due to both the promoter variants and P31L aligning in cis on one allele. Further sequencing of promoter region will provide important hints for the explanation of phenotype in patients harboring P31L.

Genetic profiling of CAH Egyptian children: rapid guide to clinical interpretation of common mutations

OBJECTIVES

The prevalence of CAH in Egypt is reported to be ten times more than that of the worldwide prevalence. The study aimed at genetic screening of children diagnosed with 21-alpha hydroxylase deficiency congenital adrenal hyperplasia (21OHD-CAH). In addition, the study offers a rapid and easy guide for clinical reporting of common mutations for endocrinologists.

METHODS

A cohort of 174 unrelated Egyptian children with 21OHD-CAH were screened for 11 common CYP21A2 gene mutations using a strip hybridization assay, and then, bioinformatics analysis was done to report the pathogenicity of the common mutations for clinical classification.

RESULTS

The most common mutations were I2 splice and p.Q318X. Deletions/conversions comprised 45.9% of the cohort, whereas 7.4% of the cases were negative for all mutations. The least positively detected point mutations were p.P453S, cluster E6, p.R483P, and p.L307FS, which were detected in fewer than 5% of cases.

CONCLUSION

Strip hybridization assay is a rapid screening tool for the diagnosis of CAH. The authors hypothesized an easy and rapid scheme for clinical interpretation of the strip results to gain the highest value of the strip in diagnosis.

Clinical outcomes and characteristics of P30L mutations in congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Despite numerous studies in the field of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, some clinical variability of the presentation and discrepancies in the genotype/phenotype correlation are still unexplained. Some, but not all, discordant phenotypes caused by mutations with known enzyme activity have been explained by in silico structural changes in the 21-hydroxylase protein. The incidence of P30L mutation varies in different populations and is most frequently found in several Central and Southeast European countries as well as Mexico. Patients carrying P30L mutation present predominantly as non-classical CAH; however, simple virilizing forms are found in up to 50% of patients. Taking into consideration the residual 21-hydroxulase activity present with P30L mutation this is unexpected. Different mechanisms for increased androgenization in patients carrying P30L mutation have been proposed including influence of different residues, accompanying promotor allele variability or mutations, and individual androgene sensitivity. Early diagnosis of patients who would present with SV is important in order to improve outcome. Outcome studies of CAH have confirmed the uniqueness of this mutation such as difficulties in phenotype classification, different fertility, growth, and psychologic issues in comparison with other genotypes. Additional studies of P30L mutation are warranted.

EMQN best practice guidelines for molecular genetic testing and reporting of 21-hydroxylase deficiency

Molecular genetic testing for congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is offered worldwide and is of importance for differential diagnosis, carrier detection and adequate genetic counseling, particularly for family planning. In 2008 the European Molecular Genetics Quality Network (EMQN) for the first time offered a European-wide external quality assessment scheme for CAH (due to 21-OH deficiency). The interest was great and over the last years at about 60 laboratories from Europe, USA and Australia regularly participated in that scheme. These best practice guidelines were drafted on the basis of the extensive knowledge and experience got from those annually organized CAH-schemes. In order to obtain the widest possible consultation with practicing laboratories the draft was therefore circulated twice by EMQN to all laboratories participating in the EQA-scheme for CAH genotyping and was updated by that input. The present guidelines address quality requirements for diagnostic molecular genetic laboratories, as well as criteria for CYP21A2 genotyping (including carrier-testing and prenatal diagnosis). A key aspect of that article is the use of appropriate methodologies (e.g., sequencing methods, MLPA (multiplex ligation dependent probe amplification), mutation specific assays) and respective limitations and analytical accuracy. Moreover, these guidelines focus on classification of variants, and the interpretation and standardization of the reporting of CYP21A2 genotyping results. In addition, the article provides a comprehensive list of common as well as so far unreported CYP21A2-variants.

p.Gln318X and p.Val281Leu as the Major Variants of CYP21A2 Gene in Children with Idiopathic Premature Pubarche

Premature pubarche (PP) is the appearance of sexual hair in children before puberty. The PP phenotype may attribute to nonclassic congenital adrenal hyperplasia (NC-CAH). In this study, we investigated the role of CYP21A2 gene variants in patients with PP in the Iranian population. Forty patients (13 males and 27 females), clinically diagnosed with PP, were analyzed for molecular testing of CYP21A2 gene variants. Direct sequencing was performed for the samples. Also, gene dosage analysis was performed for the cases. Fourteen patients (35%) had a mutation of p.Gln318X and p.Val281Leu, out of which 10% had regulatory variants. Approximately 10% of the patients were homozygous (NC-CAH). 78.5% (11/14) of patients had trimodular RCCX of which 5 patients had two copies of CYP21A1P pseudogene. The prevalence of p.Val281Leu was higher than p.Gln318X in PP patients. In conclusion, CYP21A2 variant detection has implications in the genetic diagnosis of PP phenotype. The genetic characterization of the CYP21A2 gene is important for characterizing the variable phenotype of carriers and genetic counseling of PP and NC-CAH patients.

Variations in the 3'UTR of the CYP21A2 Gene in Heterozygous Females with Hyperandrogenaemia

Heterozygosity for CYP21A2 mutations in females is possibly related to increased risk of developing clinical hyperandrogenism. The present study was designed to seek evidence on the phenotype-genotype correlation in female children, adolescents, and women with CYP21A2 mutations and variants in the 3'UTR region of the gene. Sixty-six patients out of the 169 were identified as carriers of CYP21A2 mutations. Higher values of stimulated 17 hydroxyprogesterone (17-OHP) levels were found in the carriers of the p.Val281Leu mutation compared to the carriers of other mutations (mean: 24.7 nmol/l versus 15.6 nmol/l). The haplotype of the ∗52C>T, ∗440C>T, and ∗443T>C in the 3'UTR was identical in all heterozygous patients with p.Val281Leu and the haplotype of the ∗12C>T and ∗52C>T was identical in all heterozygous patients with the p.Gln318∗. In conclusion, hyperandrogenaemic females are likely to bear heterozygous CYP21A2 mutations. Carriers of the mild p.Val281Leu mutation are at higher risk of developing hyperandrogenism than the carriers of more severe mutations. The identification of variants in the 3'UTR of CYP21A2 in combination with the heterozygous mutation may be associated with the mild form of nonclassic congenital adrenal hyperplasia and reveal the importance of analyzing the CYP21A2 untranslated regions for the appropriate management of this category of patients.

A Case of Bilateral Testicular Tumors Subsequently Diagnosed as Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency

21-hydroxylase deficiency (21-OHD) caused congenital adrenal hyperplasia (CAH) is a group of autosomal recessive genetic disorders resulting from mutations in genes involved with cortisol (CO) synthesis in the adrenal glands. Testicular adrenal rest tumors (TARTs) are rarely the presenting symptoms of CAH. Here, we describe a case of simple virilizing CAH with TARTs, in a 15-year-old boy. The patient showed physical signs of precocious puberty. The levels of blood adrenocorticotropic hormone (ACTH), urinary 17-ketone steroids (17-KS), dehydroepiandrosterone sulfate (DHEA-S), and serum progesterone (PRGE) were elevated, whereas those of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and CO were reduced. Computed tomography (CT) of the adrenal glands and magnetic resonance imaging (MRI) of the testes showed a soft tissue density (more pronounced on the right side) and an irregularly swollen mass (more pronounced on the left side), respectively. Pathological examination of a specimen of the mass indicated polygonal/circular eosinophilic cytoplasm, cord-like arrangement of interstitial cells, and lipid pigment in the cytoplasm. Immunohistochemistry results precluded a diagnosis of Leydig cell tumors. DNA sequencing revealed a hackneyed homozygous mutation, I2g, on intron 2 of the CYP21A2 gene. The patient’s symptoms improved after a three-month of dexamethasone therapy. Recent radiographic data showed reduced hyperplastic adrenal nodules and testicular tumors. A diagnosis of TART should be considered and prioritized in CAH patients with testicular tumors. Replacement therapy using a sufficient amount of dexamethasone in this case helps combat TART.

Misregulation effect of a novel allelic variant in the Z promoter region found in cis with the CYP21A2 p.P482S mutation: implications for 21-hydroxylase deficiency

The aim of the current study was to search for the presence of genetic variants in the CYP21A2 Z promoter regulatory region in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Screening of the 10 most frequent pseudogene-derived mutations was followed by direct sequencing of the entire coding sequence, the proximal promoter, and a distal regulatory region in DNA samples from patients with at least one non-determined allele. We report three non-classical patients that presented a novel genetic variant-g.15626A>G-within the Z promoter regulatory region. In all the patients, the novel variant was found in cis with the mild, less frequent, p.P482S mutation located in the exon 10 of the CYP21A2 gene. The putative pathogenic implication of the novel variant was assessed by in silico analyses and in vitro assays. Topological analyses showed differences in the curvature and bendability of the DNA region bearing the novel variant. By performing functional studies, a significantly decreased activity of a reporter gene placed downstream from the regulatory region was found by the G transition. Our results may suggest that the activity of an allele bearing the p.P482S mutation may be influenced by the misregulated CYP21A2 transcriptional activity exerted by the Z promoter A>G variation.

Mutation analysis of the CYP21A2 gene in the Iranian population

BACKGROUND

Defects in the CYP21A2 gene cause steroid 21-hydroxylase deficiency, which is the most frequent cause of congenital adrenal hyperplasia. Forty four affected families were investigated to identify the mutation spectrum of the CYP21A2 gene.

METHODS

Families were subjected to clinical, biochemical, and molecular analyses. Allele-specific polymerase chain reaction amplification was used for eight common mutations followed by dosage analysis to exclude CYP21A2 deletions.

RESULTS

The most frequent mutations detected were gene deletions and chimera (31.8%). Other mutation frequencies were as follows: Q318X, 15.9%; I2G, 14.8%; I172N, 5.8%; gene duplication, 5.7%; R356W, 8%; and E6 cluster mutations, 2.3%. Direct sequencing of the CYP21A2 gene revealed R316X, P453S, c.484insT, and a change at the start codon. Different modules carried by patients were classified into five different haplotypes. The genotype phenotype correlation (positive predictive value) for group null, A, B, and C were 92.3%, 85.7%, 100%, and 0, respectively.

CONCLUSIONS

Methods used will be helpful for carrier detection and antenatal diagnosis, especially with inclusion of the multiplex ligation probe dependent amplification technique, which is easier for routine tests in comparison with other methods. Mutation frequencies indicate that Iranians are possible descendants of Asians and Europeans.

Metabolic disorders in newly diagnosed young adult female patients with simple virilizing 21-hydroxylase deficiency

Classical congenital adrenal hyperplasia (CAH) is characterized by the defects in cortisol and aldosterone secretion, and accompanied with adrenal hyperandrogenism. It is likely that the impaired adrenocortical function and intermittent treatment-related hypercortisolism may predispose patients to the development of metabolic syndrome in adulthood. Our aim was to assess the impact of hyperandrogenism on metabolic profiles in CAH women without glucocorticosteroid treatment. We evaluated the clinical characteristics and metabolic profiles in 30 untreated Chinese female adults with simple virilizing congenital adrenal hyperplasia (SV-CAH). Mutation analysis was performed by sequencing the entire 21-hydroxylase gene (CYP21A2). As compared with the controls, CAH patients had higher BMI (BMI, 21.5±2.1 vs. 20.0±1.8 kg/m2, P<0.05), higher 2 h post-load plasma glucose levels (6. 35±1.74 vs. 5. 35±1.17 mmol/l, P<0.05), higher serum triglycerides (TG) (1.12±0.64 vs. 0.63±0.15 mmol/l, P<0.01), and lower high-density lipoprotein cholesterol (HDL-c) (1.30±0.39 vs. 1.67±0.29 mmol/l, P<0.01). Moreover, CAH patients had higher fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) (1.81±0.99 vs. 1.24±0.50, P<0.05), while ΔIns30/ΔGlu30 showed no statistically significant difference in two groups. In addition, a marked reduction of serum adiponectin levels were observed in CAH patients (7.0±3.3 vs. 13.2±4.8 μg/ml, P<0.001), however, serum CRP levels were not different between patients and the controls. Further regression analysis showed that higher serum testosterone concentrations were associated with metabolic disorder indexes and reduction of serum adiponectin. Our study demonstrates that untreated CAH patients are prone to have metabolic disorders in association with elevated serum testosterone levels and reduced insulin insensitivity.