A CYP21A2 gene mutation in patients with congenital adrenal hyperplasia. Molecular genetics report from Saudi Arabia

Clinical analysis of 78 patients with nonclassical 21-hydroxylase deficiency

PURPOSE

Retrospectively analyze the clinical characteristics of patients with nonclassical 21-hydroxylase deficiency (NC21OHD) as well as the relationship between the gene mutations and endocrine hormones. In addition, the relationship between different basal 17-hydroxyprogesterone (17OHP) levels and patients' glucolipid metabolism, hormone levels, pregnancy, and treatment outcomes were examined.

METHODS

Clinical data of 78 females with NC21OHD from January 2012 to July 2022 in the Department of Endocrinology and Metabolism of the Third Affiliated Hospital of Guangzhou Medical University were retrospectively analyzed. Diagnosis was based on the 17OHP level combined with clinical manifestations, imaging, and other endocrine hormones and the cytochrome P450 c21, steroid 21-hydroxylase (CYP21A2) gene.

RESULTS

The age at diagnosis of the 78 patients was 29.1 ± 4.2 years; 83.3% (65/78) of the patients had menstrual abnormalities, 70 patients were of childbearing age, and 97.1% (68/70) had a history of infertility with a median time of infertility of 3.6 years. Moreover, 71.8% (56/78) of the patients had polycystic ovaries, 26.9% (21/78) had hyperandrogenemia manifestations on physical examination, 66.7% (52/78) had adrenal hyperplasia, 32.1% (25/78) had combined dyslipidemia, and 41.0% (32/78) had combined insulin resistance. Pathogenic mutations were detected in 78.2% (61/78) of the patients with both CYP21A2 alleles; 14.1% (11/78) of the patients had only one allele and 7.7% (6/78) had no pathogenic mutations. The levels of total testosterone (TT), progesterone (P) (0 min, 30 min), and 17-OHP (0 min, 30 min, 60 min) in the adrenocorticotropic hormone (ACTH) stimulation test varied between the groups. Furthermore, patients with NC21OHD were divided into 17OHP < 2 ng/ml, 2 ng/ml < 17OHP < 10 ng/ml, and 17OHP ≥ 10 ng/ml groups according to their different basal 17OHP levels. The 17OHP ≥ 10 ng/ml group had significantly higher TT, FT4, basal and post-stimulation progesterone, and 17OHP, net value added of 17-hydroxyprogesterone (△17OHP), net value added of 17-hydroxyprogesterone/net value added of cortisol ratio (△17OHP/△F), the incidence of adrenal hyperplasia, and number of gene mutations compared to those of the 17OHP < 2 ng/ml group (P < 0.05). NC21OHD infertile patients who received low-dose glucocorticoids showed a significant increase in pregnancy and live birth rates, and a significant decrease in miscarriage rate (all P < 0.05).

CONCLUSION

Comprehensive analysis is important as NCCAH diagnoses may be false positive or false negative based on clinical characteristics, hormone levels, and gene detection. Females with NC21OHD showed varying degrees of fertility decline; thus, low doses of glucocorticoid treatment for infertile females with NC21OHD can improve fertility and fertility outcomes.

Effect of the COVID-19 Pandemic on Treatment Adherence Among Children With Congenital Adrenal Hyperplasia

Background: This study determined the effect of the COVID-19 pandemic on adherence to medication among children with congenital adrenal hyperplasia (CAH) living in the Kingdom of Saudi Arabia (KSA).

Methods: Data were collected from April 2020 to April 2022 through face-to-face or telephonic interviews at a virtual paediatric endocrine clinic in Jeddah, KSA.

Results: A total of 55 children, with a mean age of 12.9 ± 5.8 years, participated in the study. Most children (32/55, 58%) were administered treatment by their mother. Before the COVID-19 pandemic, 51 patients (93%) reported adhering to their CAH treatment. After the onset of the COVID-19 pandemic, this number decreased to 49 (89%, p = 0.516). The most common reasons for non-adherence before and after the pandemic included restricted access to medication (supply and financial problems) and challenges in obtaining new prescriptions and refills. These challenges increased after the onset of the pandemic. Before and after the onset of the pandemic, mothers with a university degree were significantly more likely to administer medication than mothers without a university degree, but fathers’ education level did not affect their role in medication administration, before or after the onset of the pandemic.

Conclusion: This study confirms that the COVID-19 pandemic did not have a significant effect on medication adherence in children with CAH in Jeddah.

A Case of Salt-Wasting Congenital Adrenal Hyperplasia with Triple Homozygous Mutation: Review of Literature

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency represents a group of autosomal recessive disorders characterized by impaired cortisol production due to altered upstream steroid conversions, subclassified as classic and nonclassic forms. The genotype-phenotype correlation is possible in the most frequent case but not in all. Despite in literature many mutations are known, there is the possibility of finding a new genetic pattern in patients with CAH.

Genotype-Phenotype Correlation in Patients with Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency in Cuba

BACKGROUND

There are several studies that show a good genotype-phenotype correlation in congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD). However, there is well-documented evidence of inconsistency in some cases.

OBJECTIVES

To determine if there is a correlation between the identified mutations and the clinical manifestations of 21OHD in the Cuban population.

METHODS

A cross-sectional descriptive study of all patients referred for a molecular diagnosis of 21OHD in Cuba from January 2000 to December 2018. The clinical manifestations of each patient were identified and classified according to the phenotype. The CYP21A2 gene was analyzed for the presence of 5 point mutations involved in the pathogenesis of 21OHD (intron 2, deletion of 8bp, I172N, P30L, and Q318X); correlation was sought between the phenotypic characteristics and the frequencies of point mutations in the patients using the Spearman test.

RESULTS

A total of 55 patients underwent direct analysis of the CYP21A2 gene in order to determine the presence of the 5 point mutations. Point mutations were identified in 31 patients, which corresponded to 56%. A statistically significant genotype-phenotype correlation was found.

CONCLUSIONS

The correlation between the detected molecular defect and the clinical expression of 21OHD was reasonable in the Cuban population, which could allow phenotypic predictions to be made from the genotype.

Combined homozygous 21 hydroxylase with heterozygous P450 oxidoreductase mutation in a Saudi boy presented with hypertension

Congenital adrenal hyperplasia (CAH) comprises a group of inherited autosomal recessive disorders characterised by defective cortisol biosynthesis, compensatory increases in corticotrophin secretion and adrenocortical hyperplasia. The characteristics of the biochemical and clinical phenotype depend on the specific enzymatic defect. 21-hydroxylase deficiency is estimated to account for 90%-95% of all CAH cases. Although there are many variants of CAH, a new variant is found secondary to a mutation in the gene encoding the protein P450 oxidoreductase (POR) in which the electron is granted to all microsomal P450 enzymes type II. In 2004, it was discovered that this new CAH disease was attributable to the POR gene mutation. POR facilitates electron transfer from Nicotinamide adenine dinucleotide phosphate (NADPH) to key enzymes involved in steroid and sterol synthesis and metabolism. POR deficiency causes partial and combined impairment of the key enzymes involved in steroidogenesis: P450c17 (17α-hydroxylase/17,20 lyase), P450c21 (21-hydroxylase) and P450aro (aromatase). Clinically, mutant POR manifests with disordered sex development, adrenal insufficiency and skeletal malformations. However, each enzyme may be differently compromised in the same patient. This difference in the clinical manifestations secondary to the variability in enzymatic impairments ranges from ambiguous genitalia in both sexes, adrenal insufficiency associated or not to bone malformations, to abnormal laboratory results in the neonatal screening test of asymptomatic newborns. We report here a case of a 46, XY patient with normal male genitalia associated with hypertension not related to fludrocortisone in which genetic study showed that a homozygous mutation in the CYP21A2 also carries the heterozygous missense variant of unclear pathogenicity in the POR gene.Although there are many variants of CAH, a new variant is found secondary to a mutation in the gene encoding the protein P450 oxidoreductase (POR) which therefore the electron is granted to all microsomal P450 enzymes type II. In 2004, it was mentioned by Fluck and his colleagues that this new CAH disease was attributable to the POR gene mutation.POR facilitates electron transfer from NADPH to key enzymes involved in steroid and sterol synthesis and metabolism.POR deficiency causes partial and combined impairment of the key enzymes involved in steroidogenesis: P450c17 (17α- hydroxylase/17,20 lyase), P450c21 (21-hydroxylase) and P450aro (aromatase).Clinically, Mutant POR manifests with disordered sex development, adrenal insufficiency and skeletal malformations.However, each enzyme may be differently compromised in the same patient. This difference in the clinical manifestations secondary to the variability in enzymatic impairments, it is ranging from ambiguous genitalia in both sexes, adrenal insufficiency associated or not to bone malformations, to abnormal laboratory results in the neonatal screening test of asymptomatic newborns.

Issues with the Detection of Large Genomic Rearrangements in Molecular Diagnosis of 21-Hydroxylase Deficiency

More than 95% of congenital adrenal hyperplasia (CAH) cases are associated with mutations in the 21-hydroxylase gene (CYP21A2) in the human leukocyte antigen (HLA) class III area on the short arm of chromosome 6p21.3. In the diagnosis of 21-hydroxylase deficiency, CYP21A2 genotyping is a valuable complement to biochemical investigations. Genotyping can confirm the diagnosis (or carrier state) and, at the same time, provide accurate phenotype prediction in patients carrying severe mutations. In addition, the use of genetic testing is also helpful in prenatal diagnosis where the goal of prenatal treatment is preventing genital virilization of the female fetus. An in-depth knowledge of CYP21A2 genetics is essential to assure the correct interpretation of results obtained. To date, more than 200 small pathogenic variants of the CYP21A2 gene have been reported, showing good agreement between clinical phenotype and patient genotype. Recently, novel CYP21A2 deletions, involving one or more exons, have been reported in different populations. Since these rearrangements have never been described before in the genetic history of 21-hydroxylase deficiency, these new deletions have aroused particular interest. However, it is possible that these novel rearrangements are the result of incorrect interpretation of multiplex ligation-dependent probe amplification (MLPA).

Mutational analysis of rare subtypes of congenital adrenal hyperplasia in a highly inbred population

CONTEXT

Apart from 21 Hydroxylase deficiency, other subtypes of congenital adrenal hyperplasia (CAH) are rare. We studied the clinical features and molecular genetics of a relatively large series of patients with CYP17A1, HSD3β2 and StAR deficiencies.

PATIENTS AND METHODS

We studied 21 patients including 7 patients with CYP17A1, 10 patients with HSD3β2 and 4 patients with StAR deficiencies. For mutation detection, we isolated DNA from peripheral leucocytes, amplified genes of interest using polymerase chain reaction and directly sequenced the amplicons using Dideoxy Chain Termination method.

RESULTS

Regardless of their karyotype, patients with CYP17A1 deficiency presented with normally looking external female genitalia and were raised as females. Hypertension and hypokalemia were prominent features in 4 of 7 patients. Two missense (p.R416H, p.R239Q) and 2 non-sense (p.Y329X, p.Y329X) mutations were found in these 7 cases. In 3 unrelated families with 10 affected siblings with HSD3β2 mutations, two non-sense mutations were found (p.Q334X, p.R335X). 46XY patients with HSD3β2 deficiency presented with ambiguous genitalia while 46XX patients presented with normal female external genitalia. Adrenal crisis was common in patients with both karyotypes. In the 4 patients with StAR deficiency, both genetic male and female patients presented with normally looking female external genitalia and adrenal crisis. One previously reported missense mutation (p.R182H) was found in 3 unrelated patients and a novel non-sense mutation (p.Q264X) in the fourth patient.

CONCLUSIONS

These cases of rare subtypes of CAH illustrate the heterogeneous phenotypic and genetic features of these subtypes and add unique novel mutations to the previously known ones.

A unique haplotype of RCCX copy number variation: from the clinics of congenital adrenal hyperplasia to evolutionary genetics

There is a difficulty in the molecular diagnosis of congenital adrenal hyperplasia (CAH) due to the c.955C>T (p.(Q319*), formerly Q318X, rs7755898) variant of the CYP21A2 gene. Therefore, a systematic assessment of the genetic and evolutionary relationships between c.955C>T, CYP21A2 haplotypes and the RCCX copy number variation (CNV) structures, which harbor CYP21A2, was performed. In total, 389 unrelated Hungarian individuals with European ancestry (164 healthy subjects, 125 patients with non-functioning adrenal incidentaloma and 100 patients with classical CAH) as well as 34 adrenocortical tumor specimens were studied using a set of experimental and bioinformatic methods. A unique, moderately frequent (2%) haplotypic RCCX CNV structure with three repeated segments, abbreviated to LBSASB, harboring a CYP21A2 with a c.955C>T variant in the 3'-segment, and a second CYP21A2 with a specific c.*12C>T (rs150697472) variant in the middle segment occurred in all c.955C>T carriers with normal steroid levels. The second CYP21A2 was free of CAH-causing mutations and produced mRNA in the adrenal gland, confirming its functionality and ability to rescue the carriers from CAH. Neither LBSASB nor c.*12C>T occurred in classical CAH patients. However, CAH-causing CYP21A2 haplotypes with c.955C>T could be derived from the 3'-segment of LBSASB after the loss of functional CYP21A2 from the middle segment. The c.*12C>T indicated a functional CYP21A2 and could distinguish between non-pathogenic and pathogenic genomic contexts of the c.955C>T variant in the studied European population. Therefore, c.*12C>T may be suitable as a marker to avoid this genetic confound and improve the diagnosis of CAH.

Molecular Analysis of CYP21A2 Gene Mutations among Iraqi Patients with Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia is a group of autosomal recessive disorders. The most frequent one is 21-hydroxylase deficiency. Analyzing CYP21A2 gene mutations was so far not reported in Iraq. This work aims to analyze the spectrum and frequency of CYP21A2 mutations among Iraqi CAH patients. Sixty-two children were recruited from the Pediatric Endocrine Consultation Clinic, Children Welfare Teaching Hospital, Baghdad, Iraq, from September 2014 till June 2015. Their ages ranged between one day and 15 years. They presented with salt wasting, simple virilization, or pseudoprecocious puberty. Cytogenetic study was performed for cases with ambiguous genitalia. Molecular analysis of CYP21A2 gene was done using the CAH StripAssay (ViennaLab Diagnostics) for detection of 11 point mutations and >50% of large gene deletions/conversions. Mutations were found in 42 (67.7%) patients; 31 (50%) patients were homozygotes, 9 (14.5%) were heterozygotes, and 2 (3.2%) were compound heterozygotes with 3 mutations, while 20 (32.3%) patients had none of the tested mutations. The most frequently detected mutations were large gene deletions/conversions found in 12 (19.4%) patients, followed by I2Splice and Q318X in 8 (12.9%) patients each, I172N in 5 (8.1%) patients, and V281L in 4 (6.5%) patients. Del 8 bp, P453S, and R483P were each found in one (1.6%) and complex alleles were found in 2 (3.2%). Four point mutations (P30L, Cluster E6, L307 frameshift, and R356W) were not identified in any patient. In conclusion, gene deletions/conversions and 7 point mutations were recorded in varying proportions, the former being the commonest, generally similar to what was reported in regional countries.