Characterization of the CYP21A2 Gene Mutations in Children with Classic Congenital Adrenal Hyperplasia

OBJECTIVE

To characterize the CYP21A2 gene mutations in children with classic congenital adrenal hyperplasia (CAH).

METHODS

A prospective, cross-sectional study was conducted on 24 children with classic CAH. Molecular characterization of the CYP21A2 gene was carried out by Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), or clinical exome sequencing. Another 21 previously mutation-proven CAH patients were also included and a combined result was drawn.

RESULTS

Out of 45 children, pathogenic variants in the CYP21A2 gene were identified in 43 patients (95.5%). Homozygous, probable compound heterozygous, and heterozygous variants were seen in 69%, 22%, and 18% of patients, respectively. The most common variant was c.293-13C/A>G (33%), followed by deletion/duplication (24%), and c.955C>T (p.Gln319Ter) (21%), similar to previous Indian studies. Allelic frequencies of c.332_339del and c.518 T>A (p.Ile173Asn) were 9% and 4%, respectively. Less common variants were c.923dupT (p.Leu308PhefsTer6), c.92C>T (p.Pro31Leu), c.1069C>T (p.Arg357Trp), c.1267G>C (p.Gly423Arg), and c.710_719delins (p.Ile237_Met240delinsAsnGluGluLys). A good genotype-phenotype correlation was observed; only p.Pro31Leu and p.Ile173Asn variants showed discordance. The diagnostic yield of Sanger sequencing alone, Sanger sequencing with MLPA, and clinical exome alone was 85%, 100%, and 100%, respectively.

CONCLUSIONS

All children, except two, diagnosed clinically as classic CAH, showed pathogenic variants in the CYP21A2 gene; the most common variant was c.293-13 C/A>G. The results suggest a broad mutation spectrum in the authors' single-center cohort of children with CAH. Clinical exome sequencing is the preferred stand-alone method for molecular diagnosis of CAH.

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.

Congenital adrenal hyperplasia with a CYP21A2 deletion overlapping the tenascin-X gene: an atypical presentation

OBJECTIVES

Congenital Adrenal Hyperplasia (CAH) is a group of genetic diseases characterized by impaired cortisol biosynthesis. 95% of CAH cases result from mutation in the CYP21A2 gene encoding 21-hydroxilase. TNX-B gene partially overlaps CYP21A2 and encodes a matrix protein called Tenascin-X (TNX). Complete tenascin deficiency causes Enlers-Danlos syndrome (EDS). A mono allelic variant called CAH-X CH-1 was recently described, resulting from a CYP21A2 complete deletion that extends into the TNXB. This haploinsufficiency of TNX may be associated with a mild hypermobility form of EDS, as well as other connective tissue comorbidities such as hernia, cardiac defects and chronic arthralgia.

CASE PRESENTATION

We report four patients heterozygous for a CAH-X CH-1 allele that do not present clinical manifestations of the EDS.

CONCLUSIONS

All CAH patients, carriers of these TNXA/TNXB chimeras, should be evaluated for clinical manifestations related to connective tissue hypermobility, cardiac abnormalities and other EDS features, allowing for better clinical surveillance management.

Genetic analysis and novel variation identification in Chinese patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Congenital adrenal hyperplasia owing to 21-hydroxylase deficiency is an autosomal-recessive disorder caused by mutations in the CYP21A2 gene. The aim of the study was to analyze the molecular data of 155 21-OHD patients and retrospectively investigated the common allelic mutations of CYP21A2 in 1442 Chinese 21-OHD patients. Clinical features and mutations of CYP21A2 gene in 155 unrelated 21-OHD patients were examined. Of the 155 patients, 103 cases were salt-wasting (SW) forms, 38 were simple virilizing (SV) forms and 14 were non-classical (NC) forms. In general, two types of mutations including common allelic mutations (281/310, 90.6%) and rare mutations (29/310, 9.4%) were detected, among them four novel variants c.835G>T, c.1081C>T, c.1423C>T and c.651 + 2 T > G were identified. In 1442 Chinese 21-OHD patients, the most frequently mutations were I2G (36.2%), large deletion/conversion (20.7%) and p.I173N (17.8%), while p.V282L has the lowest frequency. In this study, we provided detailed clinical data and mutation spectrum in Chinese 21-OHD patients. Moreover, four novel CYP21A2 variants (c.835G>T, c.1081C>T, c.1423C>T and c.651 +2 T > G) were identified and computational structural modeling indicated that these novel variations probably affect structural stability. Our findings improve the understanding of CYP21A2 mutational spectrum and contribute to the precise diagnosis and prenatal counseling.

Molecular Diagnosis of Steroid 21-Hydroxylase Deficiency: A Practical Approach

Adrenal insufficiency in paediatric patients is mostly due to congenital adrenal hyperplasia (CAH), a severe monogenic disease caused by steroid 21-hydroxylase deficiency (21-OHD, encoded by the CYP21A2 gene) in 95% of cases. CYP21A2 genotyping requires careful analyses that guaranty gene-specific PCR, accurate definition of pseudogene-gene chimeras, gene duplications and allele dropout avoidance. A small panel of well-established disease-causing alterations enables a high diagnostic yield in confirming/discarding the disorder not only in symptomatic patients but also in those asymptomatic with borderline/positive results of 17-hydroxyprogesterone. Unfortunately, the complexity of this locus makes it today reluctant to high throughput techniques of massive sequencing. The strong relationship existing between the molecular alterations and the degree of enzymatic deficiency has allowed genetic studies to demonstrate its usefulness in predicting/classifying the clinical form of the disease. Other aspects of interest regarding molecular studies include its independence of physiological variations and analytical interferences, its usefulness in the diagnosis of simple virilizing forms in males and its inherent contribution to the genetic counseling, an aspect of great importance taking into account the high carrier frequency of CAH in the general population. Genetic testing of CYP21A2 constitutes an irreplaceable tool to detect severe alleles not just in family members of classical forms but also in mild late-onset forms of the disease and couples. It is also helpful in areas such as assisted reproduction and preimplantation diagnosis. Molecular diagnosis of 21-OHD under expert knowledge definitely contributes to a better management of the disease in every step of the clinical course.

Non-Classical 21-Hydroxylase Deficiency: Analysis of a Mutant Gene in a Uyghur Family and Literature Review

OBJECTIVE

The gene mutation and clinical characteristics of a patient with non-classical 21-hydroxylase deficiency and his family were analyzed.

METHODS

A patient was diagnosed with non-classical 21-hydroxylase deficiency in the Department of Endocrinology of People's Hospital of Xinjiang Uygur Autonomous Region in December 2016. The clinical data and related gene-sequencing results were analyzed. The detected mutations were verified in nine members of the family.

RESULTS

Gene-sequencing results revealed that the proband and the other three members of the family (proband, proband's mother's younger brother and the proband's mother's younger brother's younger daughter, and proband's second elder sister) shared the following mutations: Ile173Asn, Ile237Asn, Val238Glu, Met240Lys, Val282Leu, Leu308Phefs*6, Gln319Ter, Arg357Trp, and Arg484Profs. The Val282Leu mutation was heterozygous in the proband's mother's younger brother's younger daughter, but homozygous in the other three individuals. The father of the proband, the elder brother of the father of the proband, the third younger brother of the father of the proband, and the elder sister of the proband all carried only the Val282Leu mutation.

CONCLUSION

Val282Leu is the gene responsible for non-classical 21-hydroxylase deficiency. Screening for this gene in the offspring of patients with non-classical 21-hydroxylase deficiency may help to identify cases early.

Comprehensive Genetic Testing of CYP21A2: A Retrospective Analysis in Patients with Suspected Congenital Adrenal Hyperplasia

The most common form of congenital adrenal hyperplasia (CAH) results from a deficiency of the 21-hydroxylase enzyme (21-OHD), presenting with a broad spectrum of clinical phenotypes according to the CYP21A2 gene mutations. Of the 59 patients with suspected CAH, 62.7% presented a positive genetic result. Of them, 78.4% and 18.9% presented with non-classical and classical forms, respectively. An overall phenotype-genotype correlation of 88.9% was observed. Biochemically, 17-hydroxiprogesterone concentrations were significantly higher in genetically confirmed patients. Genetically, 36 patients presented with previously reported pathogenic variants, and one presented a new variant in homozygosis. Among the 74 alleles tested, point mutations were found in 89.2% and large rearrangements were found in the rest. The most prevalent pathogenic variant was p.(Val282Leu). The inclusion of relatives revealed one further case. Interestingly, 87.5% of relatives were carriers of a pathogenic variant, including two siblings initially classified as genetically positive. In addition, the study of male partners with gestational desire identified several carriers of mild mutations. Studying the allelic distribution of the variants also allowed for reclassifying one patient. In conclusion, a genetic approach including Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA) analysis, and allelic distribution of the pathogenic variants represents a beneficial tool for better classifying patients with 21-OHD.

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.

The spectrum of CYP21A2 gene mutations in patients with classic salt wasting form of 2l-hydroxylase deficiency in a Chinese cohort

Background

21‐Hydroxylase deficiency (21‐OHD) caused by the CYP21A2 gene mutations is the most common form of congenital adrenal hyperplasia. It is an autosomal recessive disorder that results in defective synthesis of cortisol and aldosterone. The incidences of various CYP21A2 gene mutations and the genotype–phenotype correlations vary among different populations.

Materials and Methods

The clinical and molecular data of 22 patients were analyzed in this study. All patients were recruited from the neonatal intensive care unit. Locus‐specific polymerase chain reaction and Sanger sequencing were applied to identify gene micro‐conversions, and multiplex ligation‐dependent probe amplification was used to detect large fragment deletions/conversions. Then, the genotypes were categorized in to Null, A, B, C, and D groups to analyze the relationships between genotypes and phenotypes.

Results

All 22 patients were classified into classic salt wasting form of 21‐OHD. Molecular defects were detected in 44 alleles (100%). Micro‐conversion mutation IVS2‐13A/C>G (70.5%) is most common in our cohort, followed by large gene deletions and conversions (22.7%). The other mutations present were p.R357 W (4.5%) and E6 Cluster (2.3%). Genotypes of 22 patients (100%) were consistent with the predictive phenotypes.

Conclusion

In this study, we identified the mutation spectrum of CYP21A2 gene in Chinese patients, especially the younger age cohort in pediatrics. Micro‐conversions were the most popular mutations. Moreover, the genotypes and phenotypes were well correlated in this cohort of salt wasting 21‐OHD recruited from neonatal intensive care unit.

We identified the mutation spectrum of CYP21A2 gene in Chinese patients, especially the younger age cohort admitted in NICU. The genotypes and phenotypes in 21‐OHD were well correlated.

The prevalence of heterozygous CYP21A2 deficiency in patients with idiopathic acne, hirsutism, or both

PURPOSE

The purpose of this study is to assess the prevalence of heterozygous CYP21A2 mutation and analyze its correlation with clinical manifestation in patients with acne, hirsutism, or both.

METHODS

Clinical evaluation, hormone testing, and genetic analysis of the CYP21A2 gene were performed in 60 female patients who visited department of endocrinology of Peking Union Medical College Hospital (PUMCH) for acne, hirsutism, or both from May to November of 2018. The average age of the patients was 26.72 ± 5.73 years. ACTH, Plasma cortisol, LH, FSH, PRL, estradiol, progesterone, testosterone, 17-hydroxyprogesterone (17-OHP), and dehydroepiandrosterone sulfate (DHEA-S) were measured in all participants. Polymerase chain reaction (PCR) combined with sequencing and multiplex ligation dependent probe amplification (MLPA) technique were used to detect the mutation of the CYP21A2 gene. The prevalence of CYP21A2 mutation was compared between the patients and 60 controls, as well as the data in different genetic variant database.

RESULTS

A total of 8.3% (5/60) of individuals with acne, hirsutism, or both in this study were found to harbor heterozygotic CYP21A2 mutation, and the frequency was significantly higher than that in public databases. Identified mutations included V282L (n = 2), I173N (n = 1), E6 cluster [I237N, V238E, and M240K (n = 1)] and large deletion (n = 1). There was no significant difference in hormone levels between heterozygous carriers and subjects with normal CYP21A2 genes.

CONCLUSIONS

The prevalence of heterozygous CYP21A2 mutation detected in patients with acne, hirsutism, or both was significantly higher than in the general population. Whether the heterozygous mutation of CYP21A2 is the cause of clinical symptoms needs further assessment.

The distribution of intrafamilial CYP21A2 mutant alleles and investigation of clinical features in Turkish children and their siblings in Southeastern Anatolia

Background The genotype-phenotype relationship shows regional variability in 21-hydroxylase deficiency (21-OHD) caused by mutations in the CYP21A2 gene. This study focuses on the genotype-phenotype compatibility between patients and their siblings in a region where consanguineous marriage is common. Methods The most common mutations (I2G-P30L-I172N-V237E-M239K-V281L-Q318X-R356W-F306 + nt) were studied in 60 children with 21-OHD and 40 siblings (12 symptomatic and 28 asymptomatic; mean age 5.89 ± 4.63 and 8.34 ± 2.22 years, respectively). The allele number (patients; 93 siblings; 70 alleles) was counted for each case. Salt wasting (SW; n = 38), simple virilizing (SV; n = 11) and non-classical congenital adrenal hyperplasia (NCCAH; n = 11) types were compared with their genotypes classified into groups Null-AB-C-D-E based on enzyme impairment. Results Disease-causing mutations were identified in unrelated alleles: 80 out of 93 alleles (86%) in the patients: SW, 51/56 (91%); SV, 14/16 (87.4%) and NCCAH, 15/21 (71.4%). There were 43 out of 70 alleles (61.4%) in the siblings (asymptomatic, 25/50 [50%]; symptomatic, 18/20 [90%]). The most frequently detected mutations in the patients were: I2G (22%), Q318X-P30L-V281L (13% each). The distribution of the most common mutations by clinical types was: SW: I2G-Q318X (30.2%-19.6%), SV: I172NI2G (37.5%-18.7%), NCCAH: V281L-P30L (33.3%-28.5%). In patients and symptomatic siblings, the concordance percentages by genotype groups were: Null (100%-100%), A (85%-60%), B (100%-Not applicable), C (41.6%-50%). Eleven out of 28 asymptomatic siblings had disease-causing mutations (four, severe; one, moderate; six, mild). The distribution of genotypes by phenotypes were: SW: Null-A (88%), SV: B-A (50%-41.6%), NCCAH: C (100%). Conclusions This study showed that the most common alleles were IN2G-Q381X-R356W-P30L-V281L in the children with 21-OHD and asymptomatic siblings, and that the phenotype can be predicted from the genotype except for the P30L-V281L. This result suggests that the most common mutations in 21-OHD are similar to previous reports, but that the genotype-phenotype compatibility is good except for group C showing regional variability, and that genotyping of siblings discovered new patients.

The impact of CYP21A2 (P30L/I172N) genotype on female fertility in one family

Background

The simple virilizing (SV) form of congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder usually caused by steroid 21-hydroxylase deficiency due to I172N missense mutation at the CYP21A2 gene. Clinical presentation encompasses virilization of external genitalia in newborn females and pseudoprecocious puberty in both sexes, due to reactive androgen overproduction. The aim of this study was to present two sisters with an SV form of CAH and distinctive genotype, detected and treated since childhood with a poor compliance and poor metabolic control hindering the fertility.

Case presentation

We retrospectively reviewed the clinical, biochemical, and molecular data of two sisters with CAH a 46,XX karyotype when they reached an age of 35 and 38 years, respectively, and were attempting conception for several years. They had been diagnosed with SV form of CAH at the age of 7 and 9 years, respectively, by the standard clinical and biochemical procedures, presenting with severe virilization due to androgen excess. Follow-up was performed through standard methods of measurement of 17-OHP, testosterone, and ACTH. Clitoroplasty with vaginoplasty was performed at the age of 18 in the older sister. Using PCR/ACRS, we performed molecular analysis of the nine most common point CYP21A2 mutations in the patients and family members. The P30L/II72N genotype was observed in both sisters. They had inadequate metabolic control due to noncompliance until decision to conceive. IVF was performed three times in the older sister without success. Sufficient follicles were harvested and fertilized; however, the embryos were lost 3–5 days after implantations. The younger sister is preparing for IVF. She underwent follicle harvesting and the embryos were frozen awaiting appropriate hormonal balance for embryo transfer. The I172N mutation in the heterozygote state was observed in their other two sisters, whose fertility was unaffected.

Conclusions

Despite significant improvements over the last years in achieving fertility in female patients with SV CAH, it is highly dependent upon the severity of virilization and the metabolic control. The role of P30L mutation in infertility and unsuccessfully assisted reproduction remains to be elucidated.

[Clinical features and genetic characteristics of 33 patients with simple virilizing form of 21-hydroxylase deficiency]

Objective: To analyze the clinical features and genotypes of adult patients with simple virilizing form of 21-hydroxylase deficiency (SV 21-OHD). Methods: This is a retrospective study including 33 patients with SV 21-OHD from January 2015 to March 2018 in the Ninth People's Hospital of Shanghai Jiao Tong University School of Medicine. Results: The diagnostic age of the patients was (26.3±6.5) years old. All patients presented with signs of masculinization, such as short stature (100%), clitoromegaly/microphallus (89.65%, 26/29), undeveloped breasts (82.76%, 24/29), deep voice (55.17%,16/29) and primary amenorrhea (89.65%, 26/29). The serum levels of 17-hydroxyprogesterone (17-OHP), androstenedione (AD) and testosterone were significantly elevated in 90.9%, 93.9% and 91.2% of the patients, respectively. Thirteen types of mutations were identified in CYP21A2 from these patients. Among them, I173N accounted for 40% and I2 G accounted for 18.33%. Four patients were found with multiple mutations in CYP21A2. Conclusions: Short stature, clitoromegaly/microphallus and primary amenorrhea are the most common clinical features in adult patients with SV 21-OHD. Serum levels of 17-OHP and AD are important indices for the diagnosis and monitoring of the patients. I173N and I2 G are the two most prevalent mutations in patients of the present study. Limitation of clinical recognition and delay in treatment contribute to the short stature of the SV 21-OHD patients.

Therapeutic challenges in a patient with the simple virilizing (SV) form of congenital adrenal hyperplasia (CAH) due to the P30L/I172N genotype

Background Steroid 21-hydroxylase deficiency is an autosomal recessive disorder, present in 90-95% of all cases with congenital adrenal hyperplasia (CAH). The classical simple virilizing (SV) form of the disease causes virilization of the external genitalia in newborn females and pseudo-precocious puberty in both sexes, due to reactive androgen overproduction. Case presentation We describe a 3.5-year-old girl presenting with pubarche, P2 according to Tanner, advanced bone age of 6 years and 10 months, and high serum levels of 17-hydroxyprogesterone (17-OHP). Molecular analysis of the nine most common pseudogene-derived CYP21A2 point mutations was performed in the patient and her family members using the polymerase chain reaction/amplification-created restriction site (PCR/ACRS) method. We detected the P30L/I172N genotype in the patient. She had inherited a mild P30L mutation from her mother and a severe I172N mutation from her father. Conclusions Although the CAH phenotype is determined by the allele that produces most of the enzyme activity and the mild non-classical (NC) phenotype should be expected, the mild P30L known to be more virilizing probably induced the classical SV phenotype in our patient. A continuous regimen of hydrocortisone at a recommended dose failed to decrease the 17-OHP sufficiently. Careful tapering of the dose did not help, and her pubic hair advanced to P3 according to Tanner. Individually tailored treatment is warranted in this patient.

[Molecular and clinical study on homozygous or heterozygous large deletion of CYP21A2 gene in 21-OHD patients]

Objective: To explore the relationship between homozygous or heterozygous large deletion of CYP21A2 gene and clinical manifestation in 21-hydroxylase deficiency (21-OHD) patients. Methods: The records of 100 patients with 21-OHD were collected between June 2016 and December 2017 in Peking Union Medical College Hospital. Large deletion of CYP21A2 gene was detected by multiplex ligation probe amplification (MLPA). The biochemical results and clinical symptoms of patients with homozygous or heterozygous large deletion were analyzed in order to investigate the influence of complete or single allele deletion of CYP21A2 gene on 21-OHD patients. Results: Large deletion of CYP21A2 gene was detected in 33 patients by MLPA, including 13 males and 20 females, with an median age of 10 (6,16) years. Two of them had simultaneous deletions of two alleles. Among 31 patients with heterozygous deletion, 16 were combined with gene mutations that severely affected 21-hydroxylase enzyme activity (I2G and Q318X), 15 with mutations that retained part enzyme activity (I172N and P30L). Two patients with complete deletion of CYP21A2 gene had no significant difference in biochemical and clinical manifestations compared with those with single allele deletion combined with another gene mutation that severely affected enzyme activity. Both kinds of patients above were manifested as severe salt-wasting type. Patients with a single allele deletion and a mutation retaining part enzyme activity were manifested as mild simple-viralizing type. Conclusion: Large deletion of CYP21A2 gene could appear in 21-OHD patients and the phenotype is similar to that of salt-wasting patients with heterozygous large deletion.

[Diagnostic value of multiplex ligation dependent probe amplification combined with Sanger sequencing in 21-hydroxylase deficiency]

Objective: To study the procedure of CYP21A2 gene mutation detection in 21-hydroxylase deficiency (21-OHD) patients. Methods: The detail clinical and biochemical data of 51 patients with 21-OHD [18 males and 33 females, with an average age of (16.4±9.9) years] were collected between December 2016 and December 2017 at Department of Endocrinology, Peking Union Medical College Hospital. Multiplex ligation dependent probe amplification (MLPA) and Sanger sequencing of the CYP21A2 gene were used to clarify the cause of 21-OHD. The genotype-phenotype correlation was also analyzed. Results: The incidences of large deletion, 8 bp deletion, I2G, I172N and F306+T were 19.6% (20/102), 1.0% (1/102), 30.4% (31/102), 25.5% (26/102) and 1.0%(1/102), respectively, and the detection rate of gene mutation in 51 21-OHD patients was 77.5% (79/102) by MLPA test. Except large and 8 bp deletion, all above mutations contained in MLPA and other 8 mutations, including P31L, Q319X, R361L, R357W, V282L, R484Q, G425S and R342W were detected, and the detection rate was 79.4% (81/102) by Sanger sequencing of CYP21A2. MLPA combined with direct sequencing identified mutations in all patients. Genotype correlated well with clinical phenotype in 21-OHD patients. Conclusions: When MLPA or CYP21A2 gene sequencing were used alone to diagnose the cause of 21-OHD, gene mutations in all patients could not be detected. The combination of the two methods can complement each other and fully clarify the underlying causes of 21-OHD.

Functional characterization and molecular modeling of the mutations in CYP21A2 gene from patients with Congenital Adrenal Hyperplasia

Steroid 21-Hydroxylase deficiency is an inherited autosomal recessive metabolic disorder of the adrenal steroidogenesis caused due to mutations in the CYP21A2 gene in 95% of CAH cases. Notably, the de novo mutations arise at the rate of 3-5%, therefore the functional characterization is of utmost importance for categorization of the novel mutations. Herein, we have functionally characterized the CYP21A2 missense mutations viz., p. F306V and p. H365N. Notably, both the mutations were harbored by the patients exhibiting the non classical phenotype. We followed the approach of in vitro characterization of the mutant proteins expressed in COS7 cells. Of note, all the mutant constructs exhibited reduced residual enzyme activity fraternized with altered kinetic constants accompanied by higher requirement for the activation energy. Further, there was reduced protein expression in the mutant constructs to that of the wild-type. Molecular modeling suggested alteration in the structure-function relationship of the protein due to mutations. The evidence suggested by the in vitro and the in silico characterization of mutations directed us to conclude that both, p. F306V and p. H365N should be considered as non classical CAH causing mutations. Conceivably, the knowledge about the functional consequences of the mutations is the basis for improved genetic counseling with respect to prognosis and therapeutic implications.

Testicular adrenal rest tumors in boys with 21-hydroxylase deficiency, timely diagnosis and follow-up

BACKGROUND

Testicular adrenal rest tumors (TARTs) are found in 30-94% of adult males with congenital adrenal hyperplasia (CAH). We sought to explore TART appearance through yearly ultrasound examination of testes in young boys with CAH, and its association with metabolic control and genetic mutations.

METHODS

Twenty-five boys with 21-hydroxylase deficiency in the age group 4-18 years diagnosed during the period 2001-2016 were included in the study. ACTH, 17-hydroxyprogesterone, androstenedione and testosterone were measured at 4-month intervals. Growth and BMI were assessed at the time of evaluation. PCR/ACRS method was used for CYP21A2 gene analysis. Testicular ultrasound examination was performed yearly.

RESULTS

TARTs were detected by ultrasound in 8 children at the age of 6-16 years (13.2 years average). Five had salt-wasting form, two had simple virilizing form and one had non-classic form of CAH. Significant differences in the17OHP and androstenedione levels were detected between the boys, adherent and non-adherent to therapy. Inadequate metabolic control was not different in boys with and without TART (11/17 and 5/8 respectively). No significant difference was detected in the distribution of genetic mutations or adherence to therapy between patients with and without TARTs. One patient had a mutation not reported thus far in TART and another developed leukemia.

CONCLUSION

TART is not rare in young boys with CAH, irrespective of the specific mutation or metabolic control. Ultrasound screening helps timely diagnosis and adjustment of therapy.

Data on the 21-Hydroxylase deficient CAH patients and the identification of known/novel mutations in CYP21A2 gene

This article presents the dataset regarding spectrum of mutations in 21-Hydroxylase deficient CAH patients as described in “The spectrum of CYP21A2 mutations in Congenital Adrenal Hyperplasia in an Indian cohort” (R. Khajuria, R. Walia, A. Bhansali, R. Prasad, 2017) [1]. This dataset features about the CAH patients in the cohort, their classification into subtypes and finally screening the exon–intron boundaries of 21-Hydroxylase gene (CYP21A2) to detect common mutations, novel mutations along polymorphisms in the CYP21A2 gene. The specified large set of primers and the parameters for the mutation detection allow the identification and molecular characterization of CYP21A2 gene in the CAH patients.

Molecular genetic analysis in 93 patients and 193 family members with classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Croatia

Congenital adrenal hyperplasia owing to 21-hydroxylase deficiency is caused by mutation in the CYP21A2 gene. The frequency and spectrum of CYP21A2 mutations and genotype-phenotype correlations among different populations are variable. Aim of this study was to define mutation frequency and spectrum of CYP21A2 gene mutations in patients with classical 21-hydroxylase deficiency (21OHD) and their family members in Croatia and study genotype-phenotype correlation. Clinical features and mutations of CYP21A2 gene in 93 unrelated 21OHD patients and 193 family members were examined. In this cohort, 66 patients were affected with salt wasting (SW) form, and 27 were affected with simple virilizing (SV) form of the disease. Mutations were identified in both alleles (67% compound heterozygous and 33% homozygous) in 91 of 93 patients. Deletions and conversions were found in 18.8% and point mutations in 79.6% alleles. Mutations in 3 alleles (1.6%) remained unidentified (in one patient we found only one, while in other no mutations were found at all). The most common point mutations were Intron 2 splice mutation IVS2-13 A/C>G (35.5%) and p.R357W (16.7%). Genotypes were categorized into Groups 0, A, B and C according to the extent of enzyme impairment. Genotype-phenotype concordance was 100%, 85% and 75% for Groups 0, A and B, respectively. Since only classical 21OHD patients were studied, Group C comprised solely p.P31L mutation and had 73% patients with SV and 27% with SW phenotype. Intrafamilial phenotypic variability was found in two families. CYP21A2 genetic analysis in 193 family members showed that 126 parents were heterozygous carriers, 3 were newly discovered patients, 2 fathers were not biological parents, and mutations were not detected in 3. Among 59 siblings, 32 were heterozygous carriers, 15 carried normal alleles, and 12 were patients (4 newly diagnosed). Genotype-phenotype divergence observed in this study suggests caution in preconceptional counseling and prenatal diagnosis of CAH. High frequency of p.R357W mutation was found in Croatian patients with classical 21-OHD. Genotyping of family members discovered new patients and thus avoided pitfalls in genetic counseling when the parents were found to be affected.

The spectrum of CYP21A2 mutations in Congenital Adrenal Hyperplasia in an Indian cohort

Congenital Adrenal Hyperplasia (CAH) is a common autosomal recessive disorder of the adrenal steroidogenic pathway. The most common form of CAH is due to mutations in CYP21A2 gene. The incidence of mutations in the CYP21A2 gene and the genotype-phenotype correlations vary among different populations. Therefore, the aim of the study was to establish the spectrum of mutations and to evaluate genotype-phenotype correlation in Indian CAH population. Molecular defects were investigated in 110 alleles (55 patients) in the present study. Notably, we identified disease causing mutations in 106 of 110 (96.4%) alleles whereas the frequency of undetectable mutations was 3.6%. The i2g mutation (20%) was found to be the most common in CAH patients. The second most common mutation was p.R356W (14.5%). p.I172N and 8-bp deletion in exon 3 accounted for 12.7% of the mutated alleles. In descending order, the other mutations present were p.Q318X (9%), E6 Cluster (5.4%), p.V281L (3.6%) and large gene deletion (3.6%). Additionally, p.P267L and frameshift mutation (L307fs/F306+T) were also detected in the Indian cohort with frequency of 1.8% and 5.4% respectively.rare mutation/rare mutations in the CYP21A2 gene were detected viz., p.D234D (NCBI accession number - KF812549), p.F306V (NCBI accession number - KF534754), p.P357P (NCBI accession number - KF692099) and p.H365N (NCBI accession number - KF447378). The genotypes of the patients were categorized into four groups null, A, B and C. Of note, correlation between genotype and phenotype is sufficiently strong, to be of clinical significance in the genetic counseling.

Detection of mutations in the CYP21A2 gene: genotype-phenotype correlation in Slovenian couples with conceiving problems

The objective of this study was to compare the CYP 21A2 genetic profiles of couples with unexplained fertility problems (UFP) with genetic profiles of healthy controls (HCs). Furthermore, we analyzed associations between mutations in the CYP21A2 gene and various clinical and laboratory parameters. Allele-specific polymerase chain reaction (PCR) was used in 638 probands with UFP and 200 HCs. Statistic analysis with χ² was used to study the association of mutations with infertility. The effect of mutations on particular clinical and laboratory parameters was assessed with the analysis of variance (ANOVA) test. With regard to the CYP21A2 gene, 0.6% of probands with UFP and 0.5% of HCs were positive for the c.290-13A/C>G mutation; 0.6% of probands with UFP and 1.5% of HCs were positive for the p.I172N mutation; there were no probands with UFP positive for the p.P30L mutation, whereas 0.5% of HCs were; and 0.2% of probands with UFP and 0.5% of HCs were found to have the p.V281L mutation. We found a significant association between c.290-13A/C>G mutation and the frequency of significant hormone deviations (χ² = 6.997, p = 0.008). Similar association was also observed between the c.29013A/C>G mutation and the frequency of polycystic ovary syndrome (PCOS) (χ² = 16.775, p = 0.000). Our findings indicate that no significant difference in the prevalence of CYP 21A2 mutations can be found in probands with UFP when compared with HCs without infertility history. The results also imply the significant association of the c.290-13A/ C>G mutation in the CYP21A2 gene, not only with the frequency of PCOS, but also with the frequency of significant hormone deviations.

Mutation detection of CYP21A2 gene in nonclassical congenital adrenal hyperplasia patients with premature pubarche

Background:

Congenital adrenal hyperplasia (CAH) due to mutations in the gene encoding 21-hydroxilase is one of common disease with an autosomal recessive form. In this study, our aim is to detect the prevalence of eight common mutations in nonclassical congenital adrenal hyperplasia (NCAH).

Materials and Methods:

A total of 30 patients with clinical and laboratory evidence of NCAH was selected. Gene-specific polymerase chain reaction (PCR) without contamination of pseudogene was carried out, and PCR product of this step was used to amplification-refractory mutation system PCR on eight common mutations in CYP21A2 gene.

Results:

Two heterozygote patients for I2G mutation and six heterozygote patients for Q318X mutation is reported in our study. These mutations associated with the classic form of CAH, and heterozygotes presented with NC symptom, including premature pubarche and hirsutism.

Conclusion:

There are some data about the association of the mutation with the clinical form of CAH including classic (salt-wasting and simple virilizing) and NC form. I2G and Q318X mutations were reported in classic form in homozygote state, but the heterozygote form associated with NC form. CAH diagnosis with NC symptom and with measurement of 17-hydroxyprogestrone as NCAH is not a trusted assessment and require to molecular analysis for accurate diagnosis.

21-hydroxylase deficiency-induced congenital adrenal hyperplasia in 230 Chinese patients: Genotype-phenotype correlation and identification of nine novel mutations

Steroid 21-hydroxylase deficiency (21-OHD) caused by the CYP21A2 gene mutations accounts for more than 90% of congenital adrenal hyperplasia (CAH) cases. In this study, molecular defects of 230 patients with 21-OHD were investigated. Point mutations of CYP21A2 gene were analyzed by Sanger sequencing, and large gene deletions were detected by multiplex ligation-dependent probe amplification (MLPA). Nine micro-conversions and 18 spontaneous mutations accounted for 74.6% of alleles, while large gene deletions and large gene conversions accounted for 25.4% of alleles. The most frequent micro-conversion was c.292-13A/C>G (I2G) (35%), followed by p.I173N (14.3%), p.R357W (5.9%) and p.Q319* (4.6%). Nine novel mutations were identified in these patients, which were predicted to hamper the 21-hydroxylase protein function in varying degrees. Genotype and phenotype correlated well in 89.6% of our patients, but disparity in phenotypic appearance also appeared in a small portion of the patients. 16.1% of the patients carried homozygous genotypes while 83.9% of patients carried compound heterozygous mutations. We concluded that the frequency of CYP21A2 mutations in our study was slightly different from those reported for other ethnic groups. Micro-conversions were the main category of the mutation spectrum, while large deletions and large gene conversions could also cause 21-OHD. A large portion of different types of the compound heterozygous genotypes may partially contribute to the discordance in genotype-phenotype comparison. This study expanded the CYP21A2 mutation spectrum of Chinese patients and could be helpful in prenatal diagnosis and genetic counseling for 21-OHD patients.

Congenital Adrenal Hyperplasia with Non-functional Mutations in Both Alleles in a Clinically Unaffected Infant

BACKGROUND

Results in neonatal screening programs aiming at detection of congenital adrenal hyperplasia (CAH) can only report elevated levels of 17-hydroxy-progesterone (17-OHP), without being able to differentiate presence or absence of salt loss.

AIM

To predict presence or absence of salt loss in newborn infants with CAH.

METHODS

The first specimen of suspected CAH in samples sent from People's Democratic Republic of Laos (Lao PDR) was investigated for known mutations in CAH associated with salt loss.

RESULTS

Molecular genetic diagnosis revealed mutations associated with loss of function in both alleles; however, the infant was clinically unaffected even without any corticosteroid substitution therapy.

CONCLUSIONS

Although molecular genetic methods can theoretically predict loss of function in CAH, our infant was clinically unaffected even without therapy at 6 years of age. We speculate that in CAH, remaining enzyme activity can be sufficiently high, despite the presence of loss of function mutations, which do not affect infants clinically.

A de novo mutation in CYP21A2 gene in a case of in vitro fertilization

Congenital adrenal hyperplasia, one of the most frequent autosome recessive disorders, is caused by defects in steroidogenic enzymes involved in the cortisol biosynthesis. Approximately 95% of the cases are caused by abnormal function of the 21-hydroxylase enzyme. This deficiency leads to androgen excess, consequently, to virilization and rapid somatic growth with accelerated skeletal maturation. Mutations in CYP21A2 are responsible for different forms of 21-hydroxylase deficiency. Mild impairment in the enzymatic activity causes the non-classic or late-onset congenital adrenal hyperplasia that is observed with a prevalence of 1 in 1000 subjects in different populations. The present paper describes a de novo mutation that occurred in the paternal meiosis. The child, who was conceived by in vitro fertilization, presented with precocious puberty and diagnosed with non-classical 21-hydroxylase deficiency. DNA sequencing showed the compound heterozygosis for a de novo CYP21A1P/A2 chimeric gene and the p.Val281Leu mutation inherited from her mother, who was heterozygous for the mutation. The chimeric gene showed pseudogene-derived sequence from 5′-end to intron 3 and CYP21A2 sequences from intron 3 to 3′-end of the gene. Sequencing analysis of the father did not show any mutation. The multiplex ligation-dependent probe amplification (MLPA) assay did not indicate loss of DNA discarding gene deletion but confirmed the chimeric gene. In addition, supernumerary copies of CYP21A1P were observed for both parents and for the affect child. Since paternity has been confirmed, those results suggest that a de novo large gene conversion in the paternal meiosis could have occurred by misalignment of alleles bearing different copy numbers of genes in CYP21 locus.

Direct Molecular Diagnosis of CYP21A2 Point Mutations in Macedonian and Serbian Patients with 21-Hydroxylase Deficiency

Background

Steroid 21-hydroxylase deficiency is present in 90–95% of all cases with congenital adrenal hyperplasia (CAH), an autosomal recessive disorder. It can present as the severe classical salt wasting (SW) or simple virilising (SV) form, or the milder, nonclassical form. Nine pseudogene-derived point mutations account for about 80% of all defects in the CYP21A2 gene coding the 21-hydroxylase enzyme.

Methods

We have studied nine CYP21A2 point mutations in 61 Macedonian and 24 Serbian patients with different clinical presentations of CAH, using the PCR/ACRS method.

Results

Six different mutations were detected in 71.3% of alleles of the Macedonian patients. The most prevalent mutation was IVS2. Mutations were detected in 85.4% of the SW, 83.4% SV and 47.7% LO alleles. In the Macedonian patients the most common genotype was IVS2/IVS2. Five different mutations were detected in 64.6% of alleles of the Serbian patients. The most prevalent was P30L. Mutations were present in 83.3% SW, 80% SV and 50% of the LO alleles. In the Serbian patients, the P30L/P30L genotype was the most frequent.

Conclusions

Specific CYP21A2 mutations are involved in different clinical forms of CAH. High frequency of P30L was found in both populations. Also, high prevalence of the mild P30L mutation was found in both the Macedonian and Serbian classical SV patients. Our findings support the role of the P30L mutation in pronounced virilisation. An unusual finding is the low frequency of V281L in the Macedonian non-classical patients and its absence in the ones from Serbia.

High carrier frequency of 21-hydroxylase deficiency in Cyprus

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder caused by mutations in the CYP21A2 gene. The carrier frequency of CYP21A2 mutations has been estimated to be 1:25 to 1:10 on the basis of newborn screening. The main objective of this study was to determine the carrier frequency in the Cypriot population of mutations in the CYP21A2 gene. Three hundred unrelated subjects (150 males and 150 females) from the general population of Cyprus were screened for mutations in the CYP21A2 gene and its promoter. The CYP21A2 genotype analysis identified six different mutants and revealed a carrier frequency of 9.83% with the mild p.Val281Leu being the most frequent (4.3%), followed by p.Qln318stop (2.5%), p.Pro453Ser (1.33%), p.Val304Met (0.83%), p.Pro482Ser (0.67%) and p.Met283Val (0.17%). The notable high CYP21A2 carrier frequency of the Cypriot population is one of the highest reported so far by genotype analysis. Knowledge of the mutational spectrum of CYP21A2 will enable to optimize mutation detection strategy for genetic diagnosis of 21-OHD not only in Cyprus, but also the greater Mediterranean region.

Molecular genetic analysis of CYP21A2 gene in patients with congenital adrenal hyperplasia

CONTEXT

Congenital adrenal hyperplasia (CAH) is one of the inborn errors of metabolic disorder inherited in an autosomal recessive manner caused by the defects in the steroid 21 hydroxylase CYP21A2 gene. We analyzed the genotype of 62 patients with classic CAH.

AIMS

To find out the underlying mutations of CYP21A2 gene.

SETTINGS AND DESIGN

Cohort of CAH patients.

MATERIALS AND METHODS

Sixty-two patients with CAH were recruited from the endocrine clinic at AIIMS. Electrochemiluminiscence method was used for estimating the levels of cortisol. Radioimmunoassay kit-based method was used for estimating the 17 OHP levels. Polymerase chain reaction amplification was done using specific primers to amply the CYP21A2 gene.

STATISTICAL ANALYSIS USED

Statistical analysis was done by using Epi Info Version 3.5.1.2008.

RESULTS

Out of 62 patients, 50 were simple virilizers (SV) and 12 were salt wasters (SW). Fifty-six were females and six were males. Five 46, XX children were reared as males. Age at presentation varied from 8 months to 38 years. Molecular genetic analysis revealed that the highest number of patients harboured (In 2) IVS2-13 A/C > G (48%), followed by p.P30L (46%), p.Q318X (35%), (D 8 bp) deletion 8 bp (26%), p.I172N (26%), and p. R356W (20%) mutations.

CONCLUSION

This is among the few studies to analyze the mutational spectrum of CYP21A2 gene in a large CAH cohort from India. Molecular diagnosis of CYP21A2 gene should be considered as part of the CAH evaluation to assess the risk of the patients/parents/siblings and to offer genetic counseling.