CYP21 analysis and phenotype/genotype relationship in the screened population of the Italian Emilia-Romagna region

Genetic Characterization of a Cohort of Italian Patients with Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency

INTRODUCTION

Defects in the steroid 21-hydroxylase gene (CYP21A2) cause 21-hydroxylase deficiency (21OHD), the main cause of congenital adrenal hyperplasia (CAH). The disease shows a broad spectrum of clinical forms, ranging from severe or classical (salt wasting, SW, and simple virilizing, SV), to mild late onset or nonclassical (NC). 21OHD affects 1 in 15,000 in its severe classic form and 1 in 200-1000 in its mild NC form. There are many studies reporting the frequency of CYP21A2 pathogenic variants in different populations; however, few of them provide comprehensive information about Italian patients. Here, we present genetic results from a cohort of 245 unrelated Italian individuals with clinical diagnosis of CAH due to 21OHD.

METHODS

A specific polymerase chain reaction (PCR) protocol combined with Sanger sequencing was used for CYP21A2 analysis. The multiplex ligation-dependent probe amplification (MLPA) assay was employed for copy number variation (CNV) determination.

RESULTS

One hundred fourteen (46.5%) of the index cases had the NC form, 57 (23.3%) had the SV form, and 74 (30.2%) presented the SW form of the disease. The most prevalent variant found in NC patients was the p.Val282Leu (51.3%), while the most frequent variants in the classical form were p.Ile173Asn (8.6%) and c.293-13C>G (26.0%). In our study, the frequency of large rearrangements was 15.3%, with CAH-X alleles representing 40% of all DEL/CONV. In addition, 12 alleles carried rare variants, and 1 had a novel variant p.(Arg342Gln). We observed phenotype-genotype correlation in 94.7% of cases. A complete concordance was observed in Groups 0 (enzyme activity completely impaired) where all patients had the SW form as expected. In Group A (0-1% residual enzyme activity), 78.4% of patients had the anticipated SW form while 21.6% were diagnosed with the SV form. Within Group B (~ 2% residual enzyme activity), 93.4% of patients exhibited SV form and 6.5% SW disease. Finally, 92.6% and 7.4% of patients belonging to Group C (enzyme partially impaired to ~ 20-60% residual activity) exhibited NC and SV phenotypes, respectively.

CONCLUSION

This work, representing a comprehensive genetic study, expanded the CYP21A2 variants spectrum of Italian patients with 21OHD and could be helpful in prenatal diagnosis and genetic counseling.

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.

Growth Trajectory and Adult Height in Children with Nonclassical Congenital Adrenal Hyperplasia

BACKGROUND

Children with nonclassical congenital adrenal hyperplasia (NCCAH) often present increased growth velocity secondary to elevation of adrenal androgens that accelerates bone maturation and might compromise adult height (AH).

OBJECTIVE

The aim of the study was to analyze prognostic factors affecting growth trajectory (GT) and AH in children with NCCAH.

METHODS

The study was a retrospective, multicentric study. The study population consisted of 192 children with a confirmed molecular diagnosis of NCCAH, followed by pediatric endocrinology centers from diagnosis up to AH. Clinical records were collected and analyzed. AH (standard deviation score; SDS), pubertal growth (PG) (cm), GT from diagnosis to AH (SDS), and AH adjusted to target height (TH) (AH-TH SDS) were evaluated as outcome indicators using stepwise linear regression models.

RESULTS

The stepwise linear regression analysis showed that AH and AH-TH were significantly related to chronological age (CA) (p = 0.008 and 0.016), bone age (BA)/CA ratio (p = 0.004 and 0.001), height (H) (p < 0.001 for both parameters) at NCCAH diagnosis, and TH (p = 0.013 and <0.001). PG was higher in males than in females (22.59 ± 5.74 vs. 20.72 ± 17.4 cm, p = 0.002), as physiologically observed, and was positively related to height (p = 0.027), negatively to BMI (p = 0.001) and BA/CA ratio (p = 0.001) at NCCAH diagnosis. Gender, genotype, biochemical data, and hydrocortisone treatment did not significantly impair height outcomes of these NCCAH children.

CONCLUSIONS

The results of this study suggest that AH and GT of NCCAH patients are mainly affected by the severity of phenotype (CA, BA/CA ratio, and H) at the time of diagnosis.

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.

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.

Characteristics of In2G Variant in Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency

Substantial research has been performed during the last decades on the clinical and genetic variability of congenital adrenal hyperplasia (CAH) and its most common form, 21-hydroxylase deficiency (21OHD). CAH is one of the most prevalent autosomal recessive diseases in humans, and it can be divided into classic-further subdivided into salt wasting (SW) and simple virilizing (SV)-and non-classic (NC) forms. Pathogenic variants of CYP21A2 gene, encoding the 21-hydroxylase enzyme, have been reported with variable prevalence in different populations. NM_000500.9:c.293-13C/A>G (In2G) variant represents the most common CYP21A2 gene changes related to the classic 21OHD form. However, the phenotype of In2G carriers is variable depending on the variant homozygous/heterozygous status and combination with other CYP21A2 pathogenic variants. In addition, identical genotypes, harboring the homozygous In2G variant, can present with variable phenotypes including the SW and SV or rarely NC form of the disease. Here, we analyze and present the clinical aspects, genotype/phenotype correlations, and other characteristics related to the CYP21A2 In2G variant.

Assessment of the most common CYP21A2 point mutations in a cohort of congenital adrenal hyperplasia patients from Egypt

Objectives Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder caused by defects in the CYP21A2 gene. We aimed to determine the prevalence of the most commonly reported mutations among 21-OHD Egyptian patients and correlate genotype with phenotype. Methods Molecular analysis of the CYP21A2 gene was performed for the detection of the six most common point mutations (p.P30L, p.I172N, p.V281L, p.Q318X, the splice site mutation Int2 [IVS2-13A/C>G], and the cluster of three mutations [p.I236N, p.V237E, and p.M239K] designed as CL6). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was performed on 47 unrelated Egyptian 21α-OH deficiency patients and their available parents to detect the presence of the six most common point mutations. Results Screening for the six most common point mutations in CYP21A2 gene, revealed mutations in 87.2% (82/94) of the studied alleles corresponding to 47 Egyptian patients. The most common mutation among the studied cases was IVS2-13C/A>G that was found to be presented in a frequency of 46.8% (44/94). The genotype/phenotype correlations related to null, A, and B groups were with PPV of 100, 55.5, and 83.3%, respectively. Conclusions The described method diagnosed CAH in 80.8% of the studied patients. Good correlation between genotype and phenotype in salt wasting and simple virilizing forms is determined, whereas little concordance is seen in nonclassical one. Furthermore, studying the carrier frequency of 21-OHD among the normal population is of great importance.

CYP21A2 Gene Pathogenic Variants: A Multicenter Study on Genotype-Phenotype Correlation from a Portuguese Pediatric Cohort

BACKGROUND

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder characterized by 3 overlapping phenotypes: salt-wasting (SW), simple virilizing (SV), and non-classic (NC). We aimed at conducting a nationwide genotype description of the CAH pediatric patients and to establish their genotype-phenotype correlation.

METHODS

CAH patients were recruited from Portuguese pediatric endocrinology centers and classified as SW, SV, or NC. Genetic analysis was performed by polymerase chain reaction (sequence specific primer, restriction fragment length polymorphism) or direct Sanger sequencing. Genotypes were categorized into 4 groups (0, A, B, and C), according to their predicted enzymatic activity. In each group, the expected phenotype was compared to the observed phenotype to assess the genotype-phenotype correlation.

RESULTS

Our cohort comprises 212 unrelated pediatric CAH patients (29% SW, 11% SV, 60% NC). The most common pathogenic variant was p.(Val282Leu; 41.3% of the 424 alleles analyzed). The p.(Val282Leu) variant, together with c.293-13A/C>G, p.(Ile173Asn), p.(Leu308Thr), p.(Gln319*), and large deletions/conversions were responsible for 86.4% of the mutated alleles. Patients' stratification by disease subtype revealed that the most frequent pathogenic variants were c.293-13A/C>G in SW (31.1%), p.(Ile173Asn) in SV (46.9%), and p.(Val282Leu) in NC (69.5%). The most common genotype was homozygosity for p.(Val282Leu; 33.0%). Moreover, we found 2 novel variants: p.(Ile161Thr) and p.(Trp202Arg), in exons 4 and 5, respectively. The global genotype-phenotype correlation was 92.4%. Group B (associated with the SV form) showed the lowest genotype-phenotype correlation (80%).

CONCLUSION

Our cohort has one of the largest NC CAH pediatric populations described. We emphasize the high frequency of the p.(Val282Leu) variant and the very high genotype-phenotype correlation observed.

Analysis of phenotypes and genotypes in 84 patients with 21-Hydroxylase deficiency in southern China

OBJECTIVE

21-hydroxylase deficiency (21-OHD) caused by mutation in CYP21A2 gene is the most common form of Congenital adrenal hyperplasia (CAH). This study aimed to analyze the gene mutation frequency and the phenotype-genotype correlation of 21-OHD patients from southern China.

METHOD

The clinical features, laboratory tests and gene mutational analysis of 84 patients with 21-OHD were retrospectively investigated. Subsequently, the correlation between phenotypes and genotypes of these patients was analyzed.

RESULTS

59 of 84 cases of 21-OHD (70.2%) were classified as salt-wasting (SW) forms presenting adrenal crisis or other signs of salt loss at the age between neonatal period and 2 months, and other 25 cases were classified as simple virilizing (SV) forms. Mutations of CYP21A2 gene on both alleles were found in all 84 patients (168 alleles). The most common types of mutations included micro-conversions (129/168, 76.8%), large gene conversions and deletions (23/168, 13.7%), and bona fide point mutations (16/168, 9.5%). In increasing order of frequency, the most common micro-conversions were I2G (41.1%), p.I172N (13.1%), p.R356W (7.7%), p.Q318* (7.7%) and E6 Cluster (3.0%). Genotypes and phenotypes correlated in 86.1% of the patients analyzed.

CONCLUSION

Micro-conversions were the most common types of CYP21A2 gene mutations in our study, and the frequency of the identified mutations was not significantly different compared with most other Chinese areas and different ethnic regions. However, fewer large gene conversions and deletions were found compared to studies in other ethnic populations. Genotype-phenotype correlation was found in patients with the SW and SV forms of 21-OHD. This study expanded the number of mutations affecting CYP21A2 gene in Chinese patients with 21-OHD, providing additional information for a precise clinical diagnosis and genetic counseling.

46,XX DSD due to Androgen Excess in Monogenic Disorders of Steroidogenesis: Genetic, Biochemical, and Clinical Features

The term 'differences of sex development' (DSD) refers to a group of congenital conditions that are associated with atypical development of chromosomal, gonadal, or anatomical sex. Disorders of steroidogenesis comprise autosomal recessive conditions that affect adrenal and gonadal enzymes and are responsible for some conditions of 46,XX DSD where hyperandrogenism interferes with chromosomal and gonadal sex development. Congenital adrenal hyperplasias (CAHs) are disorders of steroidogenesis that mainly involve the adrenals (21-hydroxylase and 11-hydroxylase deficiencies) and sometimes the gonads (3-beta-hydroxysteroidodehydrogenase and P450-oxidoreductase); in contrast, aromatase deficiency mainly involves the steroidogenetic activity of the gonads. This review describes the main genetic, biochemical, and clinical features that apply to the abovementioned conditions. The activities of the steroidogenetic enzymes are modulated by post-translational modifications and cofactors, particularly electron-donating redox partners. The incidences of the rare forms of CAH vary with ethnicity and geography. The elucidation of the precise roles of these enzymes and cofactors has been significantly facilitated by the identification of the genetic bases of rare disorders of steroidogenesis. Understanding steroidogenesis is important to our comprehension of differences in sexual development and other processes that are related to human reproduction and fertility, particularly those that involve androgen excess as consequence of their impairment.

Interpretation of Genomic Sequencing Results in Healthy and Ill Newborns: Results from the BabySeq Project

Genomic sequencing provides many opportunities in newborn clinical care, but the challenges of interpreting and reporting newborn genomic sequencing (nGS) results need to be addressed for its broader and effective application. The BabySeq Project is a pilot randomized clinical trial that explores the medical, behavioral, and economic impacts of nGS in well newborns and those admitted to a neonatal intensive care unit (NICU). Here we present childhood-onset and actionable adult-onset disease risk, carrier status, and pharmacogenomics findings from nGS of 159 newborns in the BabySeq Project. nGS revealed a risk of childhood-onset disease in 15/159 (9.4%) newborns; none of the disease risks were anticipated based on the infants' known clinical or family histories. nGS also revealed actionable adult-onset disease risk in 3/85 (3.5%) newborns whose parents consented to receive this information. Carrier status for recessive diseases and pharmacogenomics variants were reported in 88% and 5% of newborns, respectively. Additional indication-based analyses were performed in 29/32 (91%) NICU newborns and 6/127 (5%) healthy newborns who later had presentations that prompted a diagnostic analysis. No variants that sufficiently explained the reason for the indications were identified; however, suspicious but uncertain results were reported in five newborns. Testing parental samples contributed to the interpretation and reporting of results in 13/159 (8%) newborns. Our results suggest that nGS can effectively detect risk and carrier status for a wide range of disorders that are not detectable by current newborn screening assays or predicted based on the infant's known clinical or family history, and the interpretation of results can substantially benefit from parental testing.

Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline

Objective

To update the congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency clinical practice guideline published by the Endocrine Society in 2010.

Conclusions

The writing committee presents updated best practice guidelines for the clinical management of congenital adrenal hyperplasia based on published evidence and expert opinion with added considerations for patient safety, quality of life, cost, and utilization.

CYP21A2 mutation update: Comprehensive analysis of databases and published genetic variants

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders of adrenal steroidogenesis. Disorders in steroid 21-hydroxylation account for over 95% of patients with CAH. Clinically, the 21-hydroxylase deficiency has been classified in a broad spectrum of clinical forms, ranging from severe or classical, to mild late onset or non-classical. Known allelic variants in the disease causing CYP21A2 gene are spread among different sources. Until recently, most variants reported have been identified in the clinical setting, which presumably bias described variants to pathogenic ones, as those found in the CYPAlleles database. Nevertheless, a large number of variants are being described in massive genome projects, many of which are found in dbSNP, but lack functional implications and/or their phenotypic effect. In this work, we gathered a total of 1,340 GVs in the CYP21A2 gene, from which 899 variants were unique and 230 have an effect on human health, and compiled all this information in an integrated database. We also connected CYP21A2 sequence information to phenotypic effects for all available mutations, including double mutants in cis. Data compiled in the present work could help physicians in the genetic counseling of families affected with 21-hydroxylase deficiency.

A genetic epidemiology study of congenital adrenal hyperplasia in Italy

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency (21OHD-CAH) is an autosomal recessive disorder affecting steroidogenesis, due to mutations in CYP21A2 (6p21.3). 21OHD-CAH neonatal screening is based on 17-hydroxyprogesterone (17OHP) serum levels, showing high type I error rate and low sensitivity to mild CAH forms. Here, we used an epidemiological approach, which estimates the allelic frequency (q) of an autosomal recessive disorder using the proportion of homozygous patients, the mutational spectrum and the inbreeding coefficient in a sample of affected individuals. We applied this approach to 2 independent Italian cohorts of patients with both clinical and molecular diagnosis of 21OHD-CAH from mainland Italy (N = 240) and Sardinia (N = 53). We inferred q estimates of 2.87% and 1.83%, corresponding to a prevalence of 1/1214 and 1/2986, respectively. CYP21A2 mutational spectra were quite discrepant between the 2 cohorts, with V281L representing 74% of all the mutations detected in Sardinia vs 37% in mainland Italy. These findings provide an updated fine-grained picture of 21OHD-CAH genetic epidemiology in Italy and suggest the need for a screening approach suitable to the detection of the largest number of clinically significant forms of CAH.

Molecular diagnosis of Chinese patients with 21-hydroxylase deficiency and analysis of genotype-phenotype correlations

Objective The spectrum of molecular defects in Chinese patients with 21-hydroxylase deficiency (21-OHD), and genotype-phenotype relationships are unknown. Methods We screened eight patients with non-classical (NC) 21-OHD and 35 with classical 21-OHD, and detected nine known mutations. Results The most frequent mutation among the 43 21-OHD cases was p.Ile172Asn (allele frequency, 36.0%), followed by c.290-13A/C > G (20.9%), Del (8.6%), p.Pro30Leu (7.0%), p.Gln318Ter (7.0%), p.Val281Leu (4.7%), p.Arg356Trp (2.3%), p.[Ile236Asn; Val237Glu; Met239Lys] (2.3%), and E3Δ8 bp (1.2%). The frequency spectrum of CYP21A2 mutations in the Chinese population was similar to that in the Japanese population, except that p.Val281Leu was identified in Chinese NC21-OHD patients at a frequency of 25.0%, whereas it was absent in Japanese patients. We found that genotype could predict phenotype in 88.3% of patients. Conclusion Some characteristics appear to be unique to the Chinese population, but genotype was strongly predictive of phenotype.

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.

Association of HLA alleles and haplotypes with CYP21A2 gene p. V282L mutation in the Croatian population

The CYP21A2 mutations that are in linkage disequilibrium with particular HLA-A, -B, -DRB1 alleles/haplotypes, cause deficiency of the 21-hydroxylase enzyme (21-OHD) and account for the majority of congenital adrenal hyperplasia (CAH) cases. The aim of this study was to investigate those associations with the p.V282L mutation linked to the non-classical (NC) form of CAH among Croatians. The study included parents of patients with the NC form of CAH, positive for the p.V282L mutation (N = 55) and cadaveric donor samples (N = 231). All subjects were HLA-A, -B, and -DRB1 typed and tested for the presence of the p.V282L mutation. Among parents of patients, 92.73% of subjects were positive for the B*14:02 allele and almost half of them carried the HLA-A*33:01-B*14:02-DRB1*01:02 haplotype. Among cadaveric samples 77 out of 96 subjects positive for the B*14:02 allele had the p.V282L mutation. Among them, 37 were positive for the HLA-A*33:01-B*14:02-DRB1*01:02 haplotype, 23 had the HLA-A*33:01-B*14:02-DRB1*03:01 haplotype, 8 had the B*14:02-DRB1*01:02 combination and 5 were carrying the HLA-A*68:02-B*14:02-DRB1*13:03 haplotype. Only 4 of these subjects were positive for the B*14:02 allele. HLA-B*14:02 was the only single allele with association that reached statistically significant P value (RR = 12.00; P = 0.0024). Haplotypes B*14:02-DRB1*01:02 (P < 0.001) and HLA-A*68:02-B*14:02-DRB1*13:03 (P < 0.001) as well as HLA-A*33:01-B*14:02-DRB1*01:02 and HLA-A*33:01-B*14:02-DRB1*03:01 showed high relative risks (RR = 45.00, RR = 41.63 and RR = 36.96, respectively). Our data support the previously documented association of the HLA-A*33:01-B*14:02-DRB1*01:02 haplotype with the p.V282L mutation, but also point out a high frequency of the p.V282L mutation among Croatians with HLA-A*33:01-B*14:02-DRB1*03:01 and HLA-A*68:02-B*14:02-DRB1*13:03 haplotypes.

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.

[Genotypes and phenotypes in Uygur children with 21-hydroxylase deficiency in Xinjiang, China]

OBJECTIVE

To investigate gene mutations and the relationship between genotypes and clinical phenotypes in Uygur children with 21-hydroxylase deficiency (21-OHD) in Xinjiang, China.

METHODS

A total of 20 Uygur children with 21-OHD who visited the hospital between October 2013 and October 2014 were enrolled. Full-length direct sequencing and multiplex ligation-dependent probe amplification (MLPA) were used to detect the mutations of CYP21A2 gene, which encoded 21-hydroxylase. According to the type of mutation, the patients with 21-OHD were divided into different groups to analyze the consistency between predicted clinical phenotypes and actual clinical phenotypes.

RESULTS

A total of 9 mutation types were found in the 20 patients, and 8 of them were identified as pathogenic mutations, i.e., Del, conv, I2g, I172N, Cluster E6, 8-bp del, V281L, and R356W. The other mutation is the new mutation occurring in intron 5 (c.648+37A>G), which had not been reported, and its pathological significance remains unknown. Most clinical phenotypes predicted by mutation types had a higher coincidence rate with actual clinical phenotypes (above 67%), and the clinical phenotypes predicted by P30L and V281L had a lower coincidence rate with actual clinical phenotypes (below 33%).

CONCLUSIONS

The genotype of 21-OHD has a good correlation with phenotype, and the clinical phenotype can be predicted by detecting the patient&prime;s genotype. The new mutation (c.648+37A>G) may be related to the pathogenesis of 21-OHD.

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.

Genotype in the diagnosis of 21-hydroxylase deficiency: who should undergo CYP21A2 analysis?

AIMS

to confirm the diagnosis of 21-hydroxylase deficiency (21-OHD) by the analysis of CYP21A2 gene in infants with clinical and/or biochemical features of 21-OHD in order to clarify which patients to submit to genetic analysis; to analyze the genotype-phenotype concordance in these infants.

SUBJECTS AND METHODS

We studied 25 children with clinical and/or biochemical features of 21-OHD. All of them and their parents were submitted to genetic analysis of CYP21A2. Patients were classified in 3 groups according to mutations' severity: severe (group A), moderate (group B) or mild (group C).

RESULTS

CYP21A2 gene mutations were found in 17 children. Whereas all infants of groups A and B presented a classical form of 21- OHD, children of group C had a non-classical form of 21-OHD. Four infants resulted heterozygotes and 4 children were wildtype. A girl clinically presenting a non-classical form of 21-OHD resulted compound heterozygote with one of the mutations not described in literature (R25W) and whose residual enzymatic activity is not already known. All affected children presented a 17-OHP level after ACTH stimulation greater than 100 nmol/l. We found an optimal concordance between 17-OHP levels after ACTH test and genotype.

CONCLUSIONS

CYP21A2 analysis permitted to confirm the diagnosis of 21-OHD in 68% of our children. To improve this percentage we suggest to perform the CYP21A2 analysis only when 17-OHP after ACTH test is greater than 100 nmol/l. Moreover, we found an optimal genotype-phenotype concordance in the 21-OHD patients.

A sequence variation in 3'UTR of CYP21A2 gene correlates with a mild form of congenital adrenal hyperplasia

BACKGROUND

Congenital adrenal hyperplasia (CAH) is mainly caused by the deficiency of the 21-hydroxylase enzyme coded by the CYP21A2 gene. However, some alleles in the non-classical form (NC-CAH) remain without identified mutations, suggesting the involvement of regulatory regions.

AIM

Our objective was to study an allele carrying the variant *13 G>A in the 3'UTR of the CYP21A2 gene identified in some patients with a mild form of NC-CAH in order to verify the possible implication of this variation with the phenotype observed.

SUBJECTS AND METHODS

Among all the subjects in whom the CYP21A2 gene was analyzed, 14 patients and 7 relatives heterozygous or homozygous for the *13 G>A substitution in 3'UTR were selected. Sequencing of DNA, genotyping, multiplex ligation-dependent probe amplification (MLPA), in vitro studies and bioinformatic analysis were performed.

RESULTS

The haplotype of the *13 G>A allele was identical in all the subjects with a monomodular structure composed by one C4A gene and one CYP21A2 gene without a second module with the CYP21A1P pseudogene. No other concomitant mutations were found in the region extending from 3 kb in the promoter and encompassing the polyadenylation signal. Both bioinformatic analysis and in vitro studies predicted an alteration of the RNA folding and expression, but no miRNA target sequences were found in this region.

CONCLUSIONS

The identification of a substitution in the 3'UTR of the gene associated with a mild form of NC-CAH suggests the importance of analyzing the CYP21A2 untranslated regions to better characterize and treat this subgroup of patients.

Genotype, phenotype and hormonal levels correlation in non-classical congenital adrenal hyperplasia

Non-classical congenital adrenal hyperplasia (NCAH) is a morbid condition sustained by the reduced function of one of the enzymes involved in the adrenal steroid biosynthesis pathway, mainly the 21-hydroxylase. Different degrees of enzyme activity impairment determine different clinical pictures, with childhood or post-pubertal onset. The aim of this study was to evaluate the relationship between genotype, phenotype, and adrenal hormonal levels in a group of 66 patients affected by NCAH attending outpatient pediatric or endocrinological Clinics. Our findings show that age at pubarche/menarche was significantly younger, height SD score) and Δ bone age-chronological age were significantly higher in patients with a more severe enzyme activity impairment, while cutaneous androgenization and menstrual irregularities in post-pubertal girls were not related to the grading of genotype.

Congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency: an Endocrine Society clinical practice guideline

OBJECTIVE

We developed clinical practice guidelines for congenital adrenal hyperplasia (CAH).

PARTICIPANTS

The Task Force included a chair, selected by The Endocrine Society Clinical Guidelines Subcommittee (CGS), ten additional clinicians experienced in treating CAH, a methodologist, and a medical writer. Additional experts were also consulted. The authors received no corporate funding or remuneration.

CONSENSUS PROCESS

Consensus was guided by systematic reviews of evidence and discussions. The guidelines were reviewed and approved sequentially by The Endocrine Society's CGS and Clinical Affairs Core Committee, members responding to a web posting, and The Endocrine Society Council. At each stage, the Task Force incorporated changes in response to written comments.

CONCLUSIONS

We recommend universal newborn screening for severe steroid 21-hydroxylase deficiency followed by confirmatory tests. We recommend that prenatal treatment of CAH continue to be regarded as experimental. The diagnosis rests on clinical and hormonal data; genotyping is reserved for equivocal cases and genetic counseling. Glucocorticoid dosage should be minimized to avoid iatrogenic Cushing's syndrome. Mineralocorticoids and, in infants, supplemental sodium are recommended in classic CAH patients. We recommend against the routine use of experimental therapies to promote growth and delay puberty; we suggest patients avoid adrenalectomy. Surgical guidelines emphasize early single-stage genital repair for severely virilized girls, performed by experienced surgeons. Clinicians should consider patients' quality of life, consulting mental health professionals as appropriate. At the transition to adulthood, we recommend monitoring for potential complications of CAH. Finally, we recommend judicious use of medication during pregnancy and in symptomatic patients with nonclassic CAH.

A p.P30L Mutation at the CYP21A2 Gene in Macedonian Patients with Nonclassical Congenital Adrenal Hyperplasia

Nonclassical congenital adrenal hyperplasia (NCAH) is an autosomal recessive imbalance in cortisol synthesis with adrenal androgen excess. Although rarely recognized in infants, it may cause premature adrenarche and pubarche, virilization in young women and variable symptoms in young men. It is commonly caused by mutations in CYP21A2, the gene for steroid 21-hydroxylase. Patients with the p.P30L allele tend to have pronounced evidence of androgen excess but are categorized as nonclassical. We used direct molecular detection of the p.P30L mutation in CYP21A2 in 11 Macedonian NCAH patients and in 17 members of their families using polymerase chain reaction/amplification created restriction site (PCR/ACRS) analysis and digestion with restriction enzymes. The p.P30L mutation was found in a homozygous state in seven (63.6%) and in a heterozygous state in four (36.4%) patients. Of the latter, one was also heterozygous for the p.Q318X mutation. The p.P30L mutation was found in a heterozygous state in 10 (58.8%) and in a homozygous state in one (5.9%) of the family members. These findings support a role of the p.P30L mutation in NCAH.

Nonclassic adrenal hyperplasia

Nonclassic adrenal hyperplasia is most commonly attributable to mutations in CYP21A2 (also termed CYP21) encoding steroid 21-hydroxylase. Partial deficiency of this enzyme causes an imbalance in cortisol synthesis with consequent adrenal androgen excess. Unlike more severe forms of congenital adrenal hyperplasia, this condition is rarely recognized in infants, but rather is a potential cause of premature adrenarche and pubarche in children, virilization in young women, and variable symptoms in young men. This article will review relevant clinical, hormonal and genetic aspects of nonclassic adrenal hyperplasia.

Salt-wasting congenital adrenal hyperplasia: genotypical peculiarities in a Sicilian ethnic group

Here we report for the first time the results of the molecular study of 17 unrelated patients with salt-wasting (SW) congenital adrenal hyperplasia (CAH) belonging to a Sicilian ethnic group, as corroborated by patients' pedigree taken to include 2 generations in the paternal and maternal lineage. The aim of this report was to confirm that genetic basis of CAH may be characterized by population differences. In our series, the overall predominant mutation was IVS2A/C>G, that was detected in 50% of alleles and in 58.8% of patients. The allelic and homozygous frequencies of IVS2A/C>G, Del8bpE3, and R356W mutations were significantly higher in our series than in other populations. Our study population included 2 cases with 2 different mutations that have been recently reported for the first time, 3 cases with a double mutation on the same allele, and 1 case with homozygous de novo mutation. We concluded that: a) in a Sicilian ethnic group the most frequent genotype in SW CAH is IVS2A/C>G homozygocity; b) surprisingly Del8bpE3 and R256W homozygocity are also well represented.

High frequency of copy number variations and sequence variants at CYP21A2 locus: implication for the genetic diagnosis of 21-hydroxylase deficiency

BACKGROUND

The systematic study of the human genome indicates that the inter-individual variability is greater than expected and it is not only related to sequence polymorphisms but also to gene copy number variants (CNVs). Congenital Adrenal Hyperplasia due to 21-hydroxylase deficiency (21OHD) is the most common autosomal recessive disorder with a carrier frequency of 1:25 to 1:10. The gene that encodes 21-hydroxylase enzyme, CYP21A2, is considered to be one of the most polymorphic human genes. Copy number variations, such as deletions, which are severe mutations common in 21OHD patients, or gene duplications, which have been reported as rare events, have also been described. The correct characterization of 21OHD alleles is important for disease carrier detection and genetic counselling

METHODOLOGY AND FINDINGS

CYP21A2 genotyping by sequencing has been performed in a random sample of the Spanish population, where 144 individuals recruited from university students and employees of the hospital were studied. The frequency of CYP21A2 mutated alleles in our sample was 15.3% (77.3% were mild mutations, 9% were severe mutations and 13.6% were novel variants). Gene dosage assessment was also performed when CYP21A2 gene duplication was suspected. This analysis showed that 7% of individuals bore a chromosome with a duplicated CYP21A2 gene, where one of the copies was mutated.

CONCLUSIONS

As far as we know, the present study has shown the highest frequency of 21OHD carriers reported by a genotyping analysis. In addition, a high frequency of alleles with CYP21A2 duplications, which could be misinterpreted as 21OHD alleles, was found. Moreover, a high frequency of novel genetic variations with an unknown effect on 21-hydroxylase activity was also found. The high frequency of gene duplications, as well as novel variations, should be considered since they have an important involvement in carrier testing and genetic counseling.

The role of 21-hydroxylase in the pathogenesis of adrenal masses: review of the literature and focus on our own experience

An exaggerated response of 17- hydroxyprogesterone (17-OHP) to exogenous ACTH stimulation has been found in 30 to 70% of patients with incidentally discovered adrenal tumors, supporting the concept that congenital 21- hydroxylase deficiency may be a predisposing factor for adrenocortical tumorigenesis. Decreased expression of 21-hydroxylase gene has been observed in sporadic non-functioning adrenocortical adenomas and adrenocortical carcinomas, in agreement with the reduced steroidogenic activity found in these types of tumors. Screening studies for the presence of mutations in CYP21A2 gene, encoding 21-hydroxylase, in patients with sporadic adrenocortical tumors yielded discordant results. Overall, a higher frequency of germline 21-hydroxylase mutation carriers has been found among patients with adrenal tumors, including incidentalomas, than in the general population. However, the presence of mutations did not correlate with endocrine test results and tumor mass features, suggesting that 21-hydroxylase deficiency does not represent a relevant mechanism in adrenal tumorigenesis. Mechanisms leading to reduced 21-hydroxylase expression and activity are still unknown.

Ethnic-specific distribution of mutations in 716 patients with congenital adrenal hyperplasia owing to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) occurs worldwide. The most common mutations in the CYP21A2 gene in 716 unrelated patients were analyzed and the mutations were grouped by ethnicity, as defined through self-declaration corroborated by review of pedigrees extending to two or three generations. Prevalent allelic mutations and genotypes were found to vary significantly among ethnic groups, and the predominance of the prevalent mutations and genotypes in several of these populations was significant. There are ethnic-specific mutations in the CYP21A2 gene. A large deletion is prevalent in the Anglo-Saxons; a V281L (1685 G to T) mutation is prevalent in Ashkenazi Jews; an R356W (2109 G to A) mutation is prevalent in the Croatians; an IVS2 AS -13 (A/C to G) mutation is prevalent in the Iranians and Yupik-speaking Eskimos of Western Alaska; and a Q318X (1994 C to T) mutation is prevalent in East Indians. Genotype/phenotype non-correlation was seen when at least one IVS2 AS -13 (A/C to G) mutation in the CYP21A2 gene was present.

In Sicilian ethnic group non-classical congenital adrenal hyperplasia is frequently associated with a very mild genotype

The spectrum of mutated alleles in non-classical congenital adrenal hyperplasia (NC-CAH) has been recently reported to be very large and haplotypes may significantly differ in the different ethnic groups. In order to confirm that population differences may exist in the genetic basis of this disease, we have analyzed the genetic presentation of NC-CAH in a Sicilian cohort of symptomatic patients and compared our findings with the ones reported in other studies of different ethnic groups. In 38 NC-CAH patients coming from two regions of Sicily and born of Sicilian parents, we found that 84.2% of the chromosomes examined bore only mild mutations and only the remaining 15.8% of the chromosomes bore at least 1 severe mutation. The overall predominant mutation was V281L, which was detected in 73.7% of alleles and in 89.5% of patients. About 58% of the patients were homozygotes for this mutation. V281L allele and homozygote frequencies were higher in the present series than in other European and Italian reports. In our NC-CAH population, which is one of the largest ever reported, the patients with two mild mutations exhibited a less severe impairment of both clinical and endocrine phenotype. On the basis of these results we can conclude that: a) in Sicilian ethnic groups NC-CAH is frequently associated with a very mild genotype; b) the most frequent genotype in our series is V281L homozygosis; c) clinical and biochemical expression of NC-CAH is more marked in the patients bearing a severe mutation; d) no correlations between genotype and phenotype were found in our patients affected by NC-CAH.

Molecular Analysis of a Family With Congenital Adrenal Hyperplasia - Genotype/Phenotype Discrepancy

Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disease with a variable clinical presentation caused by a spectrum of different mutations. A significant association of genotype with phenotype has been reported.

The molecular analysis of a girl with a mild form of CAH presenting with precocious pubarche, confirmed that she was heterozygous for two mutations of the CYP21 gene (exon 1, codon 30/exon 8, codon 318). Her mother was homozygous for the codon 30 mutation and her father was homozygous for the codon 318 mutation. The only anomaly in the parents was a difficulty in conceiving. The molecular analysis of this family confirmed the variability of presentation in carriers of different mutations, which caused difficulties in decisions about the timing of therapy and in genetic counseling.

Molecular model of human CYP21 based on mammalian CYP2C5: structural features correlate with clinical severity of mutations causing congenital adrenal hyperplasia

Enhanced understanding of structure-function relationships of human 21-hydroxylase, CYP21, is required to better understand the molecular causes of congenital adrenal hyperplasia. To this end, a structural model of human CYP21 was calculated based on the crystal structure of rabbit CYP2C5. All but two known allelic variants of missense type, a total of 60 disease-causing mutations and six normal variants, were analyzed using this model. A structural explanation for the corresponding phenotype was found for all but two mutants for which available clinical data are also discrepant with in vitro enzyme activity. Calculations of protein stability of modeled mutants were found to correlate inversely with the corresponding clinical severity. Putative structurally important residues were identified to be involved in heme and substrate binding, redox partner interaction, and enzyme catalysis using docking calculations and analysis of structurally determined homologous cytochrome P450s (CYPs). Functional and structural consequences of seven novel mutations, V139E, C147R, R233G, T295N, L308F, R366C, and M473I, detected in Scandinavian patients with suspected congenital adrenal hyperplasia of different severity, were predicted using molecular modeling. Structural features deduced from the models are in good correlation with clinical severity of CYP21 mutants, which shows the applicability of a modeling approach in assessment of new CYP21 mutations.

High variability in CYP21A2 mutated alleles in Spanish 21-hydroxylase deficiency patients, six novel mutations and a founder effect

OBJECTIVE

To detect common as well as rare and novel CYP21A mutations in 21-hydroxylase deficiency patients. To estimate the distribution of mutations and compare them with other European studies. To construct haplotypes linked to a recurrent novel mutation.

DESIGN

Genetic analysis by sequencing the entire CYP21A2 gene plus Southern blot.

PATIENTS

A total of 138 unrelated Spanish patients: 122 nonclassical forms (NCF) and 16 classical forms (CF) were studied.

RESULTS

Among the 266 nonrelated mutated alleles; CYP21A2 deletions/conversions and a spectrum of 27 different mutated alleles were found: 15 different single point mutations, 8 nucleotide deletions in exon 3, 3 mutation clusters in exon 6, 9 alleles with more than one mutation, one 21-nucleotide duplication in exon 10, and one allele with CYP21A2 duplicated and both copies mutated. The most frequent mutation in NCF alleles is V281L (71.8%). Among CFs, the most common is I2 g (20%) and Q318X (16%) and rare alleles (21.9%). Six novel causative mutations were found, four associated with CF: I46+1nt, R444X, P463L and M473_R479dup and two associated with NCF: W302 and D322G. The R444X mutation was found in seven unrelated patients and it appeared only once in an ancestral haplotype. In addition, we found a novel single nucleotide polymorphism with a 31.5% frequency for the rare allele.

CONCLUSION

A great diversity of haplotypes with a large spectrum of mutated alleles was found. The frequency of the V281L mutation was the highest reported and the relatively high frequency of R444X was the result of a founder effect.

Mutational spectrum of steroid 21-hydroxylase and the genotype-phenotype association in Middle European patients with congenital adrenal hyperplasia

OBJECTIVE

To analyze the mutational spectrum of steroid 21-hydroxylase (CYP21) and the genotype- phenotype correlation in patients with congenital adrenal hyperplasia (CAH) registered in the Middle European Society for Pediatric Endocrinology CAH database, and to design a reliable and rational approach for CYP21 mutation detection in Middle European populations.

DESIGN AND METHODS

Molecular analysis of the CYP21 gene was performed in 432 CAH patients and 298 family members. Low-resolution genotyping was performed to detect the eight most common point mutations. High-resolution genotyping, including Southern blotting and sequencing was performed to detect CYP21 gene deletions, conversions, point mutations or other sequence changes.

RESULTS

CYP21 gene deletion and In2 and Ile172Asn mutation accounted for 72.7% of the affected alleles in the whole study group. A good genotype-phenotype correlation was observed, with the exception of Ile172Asn and Pro30Leu mutations. In 37% of patients low resolution genotyping could not identify the causative mutation or distinguish homozygosity from hemizygosity. Using high-resolution genotyping, the causative mutations could be identified in 341 out of 348 analyzed patients. A novel mutation Gln315Stop was found in one simple virilising CAH (SV-CAH) patient from Austria. In the remaining seven patients polymorphisms were identified as the leading sequence alteration. The presence of elevated basal and ACTH-stimulated 17-hydroxyprogesterone, premature pubarche, advanced bone age and clitoral hypertrophy directly implicated Asn493Ser polymorphism in the manifestation of nonclassical- (NC) and even SV-CAH.

CONCLUSIONS

By genotyping for the most common point mutations, CYP21 gene deletion/conversion and the 8 bp deletion in exon 3, it should be possible to identify the mutation in 94-99% of the diseased alleles in any investigated Middle European population. In patients with a mild form of the disease and no detectable mutation CYP21 gene polymorphisms should be considered as a plausible disease-causing mutation.

CYP21 genotype, adult height, and pubertal development in 55 patients treated for 21-hydroxylase deficiency

In a retrospective study we evaluated long-term growth, pubertal developmental patterns to final height (FH), and medication in 55 patients (35 females) affected by 21-hydroxylase deficiency. The patients were classified into 3 groups according to predicted mutation severity: group A (11 women and 9 men), homozygous or compound heterozygous for null or In2 splice mutations [residual enzymatic activity (RA), <1%]; group B (11 women and 4 men), homozygous for I172N or R341P or R426H mutations (RA, approximately 2-3%) or compound heterozygous with any of the group A or B mutations; and group C (13 women and 7 men), homozygous for P30L or V281L or P453S mutations (RA, >30%) or compound heterozygous with any of the group A, B, or C mutations. Three patients showed unclassifiable genotypes. FH was similar in the female groups, whereas male patients in group B were shorter than males in groups A and C. Fifty-five percent of patients in group A, 33% in group B, and 40% in group C reached an FH within 0.5 SD of target height. Four of the 7 patients diagnosed via neonatal screening achieved an FH equal to or above the target height. In the entire group, early diagnosis (<1 yr) improved height outcome. Early diagnosed CAH patients who received lower cortisol equivalent doses during the first year of life reached a better FH. Our results underline the importance of mineralocorticoid therapy, as CAH subjects in groups A and B who did not receive this treatment showed reduced FH. Early diagnosis, the use of more physiological cortisol equivalent dosages during the first year of life, and the extension of mineralocorticoid therapy to all classical patients are shown to improve the auxological outcome. Genotypic analysis helped to interpret the height results of our cases and prospectively may represent a useful tool for improving the therapeutic choice and the height outcome.

The ratio of second- and fourth-digit lengths and congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency results in excessive androgen exposure in the gestational period and various degrees of masculinization of the external genitalia in female foetuses. Intrauterine gonadal steroids are not only essential for the development of the genital organs but also affect some other extragenital organ development. The second to fourth digit (2D/4D) ratio shows a sexually dimorphic pattern with longer fourth digit from second digit in men compared to women. A low 2D/4D ratio is associated with high sperm count, testosterone levels and reproductive success in men. A high 2D/4D ratio is associated with high oestrogen levels in women. Second and fourth digit ratio has also found to be correlated with sexual orientation, left hand preference autism and some adult onset diseases such as breast cancer and myocardial infarction. We found lower 2D/4D ratio in female patients with 21-hydroxylase deficiency compared to healthy girls (p=0.000) and equal 2D/4D ratio for female patients when compared to male controls. Male patients with 21-hydroxylase deficiency had significantly lower 2D/4D ratio than female and male controls in the right hand. Healthy boys had lower 2D/4D ratio than healthy girls. It is concluded that 2D/4D ratio established by intrauterine androgen levels influences the sexually dimorphic digit pattern.

Mutational analysis and genotype-phenotype correlation in patients with classic 21-hydroxylase deficiency from transylvania (north-west Romania)

The regional incidence of 21-hydroxylase deficiency, its mutational spectrum and the correlation of genotype and phenotype has been studied by European, American and Latin-American groups. However, little information is known about the molecular background of the disease in patients from Central-Eastern Europe. The present study aimed to genotype a group of patients from Transylvania, the north-western part of Romania, in order to gain some insight into the molecular pattern and the genotype-phenotype correlation of congenital adrenal hyperplasia (CAH) in this region. We genotyped 17 patients with classic 21-hydroxylase deficiency and, whenever available, their parents in order to verify mutational segregation. The patients came from 13 unrelated families. DNA was prepared from peripheral blood leucocytes and four gene fragments were amplified by PCR. The 21-hydroxylase gene (CYP21B) was completely sequenced and analyzed for point mutations or deletions. Percentage distribution of mutations was as follows: 12G--34.6%, deletions and large conversions (del)--19.2%, P30L--15.4%, 1172N--15.4%, P30L+I2G+del8bp (triple mutation)--11.5%, and R356W--3.8%. Mutational percentage distribution compared to other Latin populations is higher for I2G and I172N and lower for deletions, while the P30L mutation was found at a higher rate than in any other analyzed population. Some differences may arise from the low patient number and from ethnic particularities. The incidence of compound heterozygotes in our group was 76.5%. The genotype seemed to correlate fairly well to phenotype, with a general concordance rate of 82.35%. Clear divergence was found in two patients with the simple virilizing form, exhibiting a homozygous status for I2G and del, respectively. This study offers the first information about the molecular pathology of CAH in Romania and should help to improve management and clinical outcome for patients with CAH in Transylvania. Hopefully, it might also be the first step towards exact and accurate prenatal diagnosis in our country.

Molecular diagnosis of CYP21 mutations in congenital adrenal hyperplasia: implications for genetic counseling

Congenital adrenal hyperplasia (CAH) is an inherited disorder of steroid biosynthesis most often attributable to mutations in CYP21 (also termed CYP21A2) encoding the active steroid 21-hydroxylase enzyme. This review focuses on clinical and genetic aspects of CAH, and updates the reader on current methodology and applications for molecular genetic diagnosis. Genotyping patients with CAH has revealed > 50 mutations within CYP21, yet only 10 mutations account for approximately 95% of affected alleles. Many CYP21 mutations are gene conversions arising via transfer of gene sequences between the non-functional CYP21 pseudogene and CYP21. Phenotype is generally well-correlated with genotype. Historically, CAH has been divided into 3 types of disease: classic salt-wasting, classic simple virilizing (non-salt-wasting), and nonclassic. Recent findings support the notion that rather than discrete phenotypic categories, CAH is better represented as a continuum of phenotypes, from severe to mild. Molecular genetic diagnosis is most effectively employed now in prenatal diagnosis of classic CAH. As newborn screening for CAH becomes more widespread, genotyping may be implemented to resolve diagnostic difficulties encountered with hormonal testing. As automated methods of DNA diagnosis such as microarrays or gene chips are refined, it is likely that genetic screening will become less expensive and more readily available. The clinician should be aware of the potential for both false negatives and false positives with PCR-based gene screening. In short, whereas molecular genetic diagnosis is a valuable tool, it cannot replace clinical acumen and hormonal assays.

Classical and nonclassical 21-hydroxylase deficiency: a molecular study of Argentine patients

OBJECTIVE

To characterize the molecular basis of the 21-hydroxylase deficiency in a group of Argentine patients presenting the classical and nonclassical forms of the disease.

DESIGN

To analyse the frequency of point mutations in the CYP21 gene by DNA amplification and mutation detection.

PATIENTS

Forty-one patients from 36 nonrelated families: 25 nonclassical (NC), 11 salt-wasting (SW) and five simple virilizing (SV). A total of 27 parents and 13 nonaffected siblings were also analysed.

MEASUREMENTS

Basal steroid hormones and 17-hydroxyprogesterone levels following adrenal stimulation with adrenocorticotrophic hormone were measured, together with an analysis of 10 point mutations in the CYP21 gene.

RESULTS

A total of 83% and 74.4% classical and nonclassical chromosomes, respectively, were characterized. The intron 2 mutation was the most prevalent among classical alleles. In addition, a high frequency for R356W was observed in both groups (13.3 and 6.9%, respectively), while V281L was the most frequent mutation among the nonclassical patients with a frequency of 39.5%. No alleles containing P30L were observed, and one de novo mutation (R356W) was found. A total of 68.3% patients were fully genotyped, and all but one showed no genotype/phenotype discrepancy. Though the cut-off value for post-ACTH 17-hydroxyprogesterone stimulation was 30.25 nmol/l (10.00 microg/l), the lowest value observed in the fully genotyped nonclassical group was 42.35 nmol/l (14.00 microg/l).

CONCLUSIONS

The high number of unidentified alleles in the nonclassical group suggests that less frequent mutations, or the presence of new ones, might be the cause of the disease in the Argentine population. Alternatively, the cut-off value in the ACTH-stimulated 17-hydroxyprogesterone test might overestimate the diagnosis of the nonclassical form by including some patients with heterozygous status.

Neonatal screening for congenital adrenal hyperplasia: 17-hydroxyprogesterone levels and CYP21 genotypes in preterm infants

OBJECTIVE

Neonatal screening for congenital adrenal hyperplasia (CAH) among preterm infants is complicated by the fact that healthy preterm infants have higher levels of 17-hydroxyprogesterone (17-OHP) than term infants, resulting in a higher false-positive rate. Even when gestational age-related cutoff levels after ether extraction were used, the false-positive cases primarily comprised preterm infants. The aim of the study was to optimize the procedure for neonatal screening for CAH in preterm infants.

METHODS

The 17-OHP levels in 6200 preterm infants were correlated to the gestational age. We also calculated the number of recalls for different putative cutoff levels of the 17-OHP by direct assay and after extraction in 1275 preterm infants who represented the most elevated cases in a population of approximately 30 000 preterm infants. The CYP21 genotypes and screening levels were determined in the 12 preterm infants with CAH diagnosed since the start of screening. The effect of possible interfering factors such as gestational age, neonatal stress, and prenatal glucocorticoid treatment for pulmonary maturation was studied.

RESULTS

The extraction procedure did not significantly improve the sensitivity or specificity of the screening, whereas it delayed the day of recall from 8 to 13 days (median). We could not demonstrate any systematic influence of the studied stress factors or the prenatal glucocorticoid treatment on the 17-OHP screening levels. In the patients with CAH, the 17-OHP levels correlated better with disease severity than with the degree of prematurity.

CONCLUSIONS

On the basis of these results, we omitted the extraction step and changed the cutoff levels in the Swedish screening program for preterm infants. We chose to use a cutoff level of 400 nmol/L plasma in infants who were born before week 35 and 150 nmol/L for infants who were born in weeks 35 and 36. For detecting more patients, the cutoff level would have to be much lower, which would result in a number of false-positive tests that we consider to be unacceptably high. It is clear that neonatal screening cannot detect all infants with CAH. Some milder forms of the disease, just like in the past, will have to be diagnosed on the basis of clinical signs and symptoms.

Newborn screening for congenital adrenal hyperplasia

Classic CAH (salt-wasting and simple virilizing) meets all of the recommended criteria for newborn screening. There are reliable and efficient newborn screening tests, the disorder results in high morbidity and mortality if left undetected, there is effective treatment that reduces negative outcomes, and there is a relatively high incidence. When compared with the case findings without the benefit of screening, the data from screening programs show reduced adrenal crises, reduced incorrect sex assignments, and reduced deaths. Racial/ethnic prevalence differences are present in newborn screening program data. The Texas data indicate a lower disease frequency in African-Americans when compared with Caucasians, and international data indicate higher frequencies in native Yupik Eskimos, Brazilians, residents of La Reunion, and Filipinos. When worldwide clinical ascertainment data are compared with newborn screenng data, it is clear that newborns with CAH (especially males) die when screening is not done. To be effective in reducing mortality, newborn screening must be performed soon after birth, and the results must be available quickly so that early salt-wasting crises can be averted. It is preferable that newborn screening laboratiories be operational 7 days a week, and that sample delivery from the collection site to testing laboratory be as efficient as possible, including weekends and holidays, so that undue testing delays are not encountered. These two requirements pose major challenges for most programs, but they are critical to optimal screening outcome. Based on the studies in Texas, with second screening samples collected at approximately 2 weeks of age, some newborns with simple virilizing CAH are missed on initial screening using current testing protocols. There is need to set a screening cut-off such that the false-positive rate does not oversaturate the follow-up system, in part owing to the insensitivity of current kit methodologies and the biochemical manifestations of CAH. With advances in genetic testing procedures and improved automation techniques, it may soon be possible for CAH screening programs to include genotyping as a second-tier confirmation as a part of the newborn screening protocol. Despite the fact that CAH is a continuum of disorders, the correlation between genotype and phenotype is fairly consistent in most cases. For the purpose of screening, genotyping will likely be useful only for differential diagnoses of non-salt wasters, given the necessary time constraints and expense of obtaining genotypes and the need for immediate diagnosis/treatment of salt wasters. It is hoped that newborn screening programs will begin to provide answers to some of these question in addition to their primary function of reducing the morbidity and mortality resulting from CAH.