Hormonal control during infancy and testicular adrenal rest tumor development in males with congenital adrenal hyperplasia: a retrospective multicenter cohort study

IMPORTANCE

Testicular adrenal rest tumors (TARTs), often found in male patients with congenital adrenal hyperplasia (CAH), are benign lesions causing testicular damage and infertility. We hypothesize that chronically elevated adrenocorticotropic hormone exposure during early life may promote TART development.

OBJECTIVE

This study aimed to examine the association between commencing adequate glucocorticoid treatment early after birth and TART development.

DESIGN AND PARTICIPANTS

This retrospective multicenter (n = 22) open cohort study collected longitudinal clinical and biochemical data of the first 4 years of life using the I-CAH registry and included 188 male patients (median age 13 years; interquartile range: 10-17) with 21-hydroxylase deficiency (n = 181) or 11-hydroxylase deficiency (n = 7). All patients underwent at least 1 testicular ultrasound.

RESULTS

TART was detected in 72 (38%) of the patients. Prevalence varied between centers. When adjusted for CAH phenotype, a delayed CAH diagnosis of >1 year, compared with a diagnosis within 1 month of life, was associated with a 2.6 times higher risk of TART diagnosis. TART onset was not predicted by biochemical disease control or bone age advancement in the first 4 years of life, but increased height standard deviation scores at the end of the 4-year study period were associated with a 27% higher risk of TART diagnosis.

CONCLUSIONS AND RELEVANCE

A delayed CAH diagnosis of >1 year vs CAH diagnosis within 1 month after birth was associated with a higher risk of TART development, which may be attributed to poor disease control in early life.

A novel 9 bp deletion (c.1271_1279delGTGCCCGCG) in exon 10 of CYP21A2 gene causing severe congenital adrenal hyperplasia

BACKGROUND

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder of adrenal steroidogenesis with a broad spectrum of clinical presentations, ranging from the severe classical salt-wasting (SW) and simple-virilizing (SV) form, to the mild nonclassical form. A large variety of CYP21A2 genotypes in correlation with phenotype have been described.

MATERIALS AND METHODS

DNA samples from a 14-day-old male newborn with clinical and laboratory signs of SW CAH and family members were subjected for molecular analysis of the nine most common point CYP21A2 mutations by ACRS/PCR method. Direct DNA sequencing of the whole CYP21A2 gene was performed to detect the second mutant allele in the patient. The in silico predicting analysis and the crystal structure analysis of the mutated CYP21A2 protein have been performed.

RESULTS

Molecular analysis confirmed that the patient was compound heterozygote carrying p.Q318X mutation inherited from the mother and a novel c.1271_1279delGTGCCCGCG (p.G424_R426del) variant in exon 10 inherited from the father. The in silico predicting software tools classified the novel mutation as pathogenic. Crystal structure analysis showed that the three residues affected by the novel in-frame deletion form several hydrogen bonds that could lead to impaired stability and function of the CYP21A2 protein. These findings were concordant with the patient's phenotype. The need of several molecular methods to elucidate the genotype in this patient has also been discussed.

CONCLUSIONS

A novel 9 bp deletion in CYP21A2 gene with predicted pathogenic effect on the enzyme activity was detected in neonatal patient causing severe SW CAH.

Steroid 21-hydroxylase gene variants and late-life depression

Objectives

A feature of late-life depression is alterations of the stress hormone system. The CYP21A2 gene encodes for the steroid 21-hydroxylase enzyme which is required for the biosynthesis of mineralocorticoids and glucocorticoids, two main components of the stress response in humans. Variants in the CYP21A2 gene could influence risk of late-life depression, but this has not been examined. This study investigated possible associations between five variants in the CYP21A2 gene and late-life depression in 1007 older community-dwelling men and women.

Results

In multivariate logistic regression model, significant associations were found between three single-nucleotide polymorphisms (rs389883, rs437179, and rs630379) and depression in women specifically (OR ranging from 1.51 to 1.68, p-values 0.025 to 0.0045), and the two latter remained significant after correction for multiple testing. Variants of the CYP21A2 gene appear as susceptibility factors for late-life depression in a sex-specific manner, independently of somatic and neuropsychiatric comorbidity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05616-6.

Finding branched pathways in metabolic network via atom group tracking

Finding non-standard or new metabolic pathways has important applications in metabolic engineering, synthetic biology and the analysis and reconstruction of metabolic networks. Branched metabolic pathways dominate in metabolic networks and depict a more comprehensive picture of metabolism compared to linear pathways. Although progress has been developed to find branched metabolic pathways, few efforts have been made in identifying branched metabolic pathways via atom group tracking. In this paper, we present a pathfinding method called BPFinder for finding branched metabolic pathways by atom group tracking, which aims to guide the synthetic design of metabolic pathways. BPFinder enumerates linear metabolic pathways by tracking the movements of atom groups in metabolic network and merges the linear atom group conserving pathways into branched pathways. Two merging rules based on the structure of conserved atom groups are proposed to accurately merge the branched compounds of linear pathways to identify branched pathways. Furthermore, the integrated information of compound similarity, thermodynamic feasibility and conserved atom groups is also used to rank the pathfinding results for feasible branched pathways. Experimental results show that BPFinder is more capable of recovering known branched metabolic pathways as compared to other existing methods, and is able to return biologically relevant branched pathways and discover alternative branched pathways of biochemical interest. The online server of BPFinder is available at http://114.215.129.245:8080/atomic/. The program, source code and data can be downloaded from https://github.com/hyr0771/BPFinder.

Computational search of branched metabolic pathways is a fundamental problem in metabolic engineering and metabolic network analysis, which provides a systematic way of understanding the metabolism and discovering alternative pathways for synthesis of useful biomolecules. We propose BPFinder, a novel computational approach to identify branched metabolic pathways via atom group tracking. Different from other pathfinding methods using atom tracking, BPFinder tracks the movement of atom groups in metabolic network to find linear atom group conserving pathways, and merge the found linear pathways by the selected branched compounds to generate branched pathways. Based on the structure of conserved atom groups in branched compounds, we design two merging rules for branched compounds: overlapping rule and non-overlapping rule. The user can flexibly adopt these rules to accurately find the branched pathways that contain overlapping/non-overlapping conserved atom groups. BPFinder also enables the user to combine the information of compound similarity, Gibbs free energy of reactions, and conserved atom groups to sort resulting pathways. Compared with other existing methods, BPFinder can more accurately recover the known branched pathways. The alternative branched pathways returned by BPFinder reveal that the user can flexibly utilize our proposed merging rules to discover biochemically meaningful pathways of interest.

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.

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

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

Zebrafish as a model for studying ovarian development: Recent advances from targeted gene knockout studies

Ovarian development is a complex process controlled by precise coordination of multiple factors. The targeted gene knockout technique is a powerful tool to study the functions of these factors. The successful application of this technique in mice in the past three decades has significantly enhanced our understanding on the molecular mechanism of ovarian development. Recently, with the advent of genome editing techniques, targeted gene knockout research can be carried out in many species. Zebrafish has emerged as an excellent model system to study the control of ovarian development. Dozens of genes related to ovarian development have been knocked out in zebrafish in recent years. Much new information and perspectives on the molecular mechanism of ovarian development have been obtained from these mutant zebrafish. Some findings have challenged conventional views. Several genes have been identified for the first time in vertebrates to control ovarian development. Focusing on ovarian development, the purpose of this review is to briefly summarize recent findings using these gene knockout zebrafish models, and compare these findings with mammalian models. These established mutants and rapid development of gene knockout techniques have prompted zebrafish as an ideal animal model for studying ovarian development.

A pilot study on newborn screening for congenital adrenal hyperplasia in Beijing

Background A provisionary screening programme for 21-hydroxylase deficiency (21-OHD) was initiated in Beijing in 2014. The aim of this study was to investigate the incidence and the associated clinical characteristics of neonatal congenital adrenal hyperplasia (CAH) in Beijing and to provide evidence-based guidance for its application in CAH screening. Methods Live birth newborns (n=44,360) were screened for CAH in Beijing from July 2014 to April 2018. The levels of 17-hydroxyprogesterone (17-OHP) in the blood were estimated using the time-resolved fluoroimmunoassay. Neonates with a positive result and a level >30 nmol/L of 17-OHP were called for a retest. CAH was diagnosed based on further laboratory findings combined with clinical signs, such as weight loss, feeding difficulties, skin pigmentation, and atypical genitalia. Through a review of medical records, the clinical findings including molecular data were reported. Results Of the 44,360 neonates screened, 280 cases were deemed positive. Of these, 203 neonates were recalled for further tests and six patients (three boys and three girls) were diagnosed with CAH. Five cases of classic salt-wasting and one case of simple virilising 21-OHD were identified. The incidence of CAH in Beijing was 1:7393. The most frequent 21-OHD mutation was c.293-13C/A>G. Conclusions The incidence of CAH in Beijing was higher than the national average. The results support the need for neonatal CAH screening in Beijing. This pilot study demonstrates the clinical characteristics of 21-OHD through newborn screening. Early detection and treatment through neonatal screening may reduce mortality rates and optimise developmental outcomes.

Identification of a novel compound heterozygous mutation of the CYP21A2 gene causing 21‑hydroxylase deficiency in a Chinese pedigree

21‑Hydroxylase deficiency (21‑OHD) is the most common cause of congenital adrenal hyperplasia. Inherited in an autosomal recessive manner, 21‑OHD is caused by mutations in the cytochrome P450 family 21 subfamily A member 2 (CYP21A2) gene. The present study was designed to investigate the genetic characteristics of one Chinese pedigree and to identify the genotype‑phenotype association, thereby facilitating the precise diagnosis of 21‑OHD at the molecular level. Members of a Chinese family with 21‑OHD were screened for mutations in the CYP21A2 gene. Clinical data and biochemical parameters, including androgen and derivatives, were collected. Complete DNA sequencing and multiplex ligation‑dependent probe amplification (MLPA) were utilized to analyze the genetic variations in the full‑length CYP21A2 gene. A C‑T transition located in exon 8 of the CYP21A2 gene, leading to the predicted amino acid residue change from Arg to Trp at codon 342, was identified in the mother and four sisters. Additionally, heterozygous deletion mutations of exons 1, 3, 4, 6 and 7 of paternal origin were detected in the four sisters by MLPA analysis. During the one‑year follow‑up, the four sisters exhibited symptom improvement following treatment with glucocorticoids, and the proband and one sister successfully conceived. The results of the present study demonstrated that novel compound heterozygous variations in the CYP21A2 gene may be causative agents of 21‑OHD, providing insights into the functions of this gene and a more comprehensive understanding of the disorder.

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.

CYP21A2 intronic variants causing 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder mainly caused by defects in the steroid 21-hydroxylase gene (CYP21A2). Most of CYP21A2 mutations result from intergenic recombinations between CYP21A2 and closely linked CYP21A1P pseudogene. Rare mutations not generated by gene conversion account for 5-10% of 21-hydroxylase deficiency alleles. Intronic variants represent only a little part of these but their effect on the protein is generally deleterious. The aim of this paper is to provide a comprehensive literary review regarding all intronic CYP21A2 pathological variants reported to date. In addition, we describe three novel causing disease variants in our patients affected by the classic form of CAH: IVS4-1G>A, IVS5-8T>A, IVS8-2A>G. In silico analysis revealed that all these substitutions affect the splicing process leading to a non-functional protein. Based on these results, we are able to classify them as pathological variants according to the patient's phenotype.

Structure-based activity prediction of CYP21A2 stability variants: A survey of available gene variations

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency accounts for 90-95% of CAH cases. In this work we performed an extensive survey of mutations and SNPs modifying the coding sequence of the CYP21A2 gene. Using bioinformatic tools and two plausible CYP21A2 structures as templates, we initially classified all known mutants (n = 343) according to their putative functional impacts, which were either reported in the literature or inferred from structural models. We then performed a detailed analysis on the subset of mutations believed to exclusively impact protein stability. For those mutants, the predicted stability was calculated and correlated with the variant's expected activity. A high concordance was obtained when comparing our predictions with available in vitro residual activities and/or the patient's phenotype. The predicted stability and derived activity of all reported mutations and SNPs lacking functional assays (n = 108) were assessed. As expected, most of the SNPs (52/76) showed no biological implications. Moreover, this approach was applied to evaluate the putative synergy that could emerge when two mutations occurred in cis. In addition, we propose a putative pathogenic effect of five novel mutations, p.L107Q, p.L122R, p.R132H, p.P335L and p.H466fs, found in 21-hydroxylase deficient patients of our cohort.

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.

Molecular genetic study of congenital adrenal hyperplasia in Serbia: novel p.Leu129Pro and p.Ser165Pro CYP21A2 gene mutations

PURPOSE

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease characterized by impaired adrenal steroidogenesis and most often caused by CYP21A2 gene mutations. For the first time, we reported complete spectrum and frequency of CYP21A2 gene mutations in 61 unrelated patients with classical and non-classical CAH from Serbia.

METHODS

Direct DNA sequencing of whole CYP21A2 gene and polymerase chain reaction with sequence-specific primers for detection of CYP21A1P/CYP21A2 chimeras were combined.

RESULTS

We identified 18 different pathogenic alleles-two of them novel. Mutation detection rate was highest in patients with salt-wasting form of CAH (94.7%). The most prevalent mutation was intron 2 splice site mutation, c.290-13A/C>G (18.5%). Other mutation frequencies were: CYP21A1P/CYP21A2 chimeras (13%), p.P30L (13%), p.R356W (11.1%), p.G110fs (7.4%), p.Q318X (4.6%), p.V281L (4.6%), p.I172N (2.8%), p.L307fs (2.8%), p.P453S (1.9%), etc. Mainly, frequencies were similar to those in Slavic populations and bordering countries. However, we found 6.5% of alleles with multiple mutations, frequently including p.P453S. Effects of novel mutations, c.386T>C (p.Leu129Pro) and c.493T>C (p.Ser165Pro), were characterized in silico as deleterious. The effect of well-known mutations on Serbian patients' phenotype was as expected.

CONCLUSIONS

The first comprehensive molecular genetic study of Serbian CAH patients revealed two novel CYP21A2 mutations. This study will enable genetic counseling in our population and contribute to better understanding of molecular landscape of CAH in Europe.

Fetal endocrine therapy for congenital adrenal hyperplasia should not be done

Prenatal treatment of congenital adrenal hyperplasia by administering dexamethasone to a woman presumed to be carrying an at-risk fetus remains a controversial experimental treatment. Review of data from animal experimentation and human trials indicates that dexamethasone cannot be considered safe for the fetus. In animals, prenatal dexamethasone decreases birth weight, affects renal, pancreatic beta cell and brain development, increases anxiety and predisposes to adult hypertension and hyperglycemia. In human studies, prenatal dexamethasone is associated with orofacial clefts, decreased birth weight, poorer verbal working memory, and poorer self-perception of scholastic and social competence. Numerous medical societies have cautioned that prenatal treatment of adrenal hyperplasia with dexamethasone is not appropriate for routine clinical practice and should only be done in Institutional Review Board approved, prospective clinical research settings with written informed consent. The data indicate that this treatment is inconsistent with the classic medical ethical maxim to 'first do no harm'.

Human cytochrome P450 and personalized medicine

Personalized medicine has become a hot topic ascribed to the development of Human Genome Project. And currently, bioinformatics methodology plays an essential role in personal drug design. Here in this review we mainly focused on the basic introduction of the SNPs of human drug metabolic enzymes and their relationships with personalized medicine. Some common bioinformatics analysis methods and latest progresses and applications in personal drug design have also been discussed. Thus bioinformatics studies on SNPs of human CYP450 genes will contribute to indicate the most possible genes that are associated with human diseases and relevant therapeutic targets, identify and predict the drug efficacy and adverse drug response, investigate individual gene specific properties and then provide personalized and optimal clinic therapies.

A simple method for gene phasing using mate pair sequencing

BACKGROUND

Recessive genes cause disease when both copies are affected by mutant loci. Resolving the cis/trans relationship of variations has been an important problem both for researchers, and increasingly, clinicians. Of particular concern are patients who have two heterozygous disease-causing mutations and could be diagnosed as affected (one mutation on each allele) or as phenotypically normal (both mutations on the same allele). Several methods are currently used to phase genes, however due to cost, complexity and/or low sensitivity they are not suitable for clinical purposes.

METHODS

Long-range amplification was used to select and enrich the target gene (CYP21A2) followed by modified mate-pair sequencing. Fragments that mapped coincidently to two heterozygous sites were identified and used for statistical analysis.

RESULTS

Probabilities for cis/trans relationships between heterozygous positions were calculated along with 99% confidence intervals over the entire length of our 10 kb amplicons. The quality of phasing was closely related to the depth of coverage and the number of erroneous reads. Most of the error was found to have been introduced by recombination in the PCR reaction.

CONCLUSIONS

We have developed a simple method utilizing massively parallel sequencing that is capable of resolving two alleles containing multiple heterozygous positions. This method stands out among other phasing tools because it provides quantitative results allowing confident haplotype calls.

Molecular analysis of the CYP21A2 gene in Chinese patients with steroid 21-hydroxylase deficiency

OBJECTIVE

21-Hydroxylase deficiency (21-OHD) is the most common cause of congenital adrenal hyperplasia (CAH), a family of autosomal recessive disorders involving impaired cortisol synthesis. This study aimed to design a reliable and rational approach for identifying mutations in the CYP21A2 gene and to characterize the molecular basis of 21-OHD in 30 Chinese patients.

DESIGN AND METHODS

Copy number variations were investigated by multiplex ligation-dependent probe amplification (MLPA). Locus-specific polymerase chain reaction (PCR)/restriction endonuclease analysis was then used to verify CYP21A2 rearrangement products and prevent allele dropout. Direct sequencing of rearrangement products was performed to further refine recombination breakpoint locations. Direct sequencing of the entire CYP21A2 gene was used to detect microconversions.

RESULTS

We successfully characterized 60 CYP21A2 alleles from 30 patients with genetic defects. The most common one was intron 2 splice mutation (38.3%). Eighteen alleles with large gene deletions/conversions were identified, which accounted for nearly one-third (30.0%) of the genetic defects. Among these, three types of CYP21A1P/CYP21A2 chimeric genes (CH-1, CH-2, and CH-4) were characterized. Two novel CYP21A2 rearrangement genes were revealed and further demonstrated to be located downstream of the TNXB gene.

CONCLUSIONS

Our results indicate that the stepwise diagnostic procedure involving MLPA analysis, locus-specific PCR/restriction endonuclease analysis, and direct DNA sequencing can provide detailed genetic information about Chinese 21-OHD patients, which is helpful for characterizing structural rearrangements of CYP21A2.

Intraspecific evolution of human RCCX copy number variation traced by haplotypes of the CYP21A2 gene

The RCCX region is a complex, multiallelic, tandem copy number variation (CNV). Two complete genes, complement component 4 (C4) and steroid 21-hydroxylase (CYP21A2, formerly CYP21B), reside in its variable region. RCCX is prone to nonallelic homologous recombination (NAHR) such as unequal crossover, generating duplications and deletions of RCCX modules, and gene conversion. A series of allele-specific long-range polymerase chain reaction coupled to the whole-gene sequencing of CYP21A2 was developed for molecular haplotyping. By means of the developed techniques, 35 different kinds of CYP21A2 haplotype variant were experimentally determined from 112 unrelated European subjects. The number of the resolved CYP21A2 haplotype variants was increased to 61 by bioinformatic haplotype reconstruction. The CYP21A2 haplotype variants could be assigned to the haplotypic RCCX CNV structures (the copy number of RCCX modules) in most cases. The genealogy network constructed from the CYP21A2 haplotype variants delineated the origin of RCCX structures. The different RCCX structures were located in tight groups. The minority of groups with identical RCCX structure occurred once in the network, implying monophyletic origin, but the majority of groups occurred several times and in different locations, indicating polyphyletic origin. The monophyletic groups were often created by single unequal crossover, whereas recurrent unequal crossover events generated some of the polyphyletic groups. As a result of recurrent NAHR events, more CYP21A2 haplotype variants with different allele patterns belonged to the same RCCX structure. The intraspecific evolution of RCCX CNV described here has provided a reasonable expectation for that of complex, multiallelic, tandem CNVs in humans.

Mutational characterization of congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Malaysia

BACKGROUND AND AIM

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder. Our objective was to identify the 21-hydroxylase active gene, CYP21A2 mutations in Malaysian 21-OHD patients using different techniques.

MATERIALS AND METHODS

Blood samples were obtained from 97 Malaysian 21-OHD patients, which included 40 siblings from 19 families. We used various techniques which include restriction enzyme digestion, Southern blot, multiple ligation-dependent probe amplification (MLPA) and sequencing to elucidate CYP21A2 mutations.

RESULTS

Homozygous and compound heterozygous mutations were identified in 95 of the 97 patients (98%). Deletions of CYP21A2 were found in 43 patients (44.3%). Deletions identified in CYP21A2 gene were the usual 30-kb deletion comprising 3'UTR CYP21A1P, C4B and 5'CYP21A2, complete deletion of CYP21A2 gene, deletion in exons 1-3, exons 1-6 and exons 1-8 of CYP21A2. The common mutations identified in CYP21A2 gene were deletion/conversion (22.6%), p.R356W (22%), IVS2-13A/C>G (21.3%), p.I172N (5.3%), p.Q318X (5.3%), and p.P30L (1.03%). This is the first report of the mutation frequency in CYP21A2 gene among the Malay ethnic group. Two novel mutations, c.Y97insT and p.L345P were identified in our patients. Our results show good phenotype-genotype correlation in most of the cases, although clinical variations were identified in some patients.

CONCLUSIONS

The study has found various mutations including deletions in CYP21A2 gene in Malaysian patients with 21-hydroxylase deficiency using the MLPA technique that is being widely used in present laboratory settings.

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.

Management of CAH during pregnancy: optimizing outcomes

PURPOSE OF REVIEW

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is one of the most common autosomal recessive disorders. In the past, pregnancy was considered to be unlikely for women with CAH, particularly the classical forms. The purpose of this review is to provide current information regarding the pathophysiology of CAH, factors relevant for female and male fertility, and recommendations for management during pregnancy.

RECENT FINDINGS

Individuals with CAH, both female and male, have reduced fertility. For women, chronic anovulation, elevated progestin levels, and aberrant endometrial implantation have been identified as reasons for the subfertility. Testicular adrenal rest tumors, oligospermia, and hypogonadotropic hypogonadism are frequently associated with subfertility in men with all forms of CAH.

SUMMARY

Adequate suppression of progesterone appears to be an essential aspect of preconception management for women. Most importantly, treatment needs to be individualized. Awareness of these factors and appropriate therapeutic interventions can lead to successful outcome defined as a healthy live born infant.

Reverse-hybridization assay for rapid detection of common CYP21A2 mutations in dried blood spots from newborns with elevated 17-OH progesterone

BACKGROUND

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder most commonly caused by defects in the CYP21A2 gene. Neonatal CAH-screening based on 17-hydroxyprogesterone (17-OHP) measurements prevents life-threatening salt wasting conditions in newborns, but results in a considerable false-positive rate. Therefore, efficient second tier tests are required.

METHODS

We developed a reverse-hybridization test strip-based assay (CAH StripAssay) covering the most prevalent CYP21A2 point mutations/small insertions/deletions occurring in Middle European populations. Assay specificity was validated using plasmid clones, and wild-type and mutant reference DNAs. Its practicability was evaluated in 271 samples from patients with CAH, suspected CAH, and dried blood spots from screening-positive newborns.

RESULTS

All eleven point mutations and 51% of large deletions/conversions could be unambiguously identified when compared to reference methods (DNA sequencing, MLPA). After exclusion of rare mutations (6.4%) not covered by the StripAssay, the overall detection rate was 85%. Undetected heterozygous deletions/conversions caused a lack of information, but did not result in an incorrect prediction of phenotypes.

CONCLUSIONS

Our novel CAH StripAssay proved to be a fast (7h) and reliable method for detection of common CYP21A2 mutations. Implemented as a second-tier test in CAH newborn screening, it has the potential to significantly reduce recall rates.

Nonclassic congenital adrenal hyperplasia

PURPOSE OF REVIEW

Late-onset or nonclassic congenital adrenal hyperplasia (NCAH) due to 21-hydroxylase deficiency is one of the most common autosomal recessive disorders. Reported prevalence ranges from 1 in 30 to 1 in 1000. Affected individuals typically present due to signs and symptoms of androgen excess. The purpose of this review is to provide current information regarding the pathophysiology, molecular genetics, and management of this common disorder.

RECENT FINDINGS

Subfertility and the consequences of elevated progesterone concentrations have been increasingly documented for women with NCAH. Although testicular adrenal rest tumors (TARTs) are more common in men with classical congenital adrenal hyperplasia, oligospermia and TARTs have been described in men with NCAH. The phenotypic spectrum of defects in other components of the steroidogenic pathway such as P450 oxidoreductase and steroidogenic acute regulatory protein has been expanded to include milder forms.

SUMMARY

Treatment needs to be directed toward the symptoms. Goals of treatment include normal linear growth velocity, normal rate of skeletal maturation, 'on-time' puberty, regular menstrual cycles, prevention of or limited progression of hirsutism and acne, and fertility. Treatment needs to be individualized and should not be initiated merely to decrease abnormally elevated hormone concentrations.

p.H282N and p.Y191H: 2 novel CYP21A2 mutations in Italian congenital adrenal hyperplasia patients

More than 90% of all cases of congenital adrenal hyperplasia (CAH) result from steroid 21-hydroxylase gene (CYP21A2) mutations. The CYP21A2 gene is located in the human leukocyte antigen (HLA) class III region on the short arm of chromosome 6p21.3, along with an inactive pseudogene, CYP21A1P, that is 98% homologous in its coding sequence with CYP21A2. Most CYP21A2 mutations result from intergenic recombinations between CYP21A2 and the closely linked CYP21A1P pseudogene. Rare mutations not generated by gene conversion account for only 5% to 10% of 21-hydroxylase deficiency alleles. However, detection of these rare and spontaneous mutations has continued to expand worldwide. We identified 2 novel CYP21A2 missense mutations (p.H282N and p.Y191H) in 2 Italian patients with simple-virilizing and nonclassic CAH forms. Functional analysis of these CYP21A2 mutations was performed. Functional in vitro assay for mutagenized CYP21A2 enzymes was performed in transiently transfected mammalian cells to test the residual enzyme activity and the apparent kinetic values. The residual activities obtained allowed us to classify the p.H282N and p.Y191H variants as simple-virilizing and nonclassic CAH associated mutations, respectively. These results correlate with the rate of severity of the patients' disease. This finding provides a further contribution for assisting in the diagnosis of CAH patients.

Three-dimensional structure of steroid 21-hydroxylase (cytochrome P450 21A2) with two substrates reveals locations of disease-associated variants

Steroid 21-hydroxylase (cytochrome P450 21A2, CYP21A2) deficiency accounts for ∼95% of individuals with congenital adrenal hyperplasia, a common autosomal recessive metabolic disorder of adrenal steroidogenesis. The effects of amino acid mutations on CYP21A2 activity lead to impairment of the synthesis of cortisol and aldosterone and the excessive production of androgens. In order to understand the structural and molecular basis of this group of diseases, the bovine CYP21A2 crystal structure complexed with the substrate 17-hydroxyprogesterone (17OHP) was determined to 3.0 Å resolution. An intriguing result from this structure is that there are two molecules of 17OHP bound to the enzyme, the distal one being located at the entrance of the substrate access channel and the proximal one bound in the active site. The substrate binding features locate the key substrate recognition residues not only around the heme but also along the substrate access channel. In addition, orientation of the skeleton of the proximal molecule is toward the interior of the enzyme away from the substrate access channel. The 17OHP complex of CYP21A2 provides a good relationship between the crystal structure, clinical data, and genetic mutants documented in the literature, thereby enhancing our understanding of congenital adrenal hyperplasia. In addition, the location of certain CYP21A2 mutations provides general understanding of structure/function relationships in P450s.

Molecular diagnosis of two families with classic congenital adrenal hyperplasia

We investigated the genetic defects in two families with classic congenital adrenal hyperplasia (CAH). Clinical data and vein blood of the family members were collected, hormonal evaluation, karyotype analysis, ultrasound and CT scans were performed, and a direct-sequencing of PCR products of the candidate genes was used to identify the mutations. In family A, Patients A-II:1 and A-II:2 were found to be in a compound heterozygous state for mutations of p.I172N (g.1004T>A) in exon 4 and IVS2-13A/C>G (g.659A/C>G) in intron 2 in CYP21A2 gene, their father A-I:1 and mother A-I:2 were found to carry a heterozygous mutation of IVS2-13A/C>G (g.659A/C>G) and p.I172N (g.1004T>A) respectively. In family B, Patient B-II:1 was detected to carry only one heterozygous mutation of p.I172N; no other mutations in CYP11B1, CYP17A1 or HSD3B2 genes were detected. Her father B-I:1 carried a heterozygous mutation of p.I172N (g.1004T>A) and her mother B-I:2 was found to be a wild type in all the candidate genes. Obviously, patients A-II:1 and A-II:2 inherited the p.I172N (g.1004T>A)-bearing maternal allele and the IVS2-13A/C>G (g.659A/C>G)-bearing paternal allele. And this kind of compound heterozygous mutations caused simple virilising (SV) CAH. While patient B-II:1, whose phenotype was SV CAH too, was found to carry only one heterozygous mutation of the p.I172N (g.1004T>A)-bearing paternal allele, and needed further studies.

Cushing's disease in a patient with steroid 21-hydroxylase deficiency

Cushing's disease rarely appears as a consequence of hereditary disease. However, familial diseases with diminished glucocorticoid feedback are associated with secondary hypercorticotropinism and have been shown to give rise to pituitary adenomas. We here describe the rare case of a 30-year old female patient with congenital adrenal hyperplasia who also showed clinical signs and a typical history of hypercortisolism that was specified as Cushing's disease. After removal of a pituitary microadenoma, serum-cortisol levels fell below normal and the symptoms improved. However, after four years the menstrual cycle was irregular again and ACTH levels were in the upper range of normal. A corticotropin challenge showed a minor cortisol response but a marked increase in 17-hydroxyprogesterone serum concentrations. Genetic analysis revealed a homozygous mutation in exon 7 of the CYP21A2 gene (CTG>TTG, p.V281L). We conclude that a marked ACTH drive was able to override insufficient 21-hydroxylation and even to cause hypercortisolism. Although we describe a rare case, the impairment of the glucocorticoid feedback system in the context of congenital adrenal hyperplasia and other diseases may contribute to the development of secondary hypercorticotropinism as well as corticotropin producing adenomas.