Molecular analysis of CYP21A2 can optimize the follow-up of positive results in newborn screening for congenital adrenal hyperplasia

Mutation distributions among patients with congenital adrenal hyperplasia from five regions of Brazil: a systematic review

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is an autosomal recessive disorder caused by CYP21A2 gene mutations, and its molecular diagnosis is widely used in clinical practice to confirm the hormonal diagnosis. Hence, considering the miscegenation of the Brazilian population, it is important to determine a mutations panel to optimise the molecular diagnosis. The objective was to review the CYP21A2 mutations' distribution among Brazilian regions. Two reviewers screened Brazilian papers up to February 2020 in five databases. The pair-wise comparison test and Holm method were used in the statistical analysis. Nine studies were selected, comprising 769 patients from all regions. Low proportion of males and salt-wasters was identified in the North and Northeast regions, although without significant difference. Large gene rearrangements also had a low frequency, except in the Center-West and South regions (p < 0.05). The most frequent mutations were p.I172N, IVS2-13A/C>G, p.V281L and p.Q318X, and significant differences in their distributions were found: p.V281L was more frequent in the Southeast and p.Q318X in the Center-West and Northeast regions (p < 0.05). Thirteen new mutations were identified in 3.8%-15.2% of alleles, being more prevalent in the North region, and six mutations presented a founder effect gene. Genotype-phenotype correlation varied from 75.9%-97.3% among regions. The low prevalence of the salt-wasting form, affected males and severe mutations in some regions indicated pitfalls in the clinical diagnosis. The good genotype-phenotype correlation confirms the usefulness of molecular diagnosis; however, the Brazilian population also presents significant prevalence of novel mutations, which should be considered for a molecular panel.

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

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

Congenital Adrenal Hyperplasia-Current Insights in Pathophysiology, Diagnostics, and Management

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders affecting cortisol biosynthesis. Reduced activity of an enzyme required for cortisol production leads to chronic overstimulation of the adrenal cortex and accumulation of precursors proximal to the blocked enzymatic step. The most common form of CAH is caused by steroid 21-hydroxylase deficiency due to mutations in CYP21A2. Since the last publication summarizing CAH in Endocrine Reviews in 2000, there have been numerous new developments. These include more detailed understanding of steroidogenic pathways, refinements in neonatal screening, improved diagnostic measurements utilizing chromatography and mass spectrometry coupled with steroid profiling, and improved genotyping methods. Clinical trials of alternative medications and modes of delivery have been recently completed or are under way. Genetic and cell-based treatments are being explored. A large body of data concerning long-term outcomes in patients affected by CAH, including psychosexual well-being, has been enhanced by the establishment of disease registries. This review provides the reader with current insights in CAH with special attention to these new developments.

Characterization of Mutations Causing CYP21A2 Deficiency in Brazilian and Portuguese Populations

Deficiency of 21-hydroxylase enzyme (CYP21A2) represents 90% of cases in congenital adrenal hyperplasia (CAH), an autosomal recessive disease caused by defects in cortisol biosynthesis. Computational prediction and functional studies are often the only way to classify variants to understand the links to disease-causing effects. Here we investigated the pathogenicity of uncharacterized variants in the CYP21A2 gene reported in Brazilian and Portuguese populations. Physicochemical alterations, residue conservation, and effect on protein structure were accessed by computational analysis. The enzymatic performance was obtained by functional assay with the wild-type and mutant CYP21A2 proteins expressed in HEK293 cells. Computational analysis showed that p.W202R, p.E352V, and p.R484L have severely impaired the protein structure, while p.P35L, p.L199P, and p.P433L have moderate effects. The p.W202R, p.E352V, p.P433L, and p.R484L variants showed residual 21OH activity consistent with the simple virilizing phenotype. The p.P35L and p.L199P variants showed partial 21OH efficiency associated with the non-classical phenotype. Additionally, p.W202R, p.E352V, and p.R484L also modified the protein expression level. We have determined how the selected CYP21A2 gene mutations affect the 21OH activity through structural and activity alteration contributing to the future diagnosis and management of CYP21A2 deficiency.

Reassessment of predictive values of ACTH-stimulated serum 21-deoxycortisol and 17-hydroxyprogesterone to identify CYP21A2 heterozygote carriers and nonclassic subjects

INTRODUCTION

Heterozygotes (HZs) for 21-hydroxylase deficiency (21OHD) are highly prevalent, ranging from 1:60 to 1:11 for classic and nonclassic (NC) forms, respectively. Detection of HZ and asymptomatic NC by CYP21A2 genotyping is valuable for genetic counselling, but costly, complex and narrowly available. Adrenocorticotropic hormone (ACTH)-stimulated serum 17-hydroxyprogesterone (17P) and 21-deoxycortisol (21DF) discriminate 21OHD phenotypes effectively, notably if measured simultaneously by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

OBJECTIVE

This study was performed to reassess former LC-MS/MS-defined post-ACTH 21DF, 17P and cortisol (F) cutoffs in family members at risk for 21OHD.

DESIGN AND PATIENTS

Prospective study in which we screened 58 asymptomatic relatives from families with 21OHD patients and compared post-ACTH steroid phenotypes with subsequent genotypes.

RESULTS

Post-ACTH 21DF, 17P, F and (21DF + 17P)/F ratio segregate NC, HZ and wild-type (WT) phenotypes (subsequently genotyped) with some overlap. New receiver operating characteristic curve-defined cutoffs for post-ACTH 21DF, 17P and (21DF + 17P)/F ratio are 60 ng/dl, 310 ng/dl and 12 (unitless). Twenty-six of 33 HZ and all 6 NC (82.1%) had post-ACTH 21DF > 60 and 17P > 310 ng/dl, whereas 17/19 WT (89.5%) had values below cutoffs. Post-ACTH 21DF and 17P had a strong positive correlation (r = .9558; p < .001). A (21DF + 17P)/F ratio > 12 correctly identified 36 of 39 HZ plus NC (92.3% sensitivity) with 84.2% specificity (16 of 19 WT). Given the high frequency of 21OHD HZ, the negative prediction of ratio values below 12 excludes heterozygosity in 99.8% and 99.1% for classic and NC mutations, respectively.

CONCLUSIONS

Reassessed ACTH-stimulated 21DF and 17P cutoffs by LC-MS/MS (60 and 310 ng/dl, respectively) correctly recognised 82.5% HZ plus NC, but combined precursor-to-product ratio ([21DF + 17P]/F) cutoff of 12 was superior, identifying 92.3% HZ plus NC. Since one WT subject is an outlier (potential HZ), these values would be somewhat better reinforcing their utility for screening asymptomatic relatives at risk for 21OHD.

Outcome of Newborn Screening for Congenital Adrenal Hyperplasia at Two Time Points

BACKGROUND/AIMS

Screening newborns for congenital adrenal hyperplasia (CAH) is problematic owing to the dynamic changes in serum 17-hydroxyprogesterone (17-OHP) levels following birth. Our study objectives were to determine the accuracy of screening, severity of CAH, and biochemical and clinical outcomes of cases detected by our program which collects specimens at 2 time periods following birth.

METHODS

We reviewed all CAH cases detected in the Northwest Regional Newborn Screening Program from 2003 through 2017. Comparison was made of screening and confirmatory serum 17-OHP, neonatal, maternal, and follow-up auxologic data, steroid treatment doses, and 21-hydroxylase genotype in cases detected on the first versus second test.

RESULTS

Out of 164 cases of CAH, 25% were detected on the second screen. Infants detected on the second test had a lower screening 17-OHP (147 vs. 294 ng/mL), lower confirmatory serum 17-OHP (7,772 vs. 14,622 ng/dL), and were more likely to have simple virilizing CAH. There were no identifiable neonatal or maternal factors associated with detection on the second test. 21-Hydroxylase genotypes overlapped in first versus second screen cases.

CONCLUSION

Early collection of specimens necessitated by early discharge resulted in milder CAH cases falling below the screening 17-OHP cutoff. In our program 25% of cases were detected on a routine second screen.

Molecular Analysis of 21-Hydroxylase Deficiency Reveals Two Novel Severe Genotypes in Affected Newborns

BACKGROUND AND OBJECTIVE

Congenital adrenal hyperplasia involves a series of autosomal recessive disorders where adrenal steroidogenesis is affected. We present a detailed molecular investigation of 13 newborns affected from the severe form of congenital adrenal hyperplasia related to 21-hydroxylase deficiency.

METHODS

All patients were diagnosed with classical congenital adrenal hyperplasia in the neonatal period due to adrenal crisis and/or ambiguous genitalia presentation. None of the infants was identified through a congenital adrenal hyperplasia newborn screening program. A molecular analysis of the CYP21A2 gene and a familiar segregation analysis were performed.

RESULTS

Adrenal crisis was the most severe manifestation in the male salt-wasting newborns while all female patients presented with atypical genitalia. Newborns were correctly genotyped and no genotype-phenotype divergences were found. Two novel severe genotypes, not previously reported, were identified. The novel CYP21A2 frameshift mutations (c.793delG and c.297dupG) were added to the other 45 variants recently reported in the literature, leading to a total count of 279 pathogenic variants affecting the gene.

CONCLUSIONS

We have successfully genotyped 13 infants diagnosed with classical congenital adrenal hyperplasia after birth. Our molecular approach led to the identification of two novel frameshift CYP21A2 pathogenic variants related to the salt-wasting form of congenital adrenal hyperplasia.

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

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

High frequency of non-classical congenital adrenal hyperplasia form among children with persistently elevated levels of 17-hydroxyprogesterone after newborn screening

Background Early diagnosis after newborn screening (NBS) for congenital adrenal hyperplasia (CAH) allows proper treatment, reducing mortality rates and preventing development of hyperandrogenic manifestations and incorrect sex assignment at birth. Despite the high NBS sensitivity to detect CAH classical forms, one of the main issues is identifying asymptomatic children who remained with increased 17-hydroxyprogesterone (17-OHP) levels. In this study, we aimed to contribute to understanding the diagnosis of these children. Methods Children with increased serum 17-OHP levels, and without disease-related clinical features during follow-up, underwent the entire CYP21A2 gene sequencing and multiplex ligation-dependent probe amplification (MLPA) analysis (SALSA MLPA P050B CAH). Patients' genotypes were subsequently sorted as compatible with CAH disease, and children were evaluated to determine the clinical status. Results During the study period, 106,476 newborns underwent CAH NBS. During follow-up, 328 children (0.3%) were identified as having false-positive tests and 295 were discharged after presenting with 17-OHP levels within reference values. Thirty-three remained asymptomatic and with increased serum 17-OHP levels after a mean follow-up of 3.4 years, and were subjected to molecular analysis. Seventeen out of the 33 children carried mutations: seven in the heterozygous state, nine carried non-classical genotypes and the remaining child carried a classical genotype. Conclusions We found a high frequency of non-classical CAH (NCCAH) diagnosis among children with persistent elevation of 17-OHP levels. Our findings support molecular study as decisive for elucidating diagnosis in these asymptomatic children. Molecular analysis as a confirmatory test is relevant to guide their follow-up, allows genetic counseling and avoids over treating NCCAH form.

Clinical and molecular profile of newborns with confirmed or suspicious congenital adrenal hyperplasia detected after a public screening program implementation

OBJECTIVE

To describe the results obtained in a neonatal screening program after its implementation and to assess the clinical and molecular profiles of confirmed and suspicious congenital adrenal hyperplasia cases.

METHODS

A cross-sectional study was conducted. Newborns with suspected disease due to high 17-hydroxyprogesterone levels and adjusted for birth weight were selected. Classical congenital adrenal hyperplasia (salt-wasting and simple virilizing forms) was diagnosed by an increase in 17-hydroxyprogesterone levels as confirmed in the retest, clinical evaluation, and genotype determined by SNaPshot and multiplex ligation-dependent probe amplification.

RESULTS

After 24 months, 15 classic congenital adrenal hyperplasia cases were diagnosed in a total of 217,965 newborns, with an estimated incidence of 1:14,531. From 132 patients, seven non-classical and 14 heterozygous patients were screened for CYP21A2 mutations, and 96 patients presented false positives with wild type CYP21A2. On retest, increased 17-hydroxyprogesterone levels were found in classical congenital adrenal hyperplasia patients and showed significant correlation with genotype-related classical genital adrenal hyperplasia. The most frequent mutations were IVS2-13A/C>G followed by gene deletion or rearrangement events in the classical form. In non-classical and heterozygous diseases, p.Val282Leu was the most common mutation.

CONCLUSIONS

The results underscore the effectiveness of congenital adrenal hyperplasia neonatal screening in the public health system and indicate that the adopted strategy was appropriate. The second sample collection along with genotyping of suspected cases helped to properly diagnose both severe and milder cases and delineate them from false positive patients.

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.

Steroidogenesis: Unanswered Questions

Until the mid-1980s studies of steroidogenesis largely depended on identifying steroid structures and measuring steroid concentrations in body fluids. The molecular biology revolution radically revolutionized studies of steroidogenesis with the cloning of known steroidogenic enzymes, by identifying novel factors, and delineating the genetic basis of known and newly discovered diseases. Unfortunately, this dramatic success has led many young research-oriented endocrinologists to regard steroidogenesis as a 'solved area'. However, many important and exciting questions remain, especially concerning the mechanisms of cholesterol delivery to the steroidogenic machinery, the biochemistry of androgen synthesis, the regulation and biological role of adrenarche, fetal adrenal development and involution, the roles of steroids made in 'extraglandular' cells, and the search for genetic disorders. This review outlines some of these questions, but this list is necessarily incomplete.

Hypertension in children with congenital adrenal hyperplasia

OBJECTIVES

Estimates of high blood pressure (BP) incidence in children with congenital adrenal hyperplasia (CAH) vary widely; risk factors are poorly understood. We estimated incidence of hypertension by CAH subtype and sex, and assessed its association with body mass index, hydrocortisone and fludrocortisone.

DESIGN

Longitudinal.

PATIENTS

Chart review of 180 paediatric CAH patients (120 salt wasting; 60 simple virilizing; 93 females) seen from 1970 to 2013.

MEASUREMENTS

High BP was diagnosed by diastolic or systolic blood pressure measurement ≥95th percentile for age, sex and height; hypertension was diagnosed with high BP on at least three clinic visits.

RESULTS

Children with classic CAH who received fludrocortisone had a significantly higher rate of hypertension (55% vs 31%) than those who did not. Hypertension incidence was higher in salt-wasting CAH (58%) than in simple-virilizing CAH (35%). Hypertension first occurred before age 5 years in 91% of salt-wasting males and 50% of cases in salt-wasting females; most simple-virilizing cases occurred during ages 10-18 years. Rates of hypertension were higher in children who had three or more measurements with 17-OHP < 400 ng/dl (12·12 nmol/l), and this difference was significant in salt-wasting males. Children on fludrocortisone who had three or more readings of 17-OHP < 400 ng/dl (12·12 nmol/l) had a significantly higher rate of hypertension than those who did not. Hydrocortisone dose was not associated with hypertension.

CONCLUSION

Children with CAH are at higher risk for hypertension than the general paediatric population, and incidence differs by sex and CAH subtype. Hypertension was higher in children on fludrocortisone and who were oversuppressed.

Molecular CYP21A2 diagnosis in 480 Brazilian patients with congenital adrenal hyperplasia before newborn screening introduction

BACKGROUND

Most congenital adrenal hyperplasia (CAH) patients carry CYP21A2 mutations derived from conversion events involving the pseudogene, and the remaining carry new mutations.

OBJECTIVE

To review causal mutations and genotype-phenotype correlation in 480 Brazilian patients.

METHODS

DNA was extracted from 158 salt-wasters (SWs), 116 simple virilizing (SV), and 206 nonclassical (NC) patients. Fourteen point mutations were screened by allele-specific PCR, large rearrangements by Southern blotting/MLPA, and sequencing was performed in those with incomplete genotype. The gene founder effect was analyzed by microsatellite studies. Patients were divided into six genotypes (Null; A: <2%; B: 3-7%; C: >20% of residual enzymatic activity (EA); D: unknown EA; E: incomplete genotype).

RESULTS

Targeted methodologies defined genotype in 87.6% of classical and in 80% of NC patients and the addition of sequencing in 100 and 83.5%, respectively. The most frequent mutations were p.V281L (26.6% of alleles), IVS2-13A/C>G (21.1%), and p.I172N (7.5%); seven rare mutations and one novel mutation (p.E351V) were identified. Gene founder effect was observed in all but one (p.W19X) mutation. Null, A, B, and C genotypes correlated with SW (88%), SW (70%), SV (98%), and NC forms (100%), respectively. In group D, the p.E351V mutation correlated with classical form and group E comprised exclusively NC-patients. ACTH-stimulated 17OHP level of 44.3ng/mL was the best cutoff to identify NC-patients carrying severe mutations.

CONCLUSIONS

We identified a good genotype-phenotype correlation in CAH, providing useful data regarding prediction of disease's severity; moreover, we suggest that ACTH-stimulated 17OHP levels could predict carrier status for severe mutations. Sequencing is essential to optimize molecular diagnosis in Brazilian CAH patients.

Disorders of sex development: effect of molecular diagnostics

Disorders of sex development (DSDs) are a diverse group of conditions that can be challenging to diagnose accurately using standard phenotypic and biochemical approaches. Obtaining a specific diagnosis can be important for identifying potentially life-threatening associated disorders, as well as providing information to guide parents in deciding on the most appropriate management for their child. Within the past 5 years, advances in molecular methodologies have helped to identify several novel causes of DSDs; molecular tests to aid diagnosis and genetic counselling have now been adopted into clinical practice. Occasionally, genetic profiling of embryos prior to implantation as an adjunct to assisted reproduction, prenatal diagnosis of at-risk pregnancies and confirmatory testing of positive results found during newborn biochemical screening are performed. Of the available genetic tests, the candidate gene approach is the most popular. New high-throughput DNA analysis could enable a genetic diagnosis to be made when the aetiology is unknown or many differential diagnoses are possible. Nonetheless, concerns exist about the use of genetic tests. For instance, a diagnosis is not always possible even using new molecular approaches (which can be worrying for the parents) and incidental information obtained during the test might cause anxiety. Careful selection of the genetic test indicated for each condition remains important for good clinical practice. The purpose of this Review is to describe advances in molecular biological techniques for diagnosing DSDs.

A three-year follow-up of congenital adrenal hyperplasia newborn screening

OBJECTIVE

congenital adrenal hyperplasia (CAH) newborn screening can prevent neonatal mortality in children with the salt-wasting form of the disease and prevent incorrect gender assignments, which can occur in females. However, the occurrence of false-positive results in preterm or low-birth-weight newborns creates some diagnostic difficulties, with consequent therapeutic implications. This study aimed to report the results of a pilot project for neonatal CAH screening conducted in the state of Minas Gerais, Brazil from 09/2007 to 05/2008 with a three-year follow-up.

METHODS

dried blood specimens were collected on filter paper cards three to seven days after birth of all newborns in the period. Samples were analyzed for 17-hydroxyprogesterone using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

a total of 159,415 children were screened. The apparent incidence of the classic variant of the disease was 1:9,963, based on initial diagnoses following newborn screening. During the follow-up period, eight of 16 children initially diagnosed with CAH were reclassified as unaffected, resulting in a revised incidence of 1:19,927. The false-positive rate was 0.31%, and the positive predictive value was 2.1%. Sensitivity and specificity were 100% and 99.7%, respectively.

CONCLUSIONS

newborn screening is an important public health policy in developing countries such as Brazil, where CAH remains underdiagnosed. It has great potential to identify children with the disease who otherwise cannot be diagnosed earlier. Long-term follow-up and monitoring of all children with positive screening results are crucial to ensure a correct diagnosis and to calculate a reliable incidence ratio of the disease.

Obesity and familial predisposition are significant determining factors of an adverse metabolic profile in young patients with congenital adrenal hyperplasia

BACKGROUND/AIMS

Glucocorticoid (GC) therapy is known to predispose to an adverse metabolic profile. Therefore, we investigated the prevalence of obesity and metabolic syndrome (MetS) in young patients with congenital adrenal hyperplasia (CAH) and to correlate this prevalence with GC treatment and family history.

METHODS

The study population consisted of 33 young CAH patients who received cortisone acetate during their growth periods; those who were salt wasters also received fludrocortisone. Obesity was defined by a body mass index (BMI) >95th percentile and MetS by the National Cholesterol Education Program Third Adult Treatment Panel modified criteria. Each patient's familial history of MetS components was assessed. The impact of GC therapy on the metabolic profile was analyzed by comparing CAH patients with BMI z-score-matched controls.

RESULTS

MetS and obesity were observed in 12.1 and 30.3% of the CAH patients, respectively, both of which were higher than in the reference population. A positive family history of MetS was found to be more prevalent in the obese patients compared with the nonobese CAH patients, and similar findings were observed for the controls. The metabolic profile did not differ between the CAH patients and matched subjects.

CONCLUSION

CAH patients presented a higher prevalence of obesity and MetS, which were not correlated with the GC treatment. This study suggests that obesity and familial predisposition are significant determining factors for an adverse metabolic profile in CAH patients.

Influence of the A3669G Glucocorticoid Receptor Gene Polymorphism on the Metabolic Profile of Pediatric Patients with Congenital Adrenal Hyperplasia

Background. Pediatric CAH patients have an increased risk of cardiovascular disease, and it remains unknown if genetic predisposition is a contributing factor. Glucocorticoid receptor gene (NR3C1) polymorphisms are associated with an adverse metabolic profile. Our aim was to analyze the association between the NR3C1 polymorphisms and the metabolic profile of pediatric CAH patients. Methods. Forty-one patients (26SW/15SV) received glucocorticoid (GC) replacement therapy to achieve normal androgen levels. Obesity was defined by BMI ≥ 95th percentile. NR3C1 alleles were genotyped, and association analyses with phenotype were done with Chi-square, t-test, and multivariate and regression analysis. Results. Obesity was observed in 31.7% of patients and was not correlated with GC doses and treatment duration. Z-score BMI was positively correlated with blood pressure, triglycerides, LDL-c levels, and HOMA-IR. NR3C1 polymorphisms, BclI and A3669G, were found in 23.1% and 9.7% of alleles, respectively. A3669G carriers presented higher LDL-c levels compared to wild-type subjects. BclI-carriers and noncarriers did not differ. Conclusion. Our results suggest that A3669G-polymorphism could be involved with a susceptibility to adverse lipid profile in pediatric CAH patients. This study provides new insight into the GR screening during CAH treatment, which could help to identify the subgroup of at-risk patients who would most benefit from preventive therapeutic action.

Weight-adjusted neonatal 17OH-progesterone cutoff levels improve the efficiency of newborn screening for congenital adrenal hyperplasia

OBJECTIVE: To evaluate weight-adjusted strategy for levels of neonatal-17OHP in order to improve newborn screening (NBS) efficiency. SUBJECTS AND METHODS: Blood samples collected between 2-7 days of age from 67,640 newborns were evaluated. When N17OHP levels were > 20 ng/mL, and a second sample was requested. We retrospectively analyzed neonatal-17OHP levels measured by Auto DELFIA- B024-112 assay, grouped according to birth-weight: G1: < 1,500 g, G2: 1,501-2,000 g, G3: 2,000-2,500 g and G4: > 2,500 g. 17OHP cutoff values were determined for each group using the 97.5th, 99th, 99.5th and 99.8th percentiles. RESULTS: 0.5% of newborns presented false-positive results using the cutoff level > 20 ng/mL for all groups. Neonates of low birthweight made up 69% of this group. Seven full-term newborns presented congenital adrenal hyperplasia (CAH) and, except for one of them, 17OHP levels were > 120 ng/mL. Only the 99.8th percentile presented higher predictive positive value (2%), and lower rate of false-positives in all groups. CONCLUSIONS: We suggest the use of 99.8th percentile obtained by weight-adjusted N17OHP values of healthy newborns to reduce the rate of false-positive results in NBS.

Molecular testing in congenital adrenal hyperplasia due to 21α-hydroxylase deficiency in the era of newborn screening

Newborn screening (NBS) identifies the majority of classical [salt-wasting (SW) and simple-virilizing (SV)] cases of congenital adrenal hyperplasia (CAH) due to 21α-hydroxylase (21α-OHase) during the first days of life. Diagnosis of classical CAH is confirmed by follow-up serum 17-hydroxyprogesterone and/or the adrenocorticotropin stimulation test; however, neither test definitively distinguishes between the classical subtypes. After confirmation, all newborns are started on hydrocortisone (glucocorticoid) and fludrocortisone (mineralocorticoid) treatment. While initiating fludrocortisone treatment in classical CAH patients, independent of subtype and before SW signs or symptoms occur, prevents a life-threatening SW crisis, it may later complicate distinguishing between the classical subtypes. Genotype-phenotype correlations in 21α-OHase deficiency are excellent; however, molecular testing is not a regular part of the diagnostic workup. Molecular testing on 39 patients (25 identified by NBS) with an already established diagnosis of CAH identified 11 SW patients (8 identified by NBS) whose mutations suggested further biochemical and clinical reassessment of their subtype. Overall, SW accounted for 57.6% of our classical CAH patients, below the generally accepted figure that >75% of classical CAH are comprised of the SW form. In the era of NBS, molecular testing is a valuable supplemental tool identifying patients who may benefit from reassessment of their salt-retaining ability.