Estimation of the false-negative rate in newborn screening for congenital adrenal hyperplasia

Establishing 17-Hydroxyprogesterone Cutoff Values for Congenital Adrenal Hyperplasia in Preterm, Low Birth Weight, and Sick Newborns

BACKGROUND

Newborn screening for congenital adrenal hyperplasia (CAH) has benefits with a high adoption rate worldwide. It also has problems of high false positives, which can cause stress to the patient's family with economic losses and unnecessary visits of newborns to hospitals. Therefore, we investigated the influence of birth weight (BW), gestational age (GA), and GA with sampling time on 17-hydroxyprogesterone (17-OHP) concentration and attempted to establish the 17-OHP cutoff values in preterm, low birth weight (LBW), and sick newborns.

METHODS

Newborns (n=1,071) born between October 2020 and January 2022 were screened for CAH. Samples from neonates were collected on filter paper with the heel prick method. 17-OHP concentration was measured by time-resolved immunofluorescence with an AutoDELFIA Neonatal 17-hydroxyprogesteron kit and grouped in relation to BW, GA, and GA with sampling time.

RESULTS

The median age of newborns at neonatal sample collection was 6 days. 17-OHP concentration showed a statistically significant negative correlation with BW (r=-0.488, p<0.001) and GA (r=-0.560, p<0.001). Full-term and preterm subgroups had a similar decreasing tendency of 17-OHP concentration with increasing sampling time. Application of newly establishing cutoff criteria significantly reduced recall rates to 1.16%, 0.9%, and 1.75% according to each criterion of BW, GA, and GA with sampling time, respectively.

CONCLUSIONS

This study presents new 17-OHP cutoff values for preterm, LBW, and sick newborns. These data in our laboratory can be used as a reference by other laboratories for establishing new cutoff criteria to help lower the high recall rate and reduce unnecessary follow-up tests.

Adult height of children with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

BACKGROUND/PURPOSES

Congenital adrenal hyperplasia attributable to 21-hydroxylase deficiency (21-OHD) is a disorder of adrenal steroidogenesis. Achievement of optimal growth by such patients is challenging. We evaluated the adult height of Taiwanese children with 21-OHD and the effect of a gonadotropin-releasing hormone analogue (GnRHa) in patients with central precocious puberty (CPP) complicating 21-OHD.

METHODS

Among 116 patients with 21-OHD in Taiwan, 90 who had attained adult height were subjected to an analysis of height outcomes. Nine with progressive CPP were treated with GnRHa and the effects of this therapy on adult height were further analyzed.

RESULTS

In the pre-screening era, the percentage of boys with 21-OHD was lower than expected. Although neonatal screening can prevent mortality caused by adrenal crisis, some cases may be missed. The pooled mean adult height of the 78 patients treated with conventional therapy were -1.1 SD and -0.5 SD adjusting for the genetic potential. The disease features affecting height outcomes are the genetic height potential and in boys the simple virilizing type. Nine patients with CPP were treated with GnRHa in addition to conventional therapy; the mean adult height increased from the predicted -4.1 SD to -1.0 SD after 6.0 ± 2.5 years of treatment.

CONCLUSION

Patients with 21-OHD had poorer mean adult height. A high caregiver's index of suspicion is required for the early diagnosis of patients with 21-OHD missed on neonatal screening. Adjuvant therapy with GnRHa can improve the adult height of patients with CPP complicating 21-OHD.

Two girls with a neonatal screening-negative 21-hydroxylase deficiency requiring treatment with hydrocortisone for virilization in late childhood

Herein, we report two girls with a neonatal screening (NS)-negative 21-hydroxylase deficiency (21-OHD) requiring treatment with hydrocortisone due to virilization that developed in late childhood. Patient 1 was born prematurely on the 30th gestational week with normal external genitalia at birth. She passed the NS for 21-OHD. At 6 yr of age, she was referred to a hospital for evaluation of premature pubarche and clitoromegaly. Her diagnosis was central precocious puberty, and GnRH agonist was initiated. However, her symptoms did not improve despite treatment for over 4 years. She was then referred to our hospital where she was diagnosed with 21-OHD. Although she was started on hydrocortisone therapy, her adult height reached only 140 cm (−3.4 SD). Patient 2 was delivered at 37 weeks of gestation and passed the NS for 21-OHD. She was referred to a hospital because of premature pubarche at the age of 6 yr. She was diagnosed with 21-OHD, and hydrocortisone replacement therapy was initiated. Her present height at 13 yr of age is 148 cm (−1.3 SD). These cases reminded us that the possibility of 21-OHD should be considered when patients show premature pubarche or precocious puberty, even if they passed the NS test for 21-OHD.

The Cost-Effectiveness of Congenital Adrenal Hyperplasia Newborn Screening in Brazil: A Comparison Between Screened and Unscreened Cohorts

Background: Newborn screening for congenital adrenal hyperplasia (CAH-NBS) is not yet a worldwide consensus, in part due to inconclusive evidence regarding cost-effectiveness because the analysis requires an understanding of the short- and long-term costs of care associated with delayed diagnosis. Objective: The present study aimed to conduct a cost-effectiveness analysis (CEA) to compare the costs associated with CAH-NBS and clinical diagnosis. Methods: A decision model comparing the two strategies was tested by sensitivity analysis. The cost analysis perspective was the public health system. Unscreened patients' data were extracted from medical records of Hospital das Clinicas, Saõ Paulo, and screened data were extracted from the NBS Referral Center of São Paulo. The population comprised 195 classical patients with CAH, clinically diagnosed and confirmed by hormonal/CYP21A2 analysis, and 378,790 newborns screened during 2017. Adverse outcomes related to late diagnosis were measured in both cohorts, and the incremental cost-effectiveness ratio (ICER) was calculated. We hypothesized that CAH-NBS would be cost-effective. Results: Twenty-five screened infants were confirmed with CAH (incidence: 1:15,135). The mortality rate was estimated to be 11% in unscreened infants, and no deaths were reported in the screened cohort. Comparing the unscreened and screened cohorts, mean serum sodium levels were 121.2 mEq/L (118.3-124.1) and 131.8 mEq/L (129.3-134.5), mean ages at diagnosis were 38.8 and 17 days, and hospitalization occurred in 76% and 58% of the salt-wasting patients with the in the two cohorts, respectively. The NBS incremental cost was US$ 771,185.82 per death averted, which yielded an ICER of US$ 25,535.95 per discounted life-year saved. Conclusions: CAH-NBS is important in preventing CAH mortality/morbidity, can reduce costs associated with adverse outcomes, and appears cost-effective.

Newborn Screening for Congenital Adrenal Hyperplasia: Review of Factors Affecting Screening Accuracy

Newborn screening for 21-hydroxylase deficiency (21OHD), the most common form of congenital adrenal hyperplasia, has been performed routinely in the United States and other countries for over 20 years. Screening provides the opportunity for early detection and treatment of patients with 21OHD, preventing salt-wasting crisis during the first weeks of life. However, current first-tier screening methodologies lack specificity, leading to a large number of false positive cases, and adequate sensitivity to detect all cases of classic 21OHD that would benefit from treatment. This review summarizes the pathology of 21OHD and also the key stages of fetal hypothalamic-pituitary-adrenal axis development and adrenal steroidogenesis that contribute to limitations in screening accuracy. Factors leading to both false positive and false negative results are highlighted, along with specimen collection best practices used by laboratories in the United States and worldwide. This comprehensive review provides context and insight into the limitations of newborn screening for 21OHD for laboratorians, primary care physicians, and endocrinologists.

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.

Polycystic Ovary Syndrome and NC-CAH: Distinct Characteristics and Common Findings. A Systematic Review

Background: Twenty-one-hydroxylase-deficient non-classic adrenal hyperplasia (NC-CAH) is a very common autosomal recessive syndrome with prevalence between 1:1,000 and 1:2,000 individuals and the frequency varies according to ethnicity. On the other hand, polycystic ovary syndrome has a familial basis and it is inherited under a complex hereditary trait. This syndrome affects 6 to 10% of women in reproductive age and it is the most common endocrine disorder in young women. Our aim was to investigate, through a systematic review, the distinct characteristics and common findings of these syndromes. Methods: The search period covered January 1970 to November 2018, using the scientific databases PubMed. Inclusion criteria were adult women patients with PCOS or NC-CAH. Search terms were "polycystic ovary syndrome," "PCOS," "non-classical adrenal hyperplasia," "NC-CAH," "21-hydroxylase deficiency." From an initial 16,255 titles, the evaluations led to the final inclusion of 97 papers. Results: The clinical features of NC-CAH are hirsutism and ovulatory and menstrual dysfunction therefore; differentiation between these two syndromes is difficult based on clinical grounds only. Additionally, NC-CAH and PCOS are both associated with obesity, insulin resistance, and dyslipidaemia. Reproductive abnormalities are also common between these hyperandrogenemic disorders since in patients with NC-CAH polycystic ovarian morphology and subfertility are present as they are in women with PCOS. The diagnosis of PCOS, is confirmed once other disorders that mimic PCOS have been excluded e.g., conditions that are related to oligoovulation or anovulation and/or hyperandrogenism, such as hyperprolactinaemia, thyroid disorders, non-classic congenital adrenal hyperplasia, and androgen-producing neoplasms. Conclusions: The screening tool to distinguish non-classic adrenal hyperplasia from PCOS is the measurement of 17-hydroxyprogesterone levels. The basal levels of 17-hydroxyprogesterone may overlap, but ACTH stimulation testing can distinguish the two entities. In this review these two common endocrine disorders are discussed in an effort to unveil their commonalities and to illuminate their shadowed distinctive characteristics.

Development of CYP21A2 Genotyping Assay for the Diagnosis of Congenital Adrenal Hyperplasia

BACKGROUND

Steroid 21-hydroxylase deficiency due to CYP21A2 gene mutations represents more than 90% of all congenital adrenal hyperplasia cases. This deficiency is screened by measuring levels of 17-hydroxyprogesterone, which may vary, causing false positive or false negative results. In order to assist the diagnosis, molecular methodologies have been employed. This work aimed to perform genotyping assays to detect mutations in the CYP21A2 gene and compare the findings with other population studies.

METHODS

The SNaPshot assay was developed to simultaneously detect 12 frequent point mutations in the CYP21A2 gene (p.Arg409Cys, p.Gln319Ter, p.Arg357Trp, p.Leu308PhefsTer6, p.Val237Glu, IVS2-13A/C > G, p.Ile173Asn, p.Pro31Leu, p.Pro454Ser, p.Val282Leu, p.Gly111ValfsTer21 and p.His63Leu). The direct sequencing and multiplex ligation-dependent probe amplification assays were used to confirm point mutations present in the developed method. The latter was also used to search large deletions and gene conversion, complementing the investigation. A total of 166 cases were studied.

RESULTS

The SNaPshot assay was successfully developed to detect the 12 mutations. The results of mutation analysis indicated 84 pathogenic alleles in 48 cases, with p.Val282Leu (27.1%) and IVS2-13A/C > G (20.8%) being the most frequently found mutations. Between the findings of this study and those of other South American studies, there were significant differences in frequency for p.Pro31Leu and p.Val282Leu (p < 0.001). A new variant T in IVS2-13A/C > G was identified in two patients via the SNaPshot assay.

CONCLUSION

The molecular strategy developed for CYP21A2 gene mutation screening allowed us to detect the principle mutations described around the world. Furthermore, the first Southern Brazilian mutation frequencies concerning the CYP21A2 gene were obtained.

Effects of birth weight on profiles of dried blood amino-acids and acylcarnitines

Background

Birth weight influences profiles of dried blood amino-acids and acylcarnitines in newborn screening. This study aimed to define a more appropriate cut-off value to reduce the false positive rate and the number of recalled patients in newborn screening.

Methods

All babies who underwent newborn screening in our center were included; they were divided into groups by birth weight: 2500–3999 g (comparator group), <1000 g (group 1), 1000–1499 g (group 2), 1500–2499 g (group 3), and >4000 g (group 4). The 0.5th and 99.5th percentiles were used as the cut-off values. Comparisons were done on amino acid and acylcarnitines concentrations between the groups. False positive rate, positive predictive value, corrected false positive rate by birth weights were determined.

Results

Data on a total of 578,287 newborn infants were included in the analysis. The total false positive rate was 0.75%, and positive predictive value 2.89%. The false positive rate was 0.69%, 0.54% and 5.31% in infants with normal birth weight, birth weight of >4000 (group 4) and low birth weight of < 2500 g (groups 1, 2 and 3), respectively. Low-birth weight infants had much higher phenylalanine, tyrosine, methionine, arginine, propionylcarnitine, isovalerylcarnitine and octadecanoylcarnitine concentrations. Free carnitines and palmitoylcarnitine concentrations were lower. After adjusting for birth weight, false positive rate of all indices decreased to 0.53%, and positive predictive value increased to 4.31%.

Conclusions

Amino acid and carnitine concentrations in low-birth weight newborn infants may differ from the normal term newborn infants. The cut-off values of individual metabolites should be adjusted based on birth weight, to reduce false positive rate and increase positive predictive value.

Newborn screening for congenital adrenal hyperplasia in New York State

From 2007 to 2014 the New York State (NYS) Newborn Screening (NBS) program screened 2 million newborns for congenital adrenal hyperplasia (CAH). The data was analyzed to determine factors that affect 17α-hydroxyprogesterone levels and assist in developing algorithm changes that would improve the positive predictive value of the methodology being used. The concentration of 17-OHP in dried blood spots was measured using the AutoDELFIA Neonatal 17-OHP kit (Perkin Elmer, Turku, Finland). During the 8 year period of this study 2476 babies were referred, 105 babies were diagnosed with CAH (90 with the salt-wasting (SW), 8 with simple virilizing (SV), 5 with non-classical CAH, and 2 with another enzyme deficiency) and, 14 with possible CAH. Three false negative cases with SV-CAH were reported to the program. Of the total 108 known cases, 74 (69%) infants were detected by newborn screening in the absence of clinical information, or, known family history. The incidence of CAH in NYS is 1 in 18,170 with a ratio of SW to SV of 8.2:1. The incidence of CAH is lower in Black infants than in White, Hispanic and Asian infants. Despite a lower mean birth weight, female infants have a lower mean 17-OHP value than male infants and are under-represented in the referred category. As per other NBS programs the false positive rate is exacerbated by prematurity/low birth weight and by over-early specimen collection.

Guidelines for diagnosis and treatment of 21-hydroxylase deficiency (2014 revision)

Purpose of developing the guidelines: The first guidelines for diagnosis and treatment of 21-hydroxylase deficiency (21-OHD) were published as a diagnostic handbook in Japan in 1989, with a focus on patients with severe disease. The “Guidelines for Treatment of Congenital Adrenal Hyperplasia (21-Hydroxylase Deficiency) Found in Neonatal Mass Screening (1999 revision)” published in 1999 were revised to include 21-OHD patients with very mild or no clinical symptoms. Accumulation of cases and experience has subsequently improved diagnosis and treatment of the disease. Based on these findings, the Mass Screening Committee of the Japanese Society for Pediatric Endocrinology further revised the guidelines for diagnosis and treatment. Target disease/conditions: 21-hydroxylase deficiency. Users of the guidelines: Physician specialists in pediatric endocrinology, pediatric specialists, referring pediatric practitioners, general physicians; and patients.

Impact of hydrocortisone on adult height in congenital adrenal hyperplasia-the Minnesota cohort

OBJECTIVE

To estimate the impact of the average daily dose of hydrocortisone (HC) on the amount of growth attained in children with congenital adrenal hyperplasia (CAH). The effect of glucocorticoid therapy on adult height (AH) in children with CAH has yet to be elucidated.

STUDY DESIGN

Triple-logistic models estimating components of growth and maturation were fitted to longitudinal records of 104 patients with classic CAH from 3 pediatric medical centers in Minnesota between 1955 and 2012. A total of 3664 clinical encounters were examined. Random-effects longitudinal models with time-related covariates were used to estimate the effect of HC therapy on linear growth.

RESULTS

The predicted AH z-score (-0.7) was similar between the sexes and among CAH subtypes. The mean growth period HC dose was 18.9 ± 5.6 mg/m(2)/day. In the final regression model, HC dose was negatively associated with predicted AH, with each mg/m(2)/day increase in average growth period HC dose predicting a 0.37-cm decrease in AH (P < .004).

CONCLUSION

This study has quantified the fractional reduction in predicted final AH with an incremental increase in HC dose. These findings have important clinical implications in the decision making balance between HC replacement dose and adrenal androgen suppression in children with CAH.

Results from 28 years of newborn screening for congenital adrenal hyperplasia in sapporo

The primary goal of newborn mass screening (MS) for congenital adrenal hyperplasia (CAH) is the prevention of life-threatening salt-wasting crisis in the most severe forms of CAH, and MS for CAH has been implemented in several countries. We summarize here our experience and results from newborn CAH MS from 1982 to 2010 in Sapporo City. During these 28 yr, the level of 17-hydroxyprogesterone (17-OHP) was determined in MS of samples from 498,147 newborns. During this period, 26 individuals (19 females and 7 males) with 21-hydroxylase deficiency (21-OHD) were detected. Of the 26 CAH, 20 were classified as having the salt-wasting (SW) form, 4 were classified as having the simple virilizing (SV) form, and 2 were classified as having the noncalssic (NC) form. Therefore, the frequency of the classical type of CAH was 1 in 20,756. In order to improve the effectiveness, we employed high-performance liquid chromatography (HPLC) as a second tier test from 2000. During this period, among the recalled babies, 75.4% were born prior to the 37th wk of gestation age, and the recall rate was 5.38% for premature neonates and 0.06% for mature neonates. MS for CAH in Sapporo is effective for the identification of the SW and SV forms of 21-OHD. However, the recall rate of premature babies is still high after the introduction of HPLC as a second tier test.

Congenital adrenal hyperplasia and the second newborn screen

OBJECTIVE

To evaluate the effectiveness of a second newborn screen for congenital adrenal hyperplasia (CAH) in the state of Colorado and report characteristics associated with cases identified on the first versus second screen.

STUDY DESIGN

Colorado implemented newborn screening for CAH with 17-hydroxyprogesterone beginning August 2000. The first screening is performed within 72 hours of life and the second between 8 and 14 days of life. We compared infants diagnosed on the basis of the first versus second newborn screen.

RESULTS

The first screen identified 29 cases of which 28 represented classical CAH. The incidence of classical CAH on the first screen was 1:24,766. The second screen identified 17 additional cases, of which 11 represented classical CAH. Combined, the incidence of classical CAH was 1:17,789. The sensitivity of the first screen was 71.79%. The false negative rate of the first screen was 28.2%. In the absence of a second screen, 1:47,824 infants would have been missed. Infants diagnosed on the first screen had higher 17-hydroxyprogesterone values compared with those diagnosed on the second screen (P = .0008).

CONCLUSIONS

The use of a single newborn screen for CAH missed nearly 30% of classical CAH cases in Colorado. Addition of a second screen, therefore, can improve the operating characteristics of the newborn screening program.

Retention and research use of residual newborn screening bloodspots

The storage and use of residual newborn screening dried blood specimens has generated significant controversy in the past 5 years, primarily because of public concerns over the lack of parental knowledge and consent for these activities. State policies addressing the management of these specimens vary widely, and there is currently little guidance to aid new state policy development to address the concerns of program professionals, investigators, and the general public. This article offers guidance for state policy based on multiple sources of data, including public attitudes, professional statements, state experience, and an analysis of the ethical, social, legal, and biomedical issues from a multidisciplinary group of scholars. This guidance will be useful for state programs that seek to develop policies that are informed by a contemporary analysis of the key ethical, legal, and social aspects of this practice. This article represents the work of the authors and does not represent American Academy of Pediatrics policy.

The heritability of metabolic profiles in newborn twins

Identifying genetic and metabolic biomarkers in neonates has the potential to improve diagnosis and treatment of common complex neonatal diseases, and potentially lead to risk assessment and preventative measures for common adulthood illnesses such as diabetes and cardiovascular disease. There is a wealth of information on using fatty acid, amino acid and organic acid metabolite profiles to identify rare inherited congenital diseases through newborn screening, but little is known about these metabolic profiles in the context of the 'healthy' newborn. Recent studies have implicated many of the amino acid and fatty acid metabolites utilized in newborn screening in common complex adult diseases such as cardiovascular disease, insulin resistance and obesity. To determine the heritability of metabolic profiles in newborns, we examined 381 twin pairs obtained from the Iowa Neonatal Metabolic Screening Program. Heritability was estimated using multilevel mixed-effects linear regression adjusting for gestational age, gender, weight and age at time of sample collection. The highest heritability was for short-chain acylcarnitines, specifically C4 (h²=0.66, P=2 × 10⁻¹⁶), C4-DC (h²=0.83, P<10⁻¹⁶) and C5 (h²=0.61, P=1 × 10⁻⁹). Thyroid stimulating hormone (h²=0.58, P=2 × 10⁻⁵) and immunoreactive trypsinogen (h²=0.52, P=3 × 10⁻⁹) also have a strong genetic component. This is direct evidence for a strong genetic contribution to the metabolic profile at birth and that newborn screening data can be utilized for studying the genetic regulation of many clinically relevant metabolites.

Comparison of one-tier and two-tier newborn screening metrics for congenital adrenal hyperplasia

BACKGROUND

Newborn screening (NBS) for the classic forms of congenital adrenal hyperplasia (CAH) is mandated in all states in the United States. Compared with other NBS disorders, the false-positive rate (FPR) of CAH screening remains high and has not been significantly improved by adjusting 17α-hydroxyprogesterone cutoff values for birth weight and/or gestational age. Minnesota was the first state to initiate, and only 1 of 4 states currently performing, second-tier steroid profiling for CAH. False-negative rates (FNRs) for CAH are not well known.

METHODS

This is a population-based study of all Minnesota infants (769,834) born 1999-2009, grouped by screening protocol (one-tier with repeat screen, January 1999 to May 2004; two-tier with second-tier steroid profiling, June 2004 to December 2009). FPR, FNR, and positive predictive value (PPV) were calculated per infant, rather than per sample, and compared between protocols.

RESULTS

Overall, 15 false-negatives (4 salt-wasting, 11 simple-virilizing) and 45 true-positives were identified from 1999 to 2009. With two-tier screening, FNR was 32%, FPR increased to 0.065%, and PPV decreased to 8%, but these changes were not statistically significant. Second-tier steroid profiling obviated repeat screens of borderline results (355 per year average).

CONCLUSIONS

In comparing the 2 screening protocols, the FPR of CAH NBS remains high, the PPV remains low, and false-negatives occur more frequently than has been reported. Physicians should be cautioned that a negative NBS does not necessarily rule out classic CAH; therefore, any patient for whom there is clinical concern for CAH should receive immediate diagnostic testing.

Clinical and environmental influences on metabolic biomarkers collected for newborn screening

OBJECTIVES

Identifying common clinical and environmental factors that influence newborn metabolic biomarkers will improve the utilization of metabolite panels for clinical diagnostic medicine.

DESIGN AND METHODS

Environmental effects including gender, season of birth, gestational age, birth weight, feeding method and age at time of collection were evaluated for over 50 metabolites collected by the Iowa Neonatal Metabolic Screening Program on 221,788 newborns over a six year period.

RESULTS

We replicated well known observations that low birth weight and preterm infants have higher essential amino acids and lower medium and long chain acylcarnitine levels than their term counterparts. Smaller, but still significant, differences were observed for gender and timing of sample collection, specifically the season in which the infant was born. Most intriguing were our findings of higher thyroid stimulating hormone in the winter months (P<1×10(-40)) which correlated with an increased false positive rate of congenital hypothyroidism in the winter (0.9%) compared to summer (0.6%). Previous studies, conducted globally, have identified an increased prevalence of suspected and confirmed cases of congenital hypothyroidism in the winter months. We found that the percentage of unresolved suspected cases were slightly higher in the winter (0.3% vs. 0.2%).

CONCLUSIONS

We identified differences in metabolites by gestational age, birth weight, gender and season. Some are widely reported such as gestational age and birth weight, while others such as the effect of seasonality are not as well studied.

Genetic analysis of the CYP21A2 gene in neonatal dried blood spots from children with transiently elevated 17-hydroxyprogesterone

BACKGROUND

Neonatal screening for congenital adrenal hyperplasia (CAH) identifies a certain proportion of newborns with transient moderate elevation of 17-hydroxyprogesterone (17-OHP). These children require regular follow-up until normalization of their 17-OHP levels. We investigated the possibility of reducing the individuals' recall rates by using genetic methods on their original neonatal dried blood spots.

PATIENTS AND METHODS

We analysed neonatal dried blood spots from 753 subjects with transiently elevated levels of 17-OHP. The CYP21A2 gene was sequenced to detect point mutations, and the presence of CYP21A2 was further confirmed by two methods utilizing the difference between CYP21A2 and its CYP21A1P pseudogene in the sequence of exon 3 (8-bp deletion). The accuracy of the methods was verified using samples from 70 subjects with known CYP21A2 mutations and 181 healthy children.

RESULT

Among the 701 successfully sequenced samples from subjects with transiently elevated 17-OHP, 670 (95%) had no point mutations or novel variants in the CYP21A2 gene. We found no individuals carrying genotypes consistent with the diagnosis of CAH (i.e. homozygotes or compound heterozygotes for point mutations, large deletions or rearrangements). However, 21 heterozygous carriers of known point mutations that cause the classic and nonclassic forms of CAH were identified. Additionally, we detected eight heterozygous and two homozygous point variants with unknown functional significance.

CONCLUSION

Although CAH caused by 21-hydroxylase deficiency could be genetically excluded with a reasonable degree of confidence in 95% of the genotyped subjects that had transiently elevated 17-OHP, the performance of the tests was suboptimal when performed using dried blood spots and time-consuming in comparison with the current practice of repeated measurements of 17-OHP. The introduction of this method into clinical practice seems to be impractical at this stage.

Lessons learned from 5 years of newborn screening for congenital adrenal hyperplasia in the Czech Republic: 17-hydroxyprogesterone, genotypes, and screening performance

The aims were to summarize the experience and to determine the performance metrics of newborn screening (NBS) for congenital adrenal hyperplasia (CAH) in the Czech Republic. 17-Hydroxyprogesterone (17OHP) was measured in NBS samples prospectively in 545,026 newborns and retrospectively in 31 CAH patients born outside the study period. A total of 2,811 screened newborns had abnormal 17OHP; CAH was confirmed in 46 probands. One patient with a severe-moderate genotype of CAH had 17OHP below the cut-off and was diagnosed clinically. This corresponds to a screening sensitivity of 98% and a false positive rate (FPR) of 0.51%. The median of 17OHP in the most severe genotypes was 484 nmol/L (n = 21); in severe/moderate, 321 nmol/L (n = 30); in moderate, 61 nmol/L (n = 20); and in mild genotypes, 31 nmol/L (n = 7). NBS is efficient to detect severe CAH but may fail to detect milder variants. However, the FPR is too high but could be improved by application of a second tier test.

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.

Congenital adrenal hyperplasia: an update in children

PURPOSE OF REVIEW

Congenital adrenal hyperplasia (CAH) in children, the majority of which is due to 21-hydroxylase deficiency, represents a group of disorders in which there is impaired cortisol synthesis and abnormalities in adrenal hormonal profiles. There continues to be debate regarding the optimal management of and treatment for these children. This review will highlight the most recent advances in neonatal screening for CAH, as well as the timeliest recommendations for the treatment and management of 21-hydroxylase deficiency, both the classic and nonclassic forms of the disorder.

RECENT FINDINGS

Substantive advancements have been made with regard to neonatal screening for CAH, allowing for earlier diagnosis, while minimizing the morbidity and mortality associated with delayed detection. Although the achievement of normal growth and development remains the ultimate goal of treatment, recent studies have provided further insight into the management and refinement of therapy in these children.

SUMMARY

The optimal management and treatment for children with CAH is still unclear. Although there have been recent advances in the diagnosis and treatment of this group of disorders, there is still much to learn in order to optimize therapy for these individuals.

Genotype-phenotype correlation in CAH patients with severe CYP21A2 point mutations in the Republic of Macedonia

Steroid 21-hydroxylase deficiency is a most frequent cause of congenital adrenal hyperplasia (CAH), due to mutations in the CYP21A2 gene. Approximately 75% of patients with classical form of CAH have severe impairment of 21-hydroxylase activity.

METHODS

We have performed direct molecular diagnosis of the nine common CYP21A2 point mutations in 24 Macedonian CAH patients from 20 unrelated families, using differential PCR and ACRS.

RESULTS

Five of the analysed mutations were detected in 23 patients: 15 patients were homozygous for one mutation, four patients were compound heterozygotes and four patients were heterozygotes. The most common was IVS2-13A/C mutation found in 60.4% of the alleles, followed by Q318X (22.9%), R356W (4.2%), V281L (2.1%) and P30L (2.1%). The concordance of genotype to phenotype in the patients was 83.3% with complete concordance in the genotypes predicting the SW and SV phenotype.

CONCLUSION

The distribution of the detected mutations in the Macedonian CAH patients was similar with those described in other European populations. The genotype-phenotype correlation observed in our patients strengthens the fact that the genotype cannot be completely predictive of phenotype.

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

Neonatal screening for congenital adrenal hyperplasia (CAH) is useful in diagnosing salt wasting form (SW). However, there are difficulties in interpreting positive results in asymptomatic newborns. The main objective is to analyze genotyping as a confirmatory test in children with neonatal positive results. Patients comprised 23 CAH children and 19 asymptomatic infants with persistently elevated 17-hydroxyprogesterone (17OHP) levels. CYP21A2 gene was sequenced and genotypes were grouped according to the enzymatic activity of the less severe allele: A1 null, A2 < 2%, B 3-7%, C > 20%. Twenty-one children with neonatal symptoms and/or 17OHP levels > 80 ng/ml carried A genotypes, except two virilized girls (17OHP < 50 ng/ml) without CAH genotypes. Patients carrying SW genotypes (A1, A2) and low serum sodium levels presented with neonatal 17OHP > 200 ng/ml. Three asymptomatic boys carried simple virilizing genotypes (A2 and B): in two, the symptoms began at 18 months; another two asymptomatic boys had nonclassical genotypes (C). The remaining 14 patients did not present CAH genotypes, and their 17OHP levels were normalized by 14 months of age. Molecular analysis is useful as a confirmatory test of CAH, mainly in boys. It can predict clinical course, identify false-positives and help distinguish between clinical forms of CAH.

Neonatal screening for congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) caused by steroid 21-hydroxylase deficiency occurs in 1:16,000-1:20,000 births. If not promptly diagnosed and treated, CAH can cause death in early infancy from shock, hyponatremia and hyperkalemia. Affected girls usually have ambiguous genitalia but boys appear normal; therefore, newborn babies are commonly screened for CAH in the US and many other countries. By identifying babies with severe, salt-wasting CAH before they develop adrenal crises, screening reduces morbidity and mortality, particularly among affected boys. Diagnosis is based on elevated levels of 17-hydroxyprogesterone, the preferred substrate for steroid 21-hydroxylase. Initial testing usually involves dissociation-enhanced lanthanide fluorescence immunoassay that has a low positive predictive value (about 1%), which leads to many follow-up evaluations that have negative results. The positive predictive value might be improved by second-tier screening using DNA-based methods or liquid chromatography followed by tandem mass spectrometry, but these methods are not widely adopted. Cost estimates for such screening range from US$20,000 to $300,000 per life-year saved. In babies with markedly abnormal screen results, levels of serum electrolytes and 17-hydroxyprogesterone should be immediately determined, but the most reliable way to diagnose CAH is measurement of levels of steroid precursors after stimulation with cosyntropin.

Functional glucocorticoid receptor gene variants do not underlie the high variability of 17-hydroxyprogesterone screening values in healthy newborns

OBJECTIVE

17-Hydroxyprogesterone (17-OHP) screening for classical congenital adrenal hyperplasia (CAH) is part of many newborn screening programs worldwide. Cut-off values are relatively high, and screening sensitivity does not reach 100%. Recently, the glucocorticoid receptor (GR) N363S-variant has been linked to relatively low degree of virilization and comparatively lower 17-OHP serum concentrations in clinically diagnosed female CAH patients. We sought to determine whether functional GR gene variants, either increasing (N363S, BclI) or decreasing GR sensitivity (R23K), underlie the variable 17-OHP screening levels in healthy newborns.

DESIGN

GR genotypes were compared with 17-OHP screening values in 1000 random samples from routine screening. 17-OHP was measured by conventional immunoassay (TRFIA) and a liquid chromatography-tandem mass spectrometry method (LC-MS/MS), which has been shown to increase screening specificity by steroid profiling and avoiding cross-reactions of the 17-OHP-antibody.

RESULTS

There was no significant association of 17-OHP with GR genotypes, even after inclusion of gestational and postnatal age as covariates. However, among LC-MS/MS steroid measurements, we observed some unexpected trends, including lower 11-deoxycortisol concentrations in both 363S- and 23K-carriers. For carriers of the frequent BclI variant, linear regression analysis revealed a significant increase of 4-androstenedione levels with every mutant allele inherited.

CONCLUSIONS

Functional GR variants do not underlie the variation of 17-OHP values observed in healthy individuals. However, whether and to which extent genetically determined differences in individual GR sensitivity influence 17-OHP screening levels in conditions of a pathological hypothalamus-pituitary-adrenal gland-axis stimulation and thus may explain false-negative screening results in those affected by CAH remains to be investigated.

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.

Identification of frequency and distribution of the nine most frequent mutations among patients with 21-hydroxylase deficiency in Turkey

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders mainly due to defects in the steroid 21-hydroxylase (CYP21A2) gene.

METHODS

To determine the mutational spectrum in the Turkish population, the CYP21A2 active gene was analyzed in 100 unrelated patients with the classical form of 21-hydroxylase deficiency using PCR and RFLP.

RESULTS

Mutations were detected in 78 patients: 64 patients were homozygous for one mutation, seven patients were compound heterozygous with different mutations on each chromosome, two patients were homozygous for two different mutations, five patients were heterozygous, and 22 patients harbored none of the tested mutations. The most frequent mutation was IVS2-13A/C (28.5%), followed by large gene deletion (17%), Q318X (11.5%), I172N (4%), V281L (3.5%), R356W (3.5%), 8-bp (3%), complex alleles (2%), P30L (1%) and E6 cluster (1%).

CONCLUSION

The distribution of mutation frequencies in our study was slightly different from those previously reported in Turkey and in other parts of the world.

False negative 17-hydroxyprogesterone screening in children with classical congenital adrenal hyperplasia

We report 5 out of 214 children with classical congenital adrenal hyperplasia (CAH) that was not detected by neonatal 17-Hydroxyprogesterone screening. Therefore, diagnosis was only based on a suspect clinical picture and subsequent re-evaluation. In addition to 3 patients suffering from the simple virilizing form of CAH and not reported so far, the remaining 2 children whose CAH was missed by the screening suffered from the severe salt-wasting form. This report underlines the importance of a careful clinical investigation of newborns to detect signs of genital virilization. The differential diagnosis of classical CAH should be kept in mind even if neonatal screening is reported to be normal.

Prenatal and neonatal diagnosis and treatment of congenital adrenal hyperplasia

BACKGROUND

Clinical management of patients with congenital adrenal hyperplasia (CAH) involves treating hormonal deficiencies, addressing issues related to genital ambiguity, avoiding morbidities and communicating with the family about risk of CAH in other members. This article briefly reviews the prenatal and neonatal diagnosis of CAH caused by steroid 21-hydroxylase deficiency, as well as treatment options and neonatal screening approaches.

CONCLUSIONS

Screening for CAH can reduce adrenal crises, avoid incorrect sex assignments, lower mortality (especially in males) and avoid inappropriate somatic growth and precocious puberty.

How many deaths can be prevented by newborn screening for congenital adrenal hyperplasia?

BACKGROUND/AIMS

Congenital adrenal hyperplasia (CAH) is increasingly being included in newborn screening programs. Screening can prevent neonatal mortality in children with salt-wasting CAH, but the number of deaths prevented is not known. Cost-effectiveness analyses of screening require estimates of the probability of mortality in CAH.

METHODS

We reviewed the literature to identify cohort studies of children with CAH ascertained clinically in the absence of screening. We abstracted the numbers of infant deaths attributable to CAH. We also addressed sex ratios among children with clinically detected CAH and the contribution of ascertainment bias to unbalanced ratios.

RESULTS

The evidence suggests a probability of infant death due to adrenal crises in salt-wasting CAH of 4% or less in contemporary advanced economies without screening for CAH. This is lower than previous estimates, although the rate of mortality could be considerably higher in populations with limited clinical awareness or access.

CONCLUSION

Although screening for CAH is conducted in a number of countries, further research is still needed to provide reliable estimates on the numbers of prevented deaths, along with evidence-based assessments of the potential benefits, harms, and costs of screening.

Reproductive outcome of women with 21-hydroxylase-deficient nonclassic adrenal hyperplasia

CONTEXT

Because many women with 21-hydroxylase (21-OH)-deficient nonclassic adrenal hyperplasia (NCAH) carry at least one allele affected by a severe mutation of CYP21, they are at risk for giving birth to infants with classic adrenal hyperplasia (CAH).

OBJECTIVE

Our objective was to determine the frequency of CAH and NCAH infants born to mothers with 21-OH-deficient NCAH.

DESIGN AND SETTING

We conducted an international multicenter retrospective/prospective study.

PATIENTS AND METHODS

The outcome of 203 pregnancies among 101 women with 21-OH-deficient NCAH was reviewed. The diagnosis of 21-OH-deficient NCAH was established by a basal or post-ACTH-stimulation 17-hydroxyprogesterone level of more than 10 ng/ml (30.3 nmol/liter). When possible, genotype analyses were performed to confirm CAH or NCAH in the offspring.

RESULTS

Of the 203 pregnancies, 138 (68%) occurred before the mother's diagnosis of NCAH and 65 (32%) after the diagnosis. Spontaneous miscarriages occurred in 35 of 138 pregnancies (25.4%) before the maternal diagnosis of NCAH, and in only four of 65 pregnancies (6.2%) after the diagnosis (P < 0.002). Four (2.5%; 95% confidence interval, 0.7-6.2%) of the 162 live births were diagnosed with CAH. To date, 24 (14.8%; 95% confidence interval, 9.0-20.6%) children, 13 girls and 11 boys, have been diagnosed with NCAH. The distribution of NCAH children and their mothers varied significantly by ethnicity (P < 0.0001, for both).

CONCLUSIONS

The risk of a mother with 21-OH-deficient NCAH for giving birth to a child affected with CAH is 2.5%; at least 14.8% of children born to these mothers have NCAH.

Diagnosis and management of congenital adrenal hyperplasia

Congenital adrenal hyperplasia is the name applied to a class of autosomal recessive disorders resulting from deficiency of one of five enzymes necessary for cortisol synthesis by the adrenal cortex. Congenital adrenal hyperplasia is most often attributable to steroid 21-hydroxylase deficiency, accounting for more than 90% of cases. This discussion will be limited to the most common form of the disease, highlighting methods of diagnostic screening and challenges in disease management.