Use of steroid profiling by UPLC-MS/MS as a second tier test in newborn screening for congenital adrenal hyperplasia: the Utah experience

How mass spectrometry revolutionized newborn screening

This article offers a personal account of a remarkable journey spanning over 30 years of applied mass spectrometry in a clinical setting. It begins with the author's inspiration from a clinician's story of rescuing a child from near death with a revolutionary therapeutic intervention. Motivated by this experience, the author delved into the field of chemistry and mass spectrometry to solve an analytical challenge. The breakthrough came with the development of the first front-line diagnostic test performed by MS/MS, which focused on analyzing acylcarnitines to detect and diagnose inherited disorders related to fatty acid and branched-chain amino acid catabolism. Building upon this success, the author expanded the application of the method to dried blood spots, incorporating additional analytical components such as essential amino acids. The result was a groundbreaking multiplex assay capable of screening newborns for more than 30 inherited metabolic conditions with just one test. This novel approach laid the foundation for a targeted metabolomics platform that facilitated the identification of new animal models of metabolic disease through screening the offspring of genetically modified adults. The development and utilization of MS/MS with UPLC has led to the creation of new assays for biomarkers of metabolic disease, benefiting both the diagnosis and therapeutic monitoring of these conditions. The article provides compelling examples from the author's laboratory, highlighting the value and vast applications of these methods in the field of metabolic disease research.

The use of liquid chromatography-tandem mass spectrometry in newborn screening for congenital adrenal hyperplasia: improvements and future perspectives

Newborn screening for congenital adrenal hyperplasia using 17-hydroxyprogesterone by immunoassay remains controversial despite screening been available for almost 40 years. Screening is confounded by poor immunoassay specificity, fetal adrenal physiology, stress, and illness which can result in a large number of false positive screening tests. Screening programmes apply higher screening thresholds based on co-variates such as birthweight or gestational age but the false positive rate using immunoassay remains high. Mass spectrometry was first applied to newborn screening for congenital adrenal hyperplasia over 15 years ago. Elevated 17-hydroxprogesterone by immunoassay can be retested with a specific liquid chromatography tandem mass spectrometry assay that may include additional steroid markers. Laboratories register with quality assurance programme providers to ensure accurate steroid measurements. This has led to improvements in screening but there are additional costs and added laboratory workload. The search for novel steroid markers may inform further improvements to screening. Studies have shown that 11-oxygenated androgens are elevated in untreated patients and that the adrenal steroidogenesis backdoor pathway is more active in babies with congenital adrenal hyperplasia. There is continual interest in 21-deoxycortisol, a specific marker of 21-hydroxylase deficiency. The measurement of androgenic steroids and their precursors by liquid chromatography tandem mass spectrometry in bloodspots may inform improvements for screening, diagnosis, and treatment monitoring. In this review, we describe how liquid chromatography tandem mass spectrometry has improved newborn screening for congenital adrenal hyperplasia and explore how future developments may inform further improvements to screening and diagnosis.

International Newborn Screening Practices for the Early Detection of Congenital Adrenal Hyperplasia

INTRODUCTION

Newborn screening (NBS) programmes vary internationally in their approach to screening. Guidelines for congenital adrenal hyperplasia (CAH) screening recommend the use of two-tier testing and gestational age cutoffs to minimise false-positive results. The aims of this study were to describe (1) the approaches; (2) protocols used; and (3) available outcomes for CAH screening internationally.

METHODS

All members of the International Society for Neonatal Screening were asked to describe their CAH NBS protocols, with an emphasis on the use of second-tier testing, 17-hydroxyprogesterone (17OHP) cutoffs, and gestational age and birth weight adjustments. If available, screening outcomes were requested.

RESULTS

Representatives from 23 screening programmes provided data. Most (n = 14; 61%) recommend sampling at 48-72 h of life. Fourteen (61%) use single-tier testing and 9 have a two-tier testing protocol. Gestational age cutoffs are used in 10 programmes, birth weight cutoffs in 3, and a combination of both in 9. One programme does not use either method of adjusting 17OHP cutoffs. Case definition of a positive test and the response to a positive test differed between programmes.

CONCLUSIONS

We have demonstrated significant variation across all aspects of NBS for CAH, including timing, the use of single versus two-tier testing and cutoff interpretation. Collaboration between international screening programmes and implementation of new techniques to improve screen efficacy will facilitate ongoing expansion and quality improvement in CAH NBS.

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.

Multiple 17-OHP Cutoff Co-Variates Fail to Improve 21-Hydroxylase Deficiency Screening Accuracy

To improve the positive predictive value (PPV) of newborn screening for 21-hydroxylase deficiency (21OHD), co-variates have been used to modify 17-hydroxyprogesterone (17OHP) cutoffs. The objective of this study is to evaluate whether 17OHP screening cutoffs adjusted for both collection time (CT) and birth weight (BW) improved the sensitivity and PPV of 21OHD screening. Unaffected newborn screening samples were stratified based on BW and CT to establish 17OHP concentration cutoffs at the 95th and 99th percentile. These cutoffs were applied to a cohort of confirmed cases of 21OHD to determine the sensitivity and PPV of the modified screening parameters. 17OHP cutoffs at the 99th percentile, adjusted for BW and CT, had a sensitivity of 96.3% and a specificity of 98.9%, but a relatively low PPV (0.130) for the identification of 21OHD and did not detect all cases. Use of the 95th percentile further increased sensitivity to 98.1% but resulted in a notably lower PPV (0.027). Alternative approaches that do not rely exclusively on 17OHP are needed to improve newborn screening accuracy for 21OHD.

Evaluation of a New Laboratory Protocol for Newborn Screening for Congenital Adrenal Hyperplasia in New Zealand

Between 2005 and 2021, 49 cases of classical congenital adrenal hyperplasia were diagnosed in New Zealand, 39 were detected in newborns and 10 were not detected by screening. Currently, for every case of CAH detected by screening, 10 false-positive tests are encountered. Second-tier liquid chromatography-tandem mass spectrometry (LCMSMS) has the potential to improve screening sensitivity and specificity. A new laboratory protocol for newborn screening for CAH was evaluated. Birthweight-adjusted thresholds for first- and second-tier 17-hydroxyprogesterone, second-tier 21-deoxycortisol and a steroid ratio were applied to 4 years of newborn screening data. The study was enriched with 35 newborn screening specimens from confirmed CAH cases. Newborn screening was conducted on 232,542 babies, and 11 cases of classical CAH were detected between 2018 and 2021. There were 98 false-positive tests (specificity 99.96%, PPV = 10.1%) using the existing protocol. Applying the new protocol, the same 11 cases were detected, and there were 13 false-positive tests (sensitivity > 99.99%, PPV = 45.8%, (X2 test p < 0.0001). Incorporating the retrospective specimens, screening sensitivity for classical CAH was 78% (existing protocol), compared to 87% for the new protocol (X2 test p = 0.1338). Implementation of LCMSMS as a second-tier test will improve newborn screening for classical CAH in New Zealand.

Simultaneous quantitation of 17 endogenous adrenal corticosteroid hormones in human plasma by UHPLC-MS/MS and their application in congenital adrenal hyperplasia screening

Accurate investigation of adrenal hormone levels plays a vital role in pediatric endocrinology for the detection of steroid-related disorders. This study aims to develop a straightforward, sensitive UHPLC-MS/MS method to quantify 17 endogenous adrenal corticosteroid hormones in human plasma. These hormones are the main ingredients in the synthetic and metabolic pathways of adrenal corticosteroid hormones. Chromatographic separation was achieved on a C18 column before electrospray ionization triple-quadrupole mass spectrometry in multiple reaction monitoring mode with a run time of 7 min. The samples were extracted by liquid-liquid extraction and required no derivatization. Analytical performance was evaluated, including linearity, analytical sensitivity, accuracy, precision, and specificity. Plasma specimens from 32 congenital adrenal hyperplasia (CAH) patients and 30 healthy volunteers were analyzed to further reveal the diagnostic value of multiple steroid hormones in the synthetic and metabolic pathways of adrenal corticosteroid in CAH diagnosis. All hormones were effectively extracted and separated using our method. The method was essentially free from potential interference of isomers or structural analogues. The imprecisions were <10%. The lower limits of quantification varied from 0.05 to 15.0 ng/ml. Good linearity coefficients (r² > 0.998) were also obtained for most hormones in the required concentration range, except for 21-deoxycortisol (r² = 0.9967) and androstenediol (r² = 0.9952). The recoveries for the steroid hormones ranged from 91.7 to 109.8%. We developed the UHPLC-MS/MS method for the simultaneous measurement of steroid hormones. The results showed that measurement of steroid hormones simultaneously could improve the diagnostic efficiency of CAH.

Incorporation of second-tier tests and secondary biomarkers to improve positive predictive value (PPV) rate in newborn metabolic screening program

BACKGROUND

Nowadays, neonatal screening has become an essential part of routine newborn care in the world. This is a non-invasive evaluation that evaluated inborn errors of metabolisms (IEMs) using tandem mass spectrometry (LC-MS/MS) for the evaluation of the baby's risk of certain metabolic disorders.

METHODS

This retrospective study was conducted on 39987 Iranian newborns who were referred to Nilou Medical Laboratory, Tehran, Iran, for newborn screening programs of IEMs. We incorporated second-tier tests and secondary biomarkers to improve positive predictive value (PPV).

RESULTS

Statistical data were recorded via call interviewing in 6-8 months after their screening tests. The overall prevalence of IEM was 1:975. The mean age of all participants was 3.9 ± 1.1 days; 5.1% of participants were over 13 days and 7.7% were preterm or underweight. A total of 11384 (29.4%) of the cases were born in a consanguineous family. The type of delivery was the cesarean section in 8332 (51.3%) valid cases. The neonatal screening results had an overall negative predictive value (NPV) of 100% and the overall PPV of 40.2%. The false-positive rate was 0.15%.

CONCLUSION

This study showed a high incidence of metabolic disease due to a high rate of consanguineous marriages in Iran and indicated that incorporation of second-tier tests and secondary biomarkers improves PPV of neonatal screening programs.

A proof of concept of a machine learning algorithm to predict late-onset 21-hydroxylase deficiency in children with premature pubic hair

In children with premature pubarche (PP), late onset 21-hydroxylase deficiency (21-OHD), also known as non-classical congenital adrenal hyperplasia (NCCAH), can be routinely ruled out by an adrenocorticotropic hormone (ACTH) test. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a quantitative assay of the circulating steroidome can be obtained from a single blood sample. We hypothesized that, by applying multivariate machine learning (ML) models to basal steroid profiles and clinical parameters of 97 patients, we could distinguish children with PP from those with NCCAH, without the need for ACTH testing. Every child presenting with PP at the Trousseau Pediatric Endocrinology Unit between 2016 and 2018 had a basal and stimulated steroidome. Patients with central precocious puberty were excluded. The first set of patients (year 1, training set, n = 58), including 8 children with NCCAH verified by ACTH test and genetic analysis, was used to train the model. Subsequently, a validation set of an additional set of patients (year 2, n = 39 with 5 NCCAH) was obtained to validate our model. We designed a score based on an ML approach (orthogonal partial least squares discriminant analysis). A metabolic footprint was assigned for each patient using clinical data, bone age, and adrenal steroid levels recorded by LC-MS/MS. Supervised multivariate analysis of the training set (year 1) and validation set (year 2) was used to validate our score. Based on selected variables, the prediction score was accurate (100%) at differentiating premature pubarche from late onset 21-OHD patients. The most significant variables were 21-deoxycorticosterone, 17-hydroxyprogesterone, and 21-deoxycortisol steroids. We proposed a new test that has excellent sensitivity and specificity for the diagnosis of NCCAH, due to an ML approach.

21-Deoxycortisol is a Key Screening Marker for 21-Hydroxylase Deficiency

OBJECTIVES

To assess whether 21-deoxycortisol (21deoxy) can be used to predict 21-hydroxylase deficiency (21OHD) in newborns and to evaluate the influence of gestational age and the timing of collection on 21deoxy concentrations.

STUDY DESIGN

17-hydroxyprogesterone (17OHP) and 21deoxy levels were measured in 906 newborn screening specimens (851 unaffected newborns, 55 confirmed cases of 21OHD) to compare their ability to identify babies with 21OHD. In addition, these 2 steroids were assessed in the unaffected cohort to determine the influence of gestational age (ranging from 23 to 42 weeks) and the timing of specimen collection on the measured concentrations.

RESULTS

The gestational age of the newborn impacted both 17OHP and 21deoxy concentrations, but the degree of influence was more substantial for 17OHP. Timing of collection did not affect 21deoxy concentration. Moreover, 21deoxy was a better predictor of 21OHD status compared with 17OHP, with little overlap in concentrations between the unaffected population and confirmed cases of 21OHD. A streamlined decision tree using solely 21deoxy (cutoff value, 0.85 ng/mL) yielded a 91.7% positive predictive value for 21OHD screening.

CONCLUSIONS

Our findings demonstrate that 21deoxy is a key disease marker of 21OHD and can be used to improve the accuracy of newborn screening for this disorder.

Rapidity and Precision of Steroid Hormone Measurement

Steroids are present in all animals and plants, from mammals to prokaryotes. In the medical field, steroids are commonly classified as glucocorticoids, mineralocorticoids, and gonadal steroid hormones. Monitoring of hormones is useful in clinical and research fields for the assessment of physiological changes associated with aging, disease risk, and the diagnostic and therapeutic effects of various diseases. Since the discovery and isolation of steroid hormones, measurement methods for steroid hormones in biological samples have advanced substantially. Although immunoassays (IAs) are widely used in daily practice, mass spectrometry (MS)-based methods have been reported to be more specific. Steroid hormone measurement based on MS is desirable in clinical practice; however, there are several drawbacks, including the purchase and maintenance costs of the MS instrument and the need for specialized training of technicians. In this review, we discuss IA- and MS-based methods currently in use and briefly present the history of steroid hormone measurement. In addition, we describe recent advances in IA- and MS-based methods and future applications and considerations.

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.

Clinical guidelines for the diagnosis and treatment of 21-hydroxylase deficiency (2021 revision)

Congenital adrenal hyperplasia is a category of disorders characterized by impaired adrenocortical steroidogenesis. The most frequent disorder of congenital adrenal hyperplasia is 21-hydroxylase deficiency, which is caused by pathogenic variants of CAY21A2 and is prevalent between 1 in 18,000 and 20,000 in Japan. The clinical guidelines for 21-hydroxylase deficiency in Japan have been revised twice since a diagnostic handbook in Japan was published in 1989. On behalf of the Japanese Society for Pediatric Endocrinology, the Japanese Society for Mass Screening, the Japanese Society for Urology, and the Japan Endocrine Society, the working committee updated the guidelines for the diagnosis and treatment of 21-hydroxylase deficiency published in 2014, based on recent evidence and knowledge related to this disorder. The recommendations in the updated guidelines can be applied in clinical practice considering the risks and benefits to each patient.

Clinical applications of genetic analysis and liquid chromatography tandem-mass spectrometry in rare types of congenital adrenal hyperplasia

BACKGROUND

Our study aims to summarize the clinical characteristics of rare types of congenital adrenal hyperplasia (CAH) other than 21-hydroxylase deficiency (21-OHD), and to explore the clinical applications of genetic analysis and liquid chromatography tandem-mass spectrometry (LC-MS/MS) in rare CAH.

METHODS

We retrospectively analysed the clinical data of 5 rare cases of CAH admitted to our hospital and summarized their clinical manifestations, auxiliary examinations, diagnosis and mutational spectrum.

RESULTS

After gene sequencing, complex heterozygous variants were detected in all patients (2 cases were lipoid congenital adrenal hyperplasia (LCAH), 11β-hydroxylase deficiency (11β-OHD), 3β-hydroxysteroid dehydrogenase deficiency (3β-HSD deficiency) and P450 oxidoreductase deficiency (PORD) each accounted for 1 case), which were consistent with their clinical manifestations. Among them, 4 novel variants were detected, including c.650 + 2 T > A of the StAR gene, c.1145 T > C (p. L382P) of the CYP11B1 gene, c.1622C > T (p. A541V) and c.1804C > T (p. Q602 *) of the POR gene. The LC-MS/MS results for steroid hormones in patients were also consistent with their genetic variants: 2 patients with LCAH showed a decrease in all steroid hormones; 11β-OHD patient showed a significant increase in 11-deoxycortisol and 11-deoxycorticosterone; patient with 3β-HSD deficiency showed a significant increase in DHEA; and PORD patient was mainly characterized by elevated 17OHP, progesterone and impaired synthesis of androgen levels.

CONCLUSIONS

The clinical manifestations and classification of CAH are complicated, and there are cases of missed diagnosis or misdiagnosis. It's necessary to combine the analysis of clinical manifestations and auxiliary examinations for diagnosis; if necessary, LC-MS/MS analysis of steroid hormones or gene sequencing is recommended for confirming diagnosis and typing.

Birth Weight- or Gestational Age-adjusted Second-tier LCMSMS Cutoffs Improve Newborn Screening for CAH in New Zealand

CONTEXT

The positive predictive value of newborn screening for congenital adrenal hyperplasia (CAH) in New Zealand is approximately 10%. The use of a second tier liquid chromatography-tandem mass spectrometry bloodspot steroid profile test with birth weight- or gestational age-adjusted screening cutoffs may result in further screening improvements.

METHODS

Three years of newborn screening data with additional second-tier steroid metabolites was evaluated (n = 167 672 births). Data from babies with a negative screening test and confirmed CAH cases were compared. First- and second-tier steroid measurements were correlated with both birth weight and gestational age. Analysis of variance was used to determine birth weight and gestational age groups. Screening cutoffs were determined and applied retrospectively to model screening performance.

RESULTS

First-tier immunoassay data correlated better with gestational age than with birth weight, but there was no difference with second-tier steroid measurements. Four distinct birth weight and gestational age groups were established for 17-hydroxyprogesterone and a steroid ratio measurement. Application of 97.5th percentile second-tier birth weight- or gestational age-adjusted cutoffs would result in 10 positive tests over the period of the study with 8 true-positive screens and 2 false-positive tests. The positive predictive value of screening would be increased from 10.8% to 80%.

CONCLUSIONS

The use of either birth weight- or gestational age-adjusted cutoffs for second-tier screening tests can significantly reduce the false positive rate of newborn screening for CAH in New Zealand without loss in screening sensitivity.

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.

Implementing steroid profiling by liquid chromatography-tandem mass spectrometry improves newborn screening for congenital adrenal hyperplasia in New Zealand

OBJECTIVE

To evaluate the impact of a liquid chromatography-tandem mass spectrometry (LCMSMS) second-tier test on newborn screening for congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) in New Zealand.

DESIGN

In a prospective study, a LCMSMS method to measure 17-hydroxyprogesterone (17OHP) was adapted to measure four additional steroids. Steroid concentrations were collected on all second-tier CAH screening tests while protocols remained unchanged. Steroid ratio parameters with recommended or published screening cuts-offs were evaluated for their impact on newborn screening performance.

MEASUREMENTS

Precision, accuracy, linearity and recovery of the second-tier LCMSMS method were evaluated. Second-tier specimens were divided in 3 groups; newborn screening bloodspots from neonates with confirmed CAH (n = 7) and 2 groups specimens from neonates with a birthweight (BW) ≤1500 g (n = 795) and with a BW > 1500 g (n = 806) with a negative newborn screening test. Six protocols using four steroid ratio parameters were evaluated. The sensitivity, specificity, false positive rate and positive predictive value of screening was calculated for each protocol.

RESULTS

The LCMSMS method was sufficiently accurate and precise to be used as a second-tier test for CAH. Screening sensitivity remained at 100% for each protocol apart from (17OHP + androstenedione)/cortisol when the highest cut-off of 3.75 was applied. The false positive rate was significantly improved when (17OHP + androstenedione)/cortisol and (17OHP + 21-deoxycortisol)/cortisol were evaluated with cut-offs of 2.5 and 1.5 respectively (P < .01) and both with a positive predictive value of 64%.

CONCLUSIONS

A second-tier LCMSMS newborn screening test for CAH offers significant improvements to screening specificity without any other changes to screening protocols.

[Newborn screening for congenital adrenal hyperplasia in France]

Congenital Adrenal Hyperplasia (CAH) is a genetic disorder, mostly (95%) due to CYP21A2 mutations. Its incidence in France is 1/15,000 to 1/16,000 births. The screening of newborns in France is effective since 1996, by using a 17-hydroxyprogesterone dosage on a dried blood spot. This screening allowed, as in other countries, a decrease in mortality and in morbidity by earlier management of adrenal crisis usually symptomatic from the 2^nd week after birth. The French Newborn Screening has for now adopted the two-tier screens on the same dried blood spot, using a fluoroimmunoassay on both screens. This approach provides a high sensitivity, but has also a low positive predictive value. New strategies including the LC-MS/MS method can be considered in the future.

Development of Strategies to Decrease False Positive Results in Newborn Screening

The expansion of national newborn screening (NBS) programmes has provided significant benefits in the diagnosis and early treatment of several rare, heritable conditions, preventing adverse health outcomes for most affected infants. New technological developments have enabled the implementation of testing panel covering over 50 disorders. Consequently, the increment of false positive rate has led to a high number of healthy infants recalled for expensive and often invasive additional testing, opening a debate about the harm-benefit ratio of the expanded newborn screening. The false-positive rate represents a challenge for healthcare providers working in NBS systems. Here, we give an overview on the most commonly used strategies for decreasing the adverse effects due to inconclusive screening results. The focus is on NBS performance improvement through the implementation of analytical methods, the application of new and more informative biomarkers, and by using post-analytical interpretive tools. These strategies, used as part of the NBS process, can to enhance the positive predictive value of the test and reduce the parental anxiety and healthcare costs related to the unnecessary tests and procedures.

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.

Application of Principal Component Analysis to Newborn Screening for Congenital Adrenal Hyperplasia

PURPOSE

Newborn screening laboratories are challenged to develop reporting algorithms that accurately identify babies at increased risk for congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD). Screening algorithms typically use cutoff values for a key steroid(s) and include considerations for covariates, such as gestational age or birth weight, but false-positive and false-negative results are still too frequent, preventing accurate assessments. Principal component analysis (PCA) is a statistical method that reduces high-dimensional data to a small number of components, capturing patterns of association that may be relevant to the outcome of interest. To our knowledge, PCA has not been evaluated in the newborn screening setting to determine whether it can improve the positive predictive value of 21OHD screening.

METHODS

PCA was applied to a data set of 920 newborns with measured concentrations of 5 key steroids that are known to be perturbed in patients with 21OHD. A decision tree for the known outcomes (confirmed 21OHD cases and unaffected individuals) was created with 2 principal components as predictors. The effectiveness of the PCA-derived decision tree was compared with the current algorithm.

RESULTS

PCA improved the positive predictive value of 21OHD screening from 20.0% to 66.7% in a retrospective study comparing the current algorithm to a tree-based algorithm using PCA-derived variables. The streamlined PCA-derived decision tree, comprising only 3 assessment points, greatly simplified the 21OHD reporting algorithm.

CONCLUSIONS

This first report of PCA applied to newborn screening for 21OHD demonstrates enhanced detection of affected individuals within the unaffected population.

Androgen excess and diagnostic steroid biomarkers for nonclassic 21-hydroxylase deficiency without cosyntropin stimulation

OBJECTIVES

The clinical presentation of patients with nonclassic 21-hydroxylase deficiency (N21OHD) is similar with that for other disorders of androgen excess. The diagnosis of N21OHD typically requires cosyntropin stimulation. Additionally, the management of such patients is limited by the lack of reliable biomarkers of androgen excess. Herein, we aimed to: (1.) compare the relative contribution of traditional and 11-oxyandrogens in N21OHD patients and (2.) identify steroids that accurately diagnose N21OHD with a single baseline blood draw.

DESIGN

We prospectively enrolled patients who underwent a cosyntropin stimulation test for suspected N21OHD in two tertiary referral centers between January 2016 and August 2019.

METHODS

Baseline sera were used to quantify 15 steroids by liquid chromatography-tandem mass spectrometry. Logistic regression modeling was implemented to select steroids that best discriminate N21OHD from controls.

RESULTS

Of 86 participants (72 females), median age 26, 32 patients (25 females) had N21OHD. Age, sex distribution, and BMI were similar between patients with N21OHD and controls. Both testosterone and androstenedione were similar in patients with N21OHD and controls, while four 11-oxyandrogens were significantly higher in patients with N21OHD (ratios between medians: 1.7 to 2.2, P < 0.01 for all). 17α-Hydroxyprogesterone (6.5-fold), 16α-hydroxyprogesterone (4.1-fold), and 21-deoxycortisol (undetectable in 80% of the controls) were higher, while corticosterone was 3.6-fold lower in patients with N21OHD than in controls (P < 0.001). Together, baseline 17α-hydroxyprogesterone, 21-deoxycortisol, and corticosterone showed perfect discrimination between N21OHD and controls.

CONCLUSIONS

Adrenal 11-oxyandrogens are disproportionately elevated compared to conventional androgens in N21OHD. Steroid panels can accurately diagnose N21OHD in unstimulated blood tests.

Measurement of 17-Hydroxyprogesterone by LCMSMS Improves Newborn Screening for CAH Due to 21-Hydroxylase Deficiency in New Zealand

The positive predictive value of newborn screening for congenital adrenal hyperplasia due to 21-hydroxylase deficiency was <2% in New Zealand. This is despite a bloodspot second-tier immunoassay method for 17-hydroxyprogesterone measurement with an additional solvent extract step to reduce the number of false positive screening tests. We developed a liquid chromatography tandem mass spectrometry (LCMSMS) method to measure 17-hydroxyprogesterone in bloodspots to replace our current second-tier immunoassay method. The method was assessed using reference material and residual samples with a positive newborn screening result. Correlation with the second-tier immunoassay was determined and the method was implemented. Newborn screening performance was assessed by comparing screening metrics 2 years before and 2 years after LCMSMS implementation. Screening data analysis demonstrated the number of false positive screening tests was reduced from 172 to 40 in the 2 years after LCMSMS implementation. The positive predictive value of screening significantly increased from 1.71% to 11.1% (X2 test, p < 0.0001). LCMSMS analysis of 17OHP as a second-tier test significantly improves screening specificity for CAH due to 21-hydroxylase deficiency in New Zealand.

Wisconsin's Screening Algorithm for the Identification of Newborns with Congenital Adrenal Hyperplasia

Newborn screening for congenital adrenal hyperplasia (CAH) has one of the highest false positive rates of any of the diseases on the Wisconsin panel. This is largely due to the first-tier immune assay cross-reactivity and physiological changes in the concentration of 17-hydroxyprogesterone during the first few days of life. To improve screening for CAH, Wisconsin developed a second-tier assay to quantify four different steroids (17-hydroxyprogesterone, 21-deoxycortisol, androstenedione, and cortisol) by liquid chromatography-tandem mass spectrometry (LC-MSMS) in dried blood spots. From validation studies which included the testing of confirmed CAH patients, Wisconsin established its own reporting algorithm that incorporates steroid concentrations as well as two different ratios-the birth weight and the collection time-to identify babies at risk for CAH. Using the newly developed method and algorithm, the false positive rate for the CAH screening was reduced by 95%. Patients with both classical forms of CAH, salt-wasting and simple virilizing, were identified. This study replicates and expands upon previous work to develop a second-tier LC-MSMS steroid profiling screening assay for CAH. The validation and prospective study results provide evidence for an extensive reporting algorithm that incorporates multiple steroids, birth weight, and collection times.

Absence of Testicular Adrenal Rest Tumors in Newborns, Infants, and Toddlers with Classical Congenital Adrenal Hyperplasia

INTRODUCTION

Testicular adrenal rest tumors (TART) are a known consequence for males with classical congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. TART are associated with potential infertility in adults. However, little is known about TART in very young males with CAH.

OBJECTIVE

We assessed the presence of TART in newborn, infant, and toddler males with classical CAH via scrotal ultrasound.

METHODS

Males with CAH had scrotal ultrasounds during the first 4 years of life, evaluating testes for morphology, blood flow, and presence of TART. Newborn screen 17-hydroxyprogesterone (17-OHP) and serum 17-OHP at the time of ultrasound were recorded. Bone ages were considered very advanced if ≥2 SD above chronological age.

RESULTS

Thirty-one ultrasounds in 16 males were performed. An initial ultrasound was obtained in four newborns at diagnosis (6.8 ± 2.1 days), six infants (2.2 ± 0.9 months), and six toddlers (2.4 ± 0.9 years). Eleven males had at least one repeat ultrasound. A large proportion (11/16) were in poor hormonal control with an elevated 17-OHP (325 ± 298 nmol/L). One infant was in very poor hormonal control (17-OHP 447 nmol/L) at initial ultrasound, and two toddlers had advanced bone ages (+3.2 and +4.5 SD) representing exposure to postnatal androgens. However, no TART were detected in any subjects.

CONCLUSIONS

TART were not found by scrotal ultrasound in males up to 4 years of age with classical CAH despite settings with expected high ACTH drive. Further research into the occurrence of TART in CAH may elucidate factors that contribute to the detection and individual predisposition to TART.

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.

The role of steroid metabolome analysis for the diagnosis and follow-up of adrenocortical tumors

The diagnostic work-up of adrenal tumors, often incidentally discovered, has emerged as an ever-increasing diagnostic problem for clinical endocrinologists. No imaging modality has sufficiently high sensitivity and specificity at differentiating benign from malignant adrenal lesions. It has long been observed that adrenocortical carcinomas (ACCs) present an immature pattern of steroidogenesis, dominated by steroid hormone precursors. Modern mass spectrometry-based assays can generate multi-steroid metabolite profiles in urine collections, which can detect differences between ACCs and benign adrenocortical adenomas (ACAs). This review summarizes the promising results of studies which have applied steroid metabolite profiling in biological fluids as a novel diagnostic tool for patients with adrenal tumors, as well as the challenges and limitations of this approach. It also discusses the potential role of steroid profiling as a biochemical surveillance tool to detect recurrence in patients who have undergone resection of an ACC.

Role of Mass Spectrometry in Clinical Endocrinology

The advent of mass spectrometry into the clinical laboratory has led to an improvement in clinical management of several endocrine diseases. Liquid chromatography tandem mass spectrometry found some of its first clinical applications in the diagnosis of inborn errors of metabolism, in quantitative steroid analysis, and in drug analysis laboratories. Mass spectrometry assays offer analytical sensitivity and specificity that is superior to immunoassays for many analytes. This article highlights several areas of clinical endocrinology that have witnessed the use of liquid chromatography tandem mass spectrometry to improve clinical outcomes.

An untargeted metabolomics method for archived newborn dried blood spots in epidemiologic studies

INTRODUCTION

For pediatric diseases like childhood leukemia, a short latency period points to in-utero exposures as potentially important risk factors. Untargeted metabolomics of small molecules in archived newborn dried blood spots (DBS) offers an avenue for discovering early-life exposures that contribute to disease risks.

OBJECTIVES

The purpose of this study was to develop a quantitative method for untargeted analysis of archived newborn DBS for use in an epidemiological study (California Childhood Leukemia Study, CCLS).

METHODS

Using experimental DBS from the blood of an adult volunteer, we optimized extraction of small molecules and integrated measurement of potassium as a proxy for blood hematocrit. We then applied this extraction method to 4.7-mm punches from 106 control DBS samples from the CCLS. Sample extracts were analyzed with liquid chromatography high resolution mass spectrometry (LC-HRMS) and an untargeted workflow was used to screen for metabolites that discriminate population characteristics such as sex, ethnicity, and birth weight.

RESULTS

Thousands of small molecules were measured in extracts of archived DBS. Normalizing for potassium levels removed variability related to varying hematocrit across DBS punches. Of the roughly 1,000 prevalent small molecules that were tested, multivariate linear regression detected significant associations with ethnicity (3 metabolites) and birth weight (15 metabolites) after adjusting for multiple testing.

CONCLUSIONS

This untargeted workflow can be used for analysis of small molecules in archived DBS to discover novel biomarkers, to provide insights into the initiation and progression of diseases, and to provide guidance for disease prevention.

Neonatal screening for congenital adrenal hyperplasia in Southern Brazil: a population based study with 108,409 infants

Background

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder associated with inborn errors of steroid metabolism. 21-hydroxylase enzyme deficiency occurs in 90 to 95% of all cases of CAH, with accumulation of 17 hydroxyprogesterone (17-OHP). Early diagnosis of CAH based on newborn screening is possible before the development of symptoms and allows proper treatment, correct sex assignment, and reduced mortality rates. This study describes the results obtained in the first year of a public CAH screening program in the state of Rio Grande do Sul, Brazil.

Methods

We reviewed the screening database in search of babies with suspected CAH, that is, altered birth-weight adjusted 17-OHP values at screening. The following data were analyzed for this population: screening 17-OHP values, retest 17-OHP values, serum 17-OHP values for those with confirmed CAH on retest, maternal and newborn data, and family history of CAH. For the screening program, 17-OHP levels are determined on dried blood spots obtained in filter paper with GSP solid phase time-resolved immunofluorescence.

Results

Of 108,409 newborns screened, eight were diagnosed with CAH (four males, four females). The incidence of CAH in the state was 1:13,551. Six cases were identified as classic salt-wasting CAH and two were cases of virilizing CAH. The positive predictive value (PPV) of the initial screening (before diagnostic confirmation) was 1.6%. The overall rate of false positive results was 0.47%. The number of false positive results was higher among newborns with birth weight < 2000 g.

Conclusion

The present results support the need for CAH screening by the public health care system in the state, and show that the strategy adopted is adequate. PPV and false positive results were similar to those reported for other states of Brazil with similar ethnic backgrounds.

LC-MS based analysis of endogenous steroid hormones in human hair

The quantification of endogenous steroid hormone concentrations in hair is increasingly used as a method for obtaining retrospective information on long-term integrated hormone exposure. Several different analytical procedures have been employed for hair steroid analysis, with liquid chromatography-mass spectrometry (LC-MS) being recognized as a particularly powerful analytical tool. Several methodological aspects affect the performance of LC-MS systems for hair steroid analysis, including sample preparation and pretreatment, steroid extraction, post-incubation purification, LC methodology, ionization techniques and MS specifications. Here, we critically review the differential value of such protocol variants for hair steroid hormones analysis, focusing on both analytical quality and practical feasibility issues. Our results show that, when methodological challenges are adequately addressed, LC-MS protocols can not only yield excellent sensitivity and specificity but are also characterized by relatively simple sample processing and short run times. This makes LC-MS based hair steroid protocols particularly suitable as a high-quality option for routine application in research contexts requiring the processing of larger numbers of samples.

Challenges for Worldwide Harmonization of Newborn Screening Programs

BACKGROUND

Inherited metabolic disorders (IMDs) are caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites. To date, hundreds of IMDs have been identified. Many of these diseases are potentially fatal conditions that are not apparent at birth. Newborn screening (NBS) programs involve the clinical and laboratory examination of neonates who exhibit no health problems, with the aim of discovering those infants who are, in fact, suffering from a treatable condition.

CONTENT

In recent years, the introduction of tandem mass spectrometry has allowed the expansion of screening programs. However, this expansion has brought a high degree of heterogeneity in the IMDs tested among different NBS programs. An attempt to harmonize the metabolic conditions recommended to be screened has been carried out. Two uniform screening panels have been proposed in the US and European Union, by knowledgeable organizations. Here, we review current evidence-based processes to assess and expand NBS programs. We also discuss the IMDs that have recently been introduced in some screening programs, such as severe combined immunodeficiencies, lysosomal storage disorders, and adrenoleukodystrophy.

SUMMARY

NBS programs have been an established public health function for more than 50 years to efficiently and cost-effectively identify neonates with severe conditions. However, NBS is not yet optimal. This review is intended to elucidate the current degree of harmonization of NBS programs worldwide as well as to describe the major controversial points and discuss the multiple challenges that must be confronted in expanded NBS strategies.

The use of mass spectrometry to analyze dried blood spots

Dried blood spots (DBS) typically consist in the deposition of small volumes of capillary blood onto dedicated paper cards. Comparatively to whole blood or plasma samples, their benefits rely in the fact that sample collection is easier and that logistic aspects related to sample storage and shipment can be relatively limited, respectively, without the need of a refrigerator or dry ice. Originally, this approach has been developed in the sixties to support the analysis of phenylalanine for the detection of phenylketonuria in newborns using bacterial inhibition test. In the nineties tandem mass spectrometry was established as the detection technique for phenylalanine and tyrosine. DBS became rapidly recognized for their clinical value: they were widely implemented in pediatric settings with mass spectrometric detection, and were closely associated to the debut of newborn screening (NBS) programs, as a part of public health policies. Since then, sample collection on paper cards has been explored with various analytical techniques in other areas more or less successfully regarding large-scale applications. Moreover, in the last 5 years a regain of interest for DBS was observed and originated from the bioanalytical community to support drug development (e.g., PK studies) or therapeutic drug monitoring mainly. Those recent applications were essentially driven by improved sensitivity of triple quadrupole mass spectrometers. This review presents an overall view of all instrumental and methodological developments for DBS analysis with mass spectrometric detection, with and without separation techniques. A general introduction to DBS will describe their advantages and historical aspects of their emergence. A second section will focus on blood collection, with a strong emphasis on specific parameters that can impact quantitative analysis, including chromatographic effects, hematocrit effects, blood effects, and analyte stability. A third part of the review is dedicated to sample preparation and will consider off-line and on-line extractions; in particular, instrumental designs that have been developed so far for DBS extraction will be detailed. Flow injection analysis and applications will be discussed in section IV. The application of surface analysis mass spectrometry (DESI, paper spray, DART, APTDCI, MALDI, LDTD-APCI, and ICP) to DBS is described in section V, while applications based on separation techniques (e.g., liquid or gas chromatography) are presented in section VI. To conclude this review, the current status of DBS analysis is summarized, and future perspectives are provided.

Neonatal mass screening for 21-hydroxylase deficiency

Congenital adrenal hyperplasia(CAH)due to 21-hydroxylase deficiency (21-OHD) is an inherited autosomal recessive disorder. Its incidence is 1 in 10,000 to 20,000 worldwide. This disease shows phenotypic differences, and it is divided into three forms i.e., the salt wasting (SW), simple virilizing (SV), and nonclassic (NC) forms. The most severe form of SW manifests in the first months of life with life-threatening adrenal insufficiency, leading to death. To prevent death by adrenal insufficiency in neonates with the SW form and wrong gender assignment of 46,XX female patients with SW and SV, neonatal mass screening of 21-OHD is performed in several countries including Japan. However, the positive predictive value (PPV) remains low, especially in preterm infants. To reduce the false positive rate and increase the PPV, liquid chromatography followed by tandem mass spectrometry (LC-MS/MS) as a second-tier test may be useful. In this review, the current knowledge on neonatal mass screening of 21-OHD is summarized.

Expanded newborn screening by mass spectrometry: New tests, future perspectives

Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs.

The next 150 years of congenital adrenal hyperplasia

Congenital adrenal hyperplasias (CAH) are a group of autosomal recessive defects in cortisol biosynthesis. Substantial progress has been made since the description of the first report, 150 years ago. This article reviews some of the recent advances in the genetics, diagnosis and treatment of CAH. In addition, we underline the aspects where further progress is required, including, among others, better diagnostic modalities for the mild phenotype and for some of the rare forms of disease, elucidation of epigenetic factors that lead to different phenotypes in patients with identical genotype and expending on treatment options for controlling the adrenal androgen excess.

Mass spectrometry and immunoassay: how to measure steroid hormones today and tomorrow

The recent onslaught of mass spectrometry (MS) to measurements of steroid hormones, including demands that they should be the only acceptable method, has confused clinicians and scientists who have relied for more than 40 years on a variety of immunoassay (IA) methods in steroid hormone measurements. There is little doubt that MS methods with their superior specificity will be the future method of choice in many clinical and research applications of steroid hormone measurement. However, the majority of steroid measurements are currently, and will continue to be, carried out using various types of IAs for several reasons, including their technical ease, cost and availability of commercial reagents. Speedy replacement of all IAs with MS is an unrealistic and unnecessary goal, because the availability of MS measurements is limited by cost, need of expensive equipment, technical demands and lack of commercial applications. Furthermore, IAs have multiple well-known advantages that vindicate their continuing use. The purpose of this article is to elucidate the advantages and limitations of the MS and IA techniques from two angles, i.e. promotion of MS and defence of IA. The purpose of the text is to give the reader an unbiased view about the current state and future trends of steroid analysis and to help him/her choose the correct assay method to serve his/her diagnostic and research needs.

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.

Therapy monitoring in congenital adrenal hyperplasia by dried blood samples

Careful monitoring of the therapy is crucial for patients with congenital adrenal hyperplasia (CAH) in order to prevent the effects of increased androgen production as well as life-threatening salt-wasting crisis. The key metabolite, 17α-hydroxyprogesterone (17-OHP) can be detected in serum, saliva or dried blood. In clinical practice there are challenges due to discomfort of venous blood sampling and complicated retrieval of saliva during infancy. Furthermore, the immunoassay method is limited in its specificity due to cross-reactions. In this observational study we prospectively examined over a period of 5 years, 20 patients with CAH due to 21-hydroxylase deficiency using standard immunoassays for serum samples (radioimmunoassay and enzyme immunoassay) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in dried blood spots. Bland-Altman plots show goodness of agreement between both the methods for the desirable therapeutic concentration range of 17-OHP. LC-MS/MS is characterized by a high accuracy in the therapeutic concentration range of 17-OHP <100 nmol/L (r=0.91). Dried blood samples are convenient and reliable specimen for 17-OHP measured by LC-MS/MS. This method could be used for home monitoring of hydrocortisone replacement therapy both in salt-waster and simple virilizer CAH.

Adrenal steroidogenesis and congenital adrenal hyperplasia

Adrenal steroidogenesis is a dynamic process, reliant on de novo synthesis from cholesterol, under the stimulation of ACTH and other regulators. The syntheses of mineralocorticoids (primarily aldosterone), glucocorticoids (primarily cortisol), and adrenal androgens (primarily dehydroepiandrosterone and its sulfate) occur in separate adrenal cortical zones, each expressing specific enzymes. Congenital adrenal hyperplasia (CAH) encompasses a group of autosomal-recessive enzymatic defects in cortisol biosynthesis. 21-Hydroxylase (21OHD) deficiency accounts for more than 90% of CAH cases and, when milder or nonclassic forms are included, 21OHD is one of the most common genetic diseases.

Newborn screening for congenital adrenal hyperplasia in New Zealand, 1994-2013

OBJECTIVE

The objective of the study was to evaluate the efficacy of national newborn screening for severe congenital adrenal hyperplasia (CAH) in New Zealand over the past 20 years.

METHODS

Newborn screening for CAH is performed through the estimation of 17-hydroxyprogesterone by a Delfia immunoassay. CAH cases diagnosed in the newborn period from 1994 to 2013 were identified from Newborn Metabolic Screening Programme records.

RESULTS

Between 1994 and 2013, 44 neonates (28 females, 16 males) were diagnosed with CAH, giving an incidence of 1:26 727. Almost half (n = 21) of the newborns with CAH were detected solely via screening (not clinically suspected), including 21% of all affected females. Among the group solely ascertained by screening, 17-hydroxyprogesterone sampling occurred at a mean age of 3.3 days (range 2-8 d), the duration from sampling to notification was 5.2 days (0-12 d), and treatment was initiated at 12.0 days (6-122 d). Vomiting was present in 14% of those ascertained by screening, but none had hypotension or collapse at diagnosis. Increasing age at treatment was correlated with a progressive decrease in serum sodium (r = -0.56; P < .0001) and an increase in serum potassium concentrations (r = 0.38; P = .017). Compared with newborns diagnosed by screening alone, those clinically diagnosed were predominantly female (96% vs 29%; P < .0001), notification occurred earlier (4.8 vs 8.5 d; P = .002), and had higher serum sodium (136.8 vs 130.8 mmol/L; P < .0001) and lower serum potassium (5.3 vs 6.0 mmol/L; P = .011) concentrations.

CONCLUSIONS

Screening alone accounted for nearly 50% cases of CAH detected in the newborn period, including a fifth of affected females, indicating that clinical diagnosis is unreliable in both genders. Symptoms were mild at diagnosis and there were no adrenal crises. This study confirms the benefits of newborn CAH screening.

Newborn screening for medium chain acyl-CoA dehydrogenase deficiency: performance improvement by monitoring a new ratio

Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is a fatty acid oxidation disorder included on newborn screening (NBS) panels in many regions that have expanded to using tandem mass spectrometry for acylcarnitine screening. False positive (FP) screening results for MCAD deficiency have previously been linked to very low birth weight (VLBW) infants and those who are heterozygous for the common mutation, p.K324E. Previous studies have identified these causes of FP screens by sequencing residual dried blood spots. From our cohort of FP screens in Georgia, we identified an elevation at the same mass as octenoylcarnitine (C8:1) causing elevations of octanoylcarnitine (C8) not due to MCAD deficiency. We reviewed biochemical results from 2011 to 2013 for all newborn screens positive for MCAD deficiency in Georgia to identify screening criteria to allow these cases to be identified prospectively, thus saving families the stress of additional testing on their newborn and reducing healthcare costs while improving screening performance for the screening program. We identified the C8/C8:1 ratio as an effective marker, and developed criteria that will reduce FP screening results due to this interfering substance.

Novel method to characterize CYP21A2 in Florida patients with congenital adrenal hyperplasia and commercially available cell lines

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder and affects approximately 1 in 15,000 births in the United States. CAH is one of the disorders included on the Newborn Screening (NBS) Recommended Uniform Screening Panel. The commonly used immunological NBS test is associated with a high false positive rate and there is interest in developing second-tier assays to increase screening specificity. Approximately 90% of the classic forms of CAH, salt-wasting and simple virilizing, are due to mutations in the CYP21A2 gene. These include single nucleotide changes, insertions, deletions, as well as chimeric genes involving CYP21A2 and its highly homologous pseudogene CYP21A1P. A novel loci-specific PCR approach was developed to individually amplify the CYP21A2 gene, the nearby CYP21A1P pseudogene, as well as any 30 kb deletion and gene conversion mutations, if present, as single separate amplicons. Using commercially available CAH positive specimens and 14 families with an affected CAH proband, the single long-range amplicon approach demonstrated higher specificity as compared to previously published methods.

Inborn errors of metabolism and expanded newborn screening: review and update

Inborn errors of metabolism (IEM) are a phenotypically and genetically heterogeneous group of disorders caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites. To date, more than 1000 different IEM have been identified. While individually rare, the cumulative incidence has been shown to be upwards of 1 in 800. Clinical presentations are protean, complicating diagnostic pathways. IEM are present in all ethnic groups and across every age. Some IEM are amenable to treatment, with promising outcomes. However, high clinical suspicion alone is not sufficient to reduce morbidities and mortalities. In the last decade, due to the advent of tandem mass spectrometry, expanded newborn screening (NBS) has become a mandatory public health strategy in most developed and developing countries. The technology allows inexpensive simultaneous detection of more than 30 different metabolic disorders in one single blood spot specimen at a cost of about USD 10 per baby, with commendable analytical accuracy and precision. The sensitivity and specificity of this method can be up to 99% and 99.995%, respectively, for most amino acid disorders, organic acidemias, and fatty acid oxidation defects. Cost-effectiveness studies have confirmed that the savings achieved through the use of expanded NBS programs are significantly greater than the costs of implementation. The adverse effects of false positive results are negligible in view of the economic health benefits generated by expanded NBS and these could be minimized through increased education, better communication, and improved technologies. Local screening agencies should be given the autonomy to develop their screening programs in order to keep pace with international advancements. The development of biochemical genetics is closely linked with expanded NBS. With ongoing advancements in nanotechnology and molecular genomics, the field of biochemical genetics is still expanding rapidly. The potential of tandem mass spectrometry is extending to cover more disorders. Indeed, the use of genetic markers in T-cell receptor excision circles for severe combined immunodeficiency is one promising example. NBS represents the highest volume of genetic testing. It is more than a test and it warrants systematic healthcare service delivery across the pre-analytical, analytical, and post-analytical phases. There should be a comprehensive reporting system entailing genetic counselling as well as short-term and long-term follow-up. It is essential to integrate existing clinical IEM services with the expanded NBS program to enable close communication between the laboratory, clinicians, and allied health parties. In this review, we will discuss the history of IEM, its clinical presentations in children and adult patients, and its incidence among different ethnicities; the history and recent expansion of NBS, its cost-effectiveness, associated pros and cons, and the ethical issues that can arise; the analytical aspects of tandem mass spectrometry and post-analytical perspectives regarding result interpretation.

No evidence of an increase in early infant mortality from congenital adrenal hyperplasia in the absence of screening

OBJECTIVE

Congenital adrenal hyperplasia (CAH) is not currently included in the UK newborn screening programme. We investigated the hypothesis that, owing to non-specificity of symptoms, a proportion of males affected by salt-wasting (SW) CAH have died in infancy without being diagnosed.

DESIGN

Stored newborn screening blood spot samples were analysed for 17α-hydroxyprogesterone (17-OHP) in the following groups: Infants born in the North West of England, 1994 to 2006, who had died by 6 months age; (n=1198), a neonatal reference group (full-term n=100; preterm n=100) and a CAH positive control group. A newborn blood spot sample collected before diagnosis was available in 29/61 CAH patients recruited. SW CAH was present in 18/29 patients (16 males and 2 females). Samples from the deceased group with elevated 17-OHP were analysed for 8 common mutations in the 21-hydroxylase gene (CYP21A2).

SETTING

North West of England.

RESULTS

Grouped by gestational age, mean (maximum) blood spot 17-OHP in nmol/L was as follows. Deceased full-term n=279, 6 (107); deceased premature n=365, 28 (251); deceased unknown gestational age n=553, 13 (>394). In the SW positive control group, the lowest level of 17-OHP was 179 nmol/L and 14 had levels greater than the highest standard (>268 to >420 nmol/L). All samples from the deceased group with 17-OHP results >179 nmol/L (n=6) and a further 13 samples underwent mutation analysis. No mutations were identified.

CONCLUSIONS

Our findings do not support the hypothesis that, in our unscreened population, males affected by SW CAH are dying prior to diagnosis.

Steroid profiling for congenital adrenal hyperplasia by tandem mass spectrometry as a second-tier test reduces follow-up burdens in a tertiary care hospital: a retrospective and prospective evaluation

BACKGROUND

Newborn screening for congenital adrenal hyperplasia (CAH) based on measuring 17-hydroxyprogesterone (17-OHP) by immunoassay generates a number of false-positive results, especially in preterm neonates. We applied steroid profiling by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a second-tier test in newborns with positive CAH screening and evaluated its clinical utility in a tertiary care hospital setting.

METHODS

By performing a 4-year retrospective data review, we were able to test 121 dried blood spots from newborns with positive CAH screening for 17-OHP, androstenedione and cortisol levels by LC-MS/MS. We prospectively evaluated the clinical utility of steroid profiling after the implementation of steroid profiling as a second-tier test in our routine clinical practice. During the 2-year prospective study period, 104 cases with positive initial screening by FIA were tested by LC-MS/MS. Clinical and laboratory follow-up were performed for at least 6 months.

RESULTS

The preterm neonates accounted for 50.7% (76/150) and 70.4% (88/125) of screening-positive cases in retrospective and prospective cohorts, respectively. By applying steroid profiling as a second-tier test for positive CAH screening, we eliminated all false-positive results and decreased the median follow-up time from 75 to 8 days.

CONCLUSIONS

Our data showed that steroid profiling reduced the burden of follow-up exams by improving the positive predictive value of the CAH screening program. The use of steroid profiling as a second-tier test for positive CAH screening will improve clinical practice particularly in a tertiary care hospital setting where positive CAH screening from preterm neonates is frequently encountered.