Newborn Screening and Diagnosis of Infants with Congenital Adrenal Hyperplasia

High carrier frequency of CYP21A2 gene mutations in Southern India - underscoring the need for genetic testing in Congenital Adrenal Hyperplasia

PURPOSE

Congenital Adrenal Hyperplasia (CAH) is one of the highly prevalent autosomal recessive endocrine disorders. The majority of CAH cases result from mutations in the CYP21A2 gene, leading to 21-hydroxylase deficiency. However, with the pseudogene-associated challenges in CYP21A2 gene analysis, routine genetic diagnostics and carrier screening in CAH are not a part of the first-tier investigations in a clinical setting. Furthermore, there is a lack of data on the carrier frequency for 21-OH deficiency. Therefore, this study is aimed at investigating the carrier frequency of common pseudogene derived CYP21A2 mutations in Southern India.

METHODS

Recently, a cost-effective Allele-specific PCR based genotyping for CYP21A2 hotspot mutations has been demonstrated to be a highly specific and sensitive assay at the authors' center. Leveraging this approach, a total of 1034 healthy individuals from South India underwent screening to identify the carrier frequency of nine hotspot mutations in the CYP21A2 gene.

RESULTS

In this study, it was observed that 9.76% of the subjects were carriers for one or more of the nine different CYP21A2 mutations. Among the carriers, the most common was the large 30 kb deletion, followed by II72N, E6 CLUS, and I2G mutations.

CONCLUSION

We have identified a high prevalence of CYP21A2 mutation carriers in Southern India. These findings emphasize the importance of implementing and expanding cost-effective genetic diagnostics and carrier screening throughout India. Such initiatives would play a crucial role in managing the disease burden, enabling early intervention, and establishing guidelines for CAH newborn genetic screening in the country. This study represents the first carrier screening data on CYP21A2 hotspot mutations from India and is the largest study conducted till date in this context.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Congenital Adrenal Hyperplasia - A Comprehensive Review of Genetic Studies on 21-Hydroxylase Deficiency from India

Congenital adrenal hyperplasia (CAH) comprises a heterogeneous group of autosomal recessive disorders impairing adrenal steroidogenesis. Most cases are caused by mutations in the CYP21A2 gene resulting in 21-hydroxylase (21-OH) deficiency (21-OHD). The genetics of 21-OH CAH is complexed by a highly homologous pseudogene CYP21A1P imposing several limitations in the molecular analysis. Therefore, genetic testing is still not a part of routine CAH diagnosis and is mainly dependent on 17-hydroxy progesterone (OHP) measurements. There are very few reports of CYP21A2 gene analysis from India and there is no comprehensive review available on genetic testing and the spectrum of CYP21A2 mutations from the country. This review focuses on the molecular aspects of 21-OHD and the genetic studies on CYP21A2 gene reported from India. The results of these studies insist the compelling need for large-scale CYP21A2 genetic testing and newborn screening (NBS) in India. With a high disease prevalence and consanguinity rates, robust and cost-effective genetic testing for 21-OH CAH would enable an accurate diagnosis in routine clinical practice. Whereas establishing affordable genotyping assays even in secondary care or resource-poor settings of the country can identify 90% of the mutations that are pseudogene derived, initiatives on reference laboratories for CAH across the nation with comprehensive genetic testing facilities will be beneficial in those requiring extended analysis of CYP21A2 gene. Further to this, incorporating genetic testing in NBS and carrier screening programmes will enable early diagnosis, better risk assessment and community-based management.

[A promising approach for therapy control in congenital adrenal hyperplasia. Problems of Endocrinology]

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders requiring lifelong glucocorticoid replacement (GC) therapy. Lack of GC therapy leads to precocious puberty in boys, heterosexual development in girls, accelerated bone maturation and short final height in both sexes. In adolescence, the lack of GC therapy is the cause of menstrual disorders in girls and the development of TART in boys, as a result reducing the reproductive potential in both sexes. On the other hand, an overdose of GC leads to drug-induced Itsenko-Cushing's syndrome. In order to select adequate doses of GC in childhood and adolescence, multiple determinations of 17-hydroxyprogesterone, androstenedione, and testosterone in blood plasma, and thus multiple venous blood sampling are required. The blood sampling requires specially trained medical staff and can effect on the results due to stress reaction especially in young patients. Hence, the development and implementation of a non-invasive method for determining the steroid profile is extremely important in monitoring GC therapy in children. In addition, the currently used immunofluorescence assay cannot determine other adrenal steroids, has a high variation due to the «cross-reaction» of steroids that are similar in structure, which inflates the results. Unlike immunofluorescence assay, liquid chromatography and tandem mass spectrometry is more preferable method, since it is more specific and accurate. In this literature review, saliva presented as an alternative substrate and the non-invasive method for determining the steroid profile. This method can solve the above disadvantages, simplify and make more accurate the selection of GC therapy in patients with CAH, which is especially important in childhood.

An Approach to Re-evaluate the Reference Cutoff of the Parameters of Newborn Screening: An Observational Study

Background Unless a cutoff level of the parameters of newborn screening (NBS) is defined, a screening test's results would end in high recall rates and apprehensive parents. The study aimed to establish a cutoff level of the healthy term newborns. Materials and methods The study was a retrospective observational data analysis on a cohort of 1158 term newborns who underwent NBS in our institute. The percentile distribution of the NBS parameters was computed and the 99th percentile value was considered the new cutoff. For lower values, such as neonatal glucose 6-phosphate dehydrogenase (nG6PD) and neonatal biotinidase (nBIOT), low percentile values were regarded as new cutoff value. Results Neonatal thyroid stimulating hormone (nTSH), nG6PD, neonatal immunoreactive trypsinogen (nIRT), and nBIOT showed a wide variation in the distribution. Most newborns had neonatal galactose (nGAL), nIRT, and nBIOT values above the median. The 99th percentile value of nTSH was 14.5 mIU/L, and that of neonatal 17-hydroxyprogesterone (n17-OHP) was 43.7 nmol/L. The 1.0th percentile value for nG6PD was decreased to 2.18 IU/gHb. The new cutoff values for nBIOT, nIRT, neonatal phenylketonuria (nPKU) and nGAL were 48.59 U, 95.3 µg/L, 2.3 mg/dL and 15.9 mg/dL. The mean and median nTSH values did not significantly differ (p=0.99) in the first five days of birth. On the contrary, the study population depicted considerably raised levels of n17-OHP on day 3, followed by a sharp decrease (p=0.029). Similarly, nIRT displayed significant differences in the first five days (p=0.017). Conclusion Using the 99th percentile values of the NBS parameters as the new cutoff levels might be beneficial in terms of the recall rates and cost burden.

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.

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Method for the Quantification of Steroids Androstenedione, Dehydroepiandrosterone, 11-Deoxycortisol, 17-Hydroxyprogesterone, and Testosterone

Congenital adrenal hyperplasia (CAH) is a group of autosomal-recessive disorders due to deficiency of 11- or 21-hydroxylase. The analysis of cortisol, androstenedione, 17-hydroxyprogesterone (OHPG), dehydroepiandrosterone (DHEA), 11-deoxycortisol, and testosterone is generally performed in the diagnosis and/or follow-up of CAH. Analysis of specific steroids is also performed in other disorders such as evaluation of hirsutism or infertility in females and hypogonadism in males. Cortisol is generally analyzed by immunoassays, whereas other hormones are preferably assayed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A multiple reaction monitoring, positive mode atmospheric pressure chemical ionization, LC-MS/MS method is described for the simultaneous quantification of androstenedione, 17-hydroxyprogesterone, DHEA, 11-deoxycortisol and testosterone. The method involves addition of labeled internal standards to serum samples and extraction of steroids in methyl tert-butyl ether. The extract is evaporated under stream of nitrogen, and the residue is reconstituted in methanol and analyzed by LC-MS/MS.

Approach of Heterogeneous Spectrum Involving 3beta-Hydroxysteroid Dehydrogenase 2 Deficiency

We aim to review data on 3beta-hydroxysteroid dehydrogenase type II (3βHSD2) deficiency. We identified 30 studies within the last decade on PubMed: 1 longitudinal study (N = 14), 2 cross-sectional studies, 1 retrospective study (N = 16), and 26 case reports (total: 98 individuals). Regarding geographic area: Algeria (N = 14), Turkey (N = 31), China (2 case reports), Morocco (2 sisters), Anatolia (6 cases), and Italy (N = 1). Patients’ age varied from first days of life to puberty; the oldest was of 34 y. Majority forms displayed were salt-wasting (SW); some associated disorders of sexual development (DSD) were attendant also—mostly 46,XY males and mild virilisation in some 46,XX females. SW pushed forward an early diagnosis due to severity of SW crisis. The clinical spectrum goes to: premature puberty (80%); 9 with testicular adrenal rest tumours (TARTs); one female with ovarian adrenal rest tumours (OARTs), and some cases with adrenal hyperplasia; cardio-metabolic complications, including iatrogenic Cushing’ syndrome. More incidental (unusual) associations include: 1 subject with Barter syndrome, 1 Addison’s disease, 2 subjects of Klinefelter syndrome (47,XXY/46,XX, respective 47,XXY). Neonatal screening for 21OHD was the scenario of detection in some cases; 17OHP might be elevated due to peripheral production (pitfall for misdiagnosis of 21OHD). An ACTH stimulation test was used in 2 studies. Liquid chromatography tandem–mass spectrometry unequivocally sustains the diagnostic by expressing high baseline 17OH-pregnenolone to cortisol ratio as well as 11-oxyandrogen levels. HSD3B2 gene sequencing was provided in 26 articles; around 20 mutations were described as “novel pathogenic mutation” (frameshift, missense or nonsense); many subjects had a consanguineous background. The current COVID-19 pandemic showed that CAH-associated chronic adrenal insufficiency is at higher risk. Non-adherence to hormonal replacement contributed to TARTs growth, thus making them surgery candidates. To our knowledge, this is the largest study on published cases strictly concerning 3βHSD2 deficiency according to our methodology. Adequate case management underlines the recent shift from evidence-based medicine to individualized (patient-oriented) medicine, this approach being particularly applicable in this exceptional and challenging disorder.

Allele-specific PCR and Next-generation sequencing based genetic screening for Congenital Adrenal Hyperplasia in India

Genetic screening of Congenital Adrenal Hyperplasia (CAH) is known to be challenging due to the complexities in CYP21A2 genotyping and has not been the first-tier diagnostic tool in routine clinical practice. Also, with the advent of massive parallel sequencing technology, there is a need for investigating its utility in screening extended panel of genes implicated in CAH. In this study, we have established and utilized an Allele-Specific Polymerase Chain Reaction (ASPCR) based approach for screening eight common mutations in CYP21A2 gene followed by targeted Next Generation Sequencing (NGS) of CYP21A2, CYP11B1, CYP17A1, POR, and CYP19A1 genes in 72 clinically diagnosed CAH subjects from India. Through these investigations, 88.7% of the subjects with 21 hydroxylase deficiency were positive for eight CYP21A2 mutations with ASPCR. The targeted NGS assay was sensitive to pick up all the mutations identified by ASPCR. Utilizing NGS in subjects negative for ASPCR, five study subjects were homozygous positive for other CYP21A2 variants: one with a novel c.1274G>T, three with c.1451G>C and one with c.143A>G variant. One subject was compound heterozygous for c.955C>T and c.1042G>A variants identified using ASPCR and NGS. One subject suspected for a Simple Virilizing (SV) 21 hydroxylase deficiency was positive for a CYP19A1:c.1142A>T variant. CYP11B1 variants (c.1201-1G>A, c.1200+1del, c.412C>T, c.1024C>T, c.1012dup, c.623G>A) were identified in all six subjects suspected for 11 beta-hydroxylase deficiency. The overall mutation positivity was 97.2%. Our results suggest that ASPCR followed by targeted NGS is a cost-effective and comprehensive strategy for screening common CYP21A2 mutations and the CAH panel of genes in a clinical setting.

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.

[Genital abnormalities: Contextualization of a neglected area in prenatal diagnosis]

OBJECTIVE

To reflect on how the area of genital abnormalities has fallen behind in prenatal diagnosis.

METHODS

Based on the thesis that prenatal diagnosis of genital abnormalities has scarcely developed, a comparison with other areas of prenatal diagnosis and with its postnatal counterpart is presented; different explanations for this situation are examined; and a reflection is presented on ways to expand this field of knowledge.

CONCLUSIONS

Compared to other disciplines, prenatal diagnosis of genital abnormalities finds itself lagging behind in terms of diagnostic tools, management protocols and scientific literature. Potential causes include a perception of low prevalence and limited importance, or exploration challenges. Integration of current knowledge, together with the acquisition of the appropriate tools and translation to clinical medicine, would be a way to make this discipline stronger.

CAH Newborn Screening in India: Challenges and Opportunities

Congenital adrenal hyperplasia (CAH) is a common treatable disorder which is associated with life-threatening adrenal crisis, sexual ambiguity, and/or abnormal growth if undiagnosed. Newborn screening is a cost-effective tool to detect affected babies early after birth to optimize their treatment and follow-up. Newborn screening however is in its nascent stage in India where it is not yet introduced universally for all babies. The following review briefly highlights the challenges (e.g., lack of universal screening, healthcare resources) and opportunities (e.g., reduction in morbidity and early correct gender assignment in females) associated with newborn screening for CAH in a large Indian birth cohort.