The Indian Journal of Pediatrics https://doi.org/10.1007/s12098-018-2645-9
ORIGINAL ARTICLE
Newborn Screening for Congenital Hypothyroidism and Congenital Adrenal Hyperplasia ICMR Task Force on Inherited Metabolic Disorders
Received: 5 March 2017 / Accepted: 13 February 2018 # Dr. K C Chaudhuri Foundation 2018
Abstract Objective The Task Force formed by ICMR aimed at studying the prevalence of congenital hypothyroidism and congenital adrenal hyperplasia, the template disorders included in all newborn screening programs, and to evaluate the unidentified challenges in its execution in health care services. It also intended to evaluate the feasibility of newborn screening with regards to different geo-ethnic regions from India. Methods Five metropolitan centers identified had further 2 to 11 centers; both the urban and the rural sectors were included and were considered representative of the northern, southern, eastern, western and central parts of the country. A uniform protocol was developed to screen 100,000 neonates (20,000 from each center) beyond 34 wk of gestation for congenital hypothyroidism and congenital adrenal hyperplasia. Samples were collected by heel prick after 24 h of age. The parameters studied were prevalence of these diseases, percentage births covered, the turnaround time, recall rate and follow up of identified neonates as feasibility indicators. All centers participated in the Newborn Screening Quality Assurance Programme (NSQAP), of CDC, Atlanta, USA. Results In the participating hospitals attached to the centers, 151,765 babies were intramural births. Of these 143,344 (94.5%) babies were eligible for screening. Amongst these births, a sample of 104,094 (73.2%) babies could be covered by the personnel. Overall prevalence of congenital hypothyroidism (CH) was 1 in 722 births; if babies with transient hypothyroidisms were excluded the prevalence was calculated to be 1:1130. The collective prevalence of congenital adrenal hyperplasia was 1 in 5762 with marked regional differences. Conclusions This collaborative study has demonstrated the feasibility of establishing a network of committed laboratories and scientists for executing newborn screening. This is expected to have a potential impact on morbidity and mortality and therefore this should be immediately taken up in a national newborn screening program. Keywords Newborn screening . Congenital hypothyroidism . Congenital adrenal hyperplasia . India
Introduction Members of the ICMR Task Force contributed equally to the study (names arranged in an alphabetical order): Dr. Rita Christopher, NIMHANS, Bangalore, India; Dr. A. Radha Rama Devi, Rainbow Children Hospital & Sandor Life Sciences, Road No 3, Banjara Hills, Hyderabad, India; Dr. Madhulika Kabra, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India; Dr. Seema Kapoor, Maulana Azad Medical College, New Delhi 110002, India; Dr. Roli Mathur, Indian Council of Medical Research, New Delhi, India; Dr. Mamta Muranjan, KEM Hospital, Mumbai, India; Dr. Puneet K. Nigam, Vimta Laboratories, Hyderabad, India; Dr. R. M. Pandey, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India; Dr. Arun Singh, IPGMER, Kolkata, India; Dr. S. Suresh, MEDISCAN, Chennai, India * ICMR Task Force on Inherited Metabolic Disorders
[email protected]
Some states in India have nearly met the Millennium developmental goals specifically in terms of reduction of under 5 mortality and hence the attention has started moving to quality of life rather than survival (http://mospi.nic.in/sites/default/ files/publication_reports/mdg_2july15_1.pdf). Though the burden of communicable diseases still exists, it is the right time to address issues such as causes of preventable intellectual disability and unexplained mortality. Newborn screening has been perceived as a programme, with immense translational benefit, as it is a preventive program, aimed at reducing both morbidity and mortality. Disorders screened in the various newborn-screening programs vary
Indian J Pediatr
from country to country and among countries from state to state. Amongst disorders screened congenital hypothyroidism (CH) forms the template disorder, as it is the commonest cause of preventable intellectual disability. Congenital adrenal hyperplasia (CAH) contributes significantly to both morbidity and early death. Taking these into consideration, the Indian Council of Medical Research funded a multicenter study. These two disorders were decided upon after multiple brain storming discussions, and were based on a priori data on epidemiology of the diseases [1–3] using the guidelines laid down by Wilson and Jengner [4]. The study aimed at determining the prevalence of these disorders, and the unidentified challenges in its execution before this programme could be incorporated in the mainstream health care. It was also intended to evaluate the feasibility of newborn screening in different geo-ethnic regions of India. This communiqué presents a summary of this collaborative work.
Material and Methods The five centers identified for inclusion were Chennai, Delhi, Hyderabad, Kolkata and Mumbai and were coded alphabetically as 01 to 05 to represent both the urban and the rural sectors and were considered representative of the northern, southern, eastern, western and central parts of the country. A data coordinating, monitoring management and analysis unit was established in the Department of Biostatistics, All India Institute of Medical Sciences, New Delhi Central Coordination Unit was set up at the ICMR Headquarters for monitoring and coordination with the sites. A chairman and a steering committee of experts in the field with vast experience in conducting multi-institutional collaborative studies monitored the insight and intricacies. The study consisted of a phase of brainstorming, a preparatory phase, a phase of consolidation and a phase of summation. The preparatory phase, lasted from 29th March, 2007 through 1st April, 2009, and preceded the actual collection of data and analysis. Activities carried out in the preparatory phase were identification of disorders and technology, identification and sensitization of all the collaborators, preparation of a uniform standard operating manual, installation and qualification of the equipment, training of the personnel, and standardization of the pre-examination and examination processes. It also included the development of the standard treatment protocol, deciding the frequency of clinical and biochemical ascertainments, standard case record performa capable of delineating etiology and co-morbidities. The patient information sheet and consent form were prepared keeping in mind the vernacular of these cities and were translated in 7 languages and back translated into Hindi for validity. A number of training workshops were carried out which included data and
sample collection, laboratory technology and quality control in which all centers participated. The Quality Control Program was based on kit based QC, external QC, retained samples testing and External Quality Assessment (EQA) for dried blood spot tests from CDC (Centers for Disease Control and Prevention, Atlanta, USA). Identification of the extra human resource component was also carried out in the preparatory phase. During the preparatory phase advocacy material was prepared in the form of posters, which were poetic, but in the 7 languages that were familiar to the geo-ethnic regions where the screening was being conducted. A logo was designed which depicted the map of India with dots representing analytical centers for newborn screening and high-risk analysis. The patient information sheet, which also had the consent form, was translated into 7 vernacular languages and back translated for validation. The sampling was carried out on the S & S 903 paper cards, air dried on a self designed drier made of heavy paper and transported manually to the testing laboratory. The laboratory tests were run twice a week and all presumptive positives were called back. The timing of collection was decided initially as 48 h to 7 d but later reduced to 24 h before the commencement of the phase of consolidation. This ensured collection in hospitals with high birthing rates. The demographic entry points were discussed and coded for ease of detailing and a similar entry template designed in the data-coordinating center to minimize manual errors. The data was transmitted every fortnight to the data-coordinating center in the form of an e-entry. The cards with demographics were having three self inking copies with one copy remaining at the birthing facility, other going to the testing laboratory and the final copy to the data coordinating center. The hard copy was tallied with the e-copy for consistence. Quantitative determination of thyroid stimulating hormone (TSH) was carried out on dried blood spots by DELFIA Neonatal TSH time resolved fluroimmunoassay from Perkin Elmer (Turku, Finland). The solid-phase, two-site fluoroimmunometric assay is based (neonatal hTSH) on the direct sandwich technique. Values up to 10 μU/mL of blood were taken as normal, values between 10-20μU/mL were considered ambiguous and those above 20 μU/mL were labeled as presumptive positive. The sensitivity of the TSH assay was 2 μU/mL whole blood units (4.44 μU/mL serum units). One-tenth of the samples were re-analyzed utilizing a different blood spot i.e., repunching from a new spot and confirmation to exclude analytical errors. All patients in the ambiguous zone and all presumptive positive patients were recalled. All recalled neonates were subjected to determination of Free unbound Thyroxine (FT3), Free triodothyronine (FT4) and TSH in serum using another technology available in the
Indian J Pediatr
participating institution (chemiluminesence to radioimmunoassay). They were further subjected to X-ray of the knee joint for determination of skeletal age and a radionuclide Technetium scan to delineate the thyroid gland. With these investigations the neonate was grouped into one of 4 categories. In neonates where gland could not be identified were qualified as agenesis, in those where it was aberrantly located Bectopic^, in those with poor function, hypoplastic gland and in those with good uptake but low FT3 as dyshormonogenesis. These neonates were followed up based on a uniform protocol, which included determination of the developmental quotient on uniform scales of assessment and plotting of the growth velocity. It was planned that they would be reassessed for permanence at 3 y of age after stopping L-Thyroxin for 4 wk. Estimation 17 α- hydoxy– Progesterone (17 α-OHP) was carried out on dried blood spot using 17 α-OH-Progesterone time resolved fluroimmunoassay kit of Perkin Elmer. The solid-phase, two-site fluoroimmunometric assay is based on the direct sandwich technique. Values upto 37.5 nmol/L of blood (12.37 ng/mL of Blood are equivalent to 27.375 ng/ml of Serum) were reported as normal, ambiguous were those values between 37.5 and 90 nmol/L and those above 90 nmol/L were labeled as presumptive positive. The eligibility was defined by a gestational age of 34 wk, adjusting of values for gestation was not required. For all neonates presumptive positive for CAH, 17α-OHP estimation was done on serum, using chemiluminescence technology. These neonates were further followed up for evaluating of salt wasting by measuring serum sodium, potassium and measuring the blood pressure. These neonates were further sub-classified as salt wasting type and the simple virilizing type.
Quality Control All participating labs ran the quality control samples, as prescribed by the manufacturer in each batch. At minimum, quality control samples with high and low reference values were run in all batches. The results of the batch were accepted only when the control values were within the specified range. Levey Jennings charts were plotted for acceptance and reviewing trends. Also, labs participated in additional interlab and intra-lab QC procedures. A random 10% of normal samples were retested to identify false negatives if any. Each lab verified accuracy of test results by participating in the Newborn Screening Quality Assurance Programme (NSQAP), of CDC, Atlanta, USA. This involved analyzing proficiency test samples periodically (blind samples) and reporting results online and being evaluated at global level. This is the oldest PT program in newborn screening based on dried blood spots, covering more than 35 countries. One of the most important achievements of the project was that all the participating labs achieved success in the PT program consistently, demonstrating that with planning and effective training,
a network of labs can be established meeting international standards in quality in the domain of newborn screening. One of the laboratories also successfully completed accreditation under ISO 15189:2007.
Results In the participating hospitals 151,765 deliveries took place. Of these 143,344 (94.5%) babies were eligible for screening. Those not eligible included neonates
