Challenges in translating metabolomic screening into clinical practice

Even though lysosomal storage disorders (LSDs) are considered to be orphan diseases, they pose a highly relevant cause for morbidity and mortality as their cumulative prevalence is estimated to be 1:4,000. This is especially important as treatment in form of enzyme replacement therapy, substrate reduction therapy or stem cell transplantation is amenable for some LSDs. It is plausible that an early start of treatment might improve the overall prognosis and, even more important, prevent irreversible damage of key organs. To get a more precise insight into the real frequency of some LSDs in the general population, we screened 40,024 samples from the Hungarian newborn screening (NBS) program in Szeged for Fabry disease (FD), Gaucher disease (GD), Pompe disease (PD), and Niemann-Pick A/B (NPB) disease using tandem mass spectrometry. Altogether, 663 samples (1.66%) were submitted for retesting. Genetic confirmation was carried out for 120 samples with abnormal screening results after retesting, which identified three cases of GD, three cases of FD, nine cases of PD, and two cases with NPB. In some cases, we detected up to now unknown mutations - one in NPB and seven in PD - which raise questions about the clinical consequences of a NBS in the sense of late-onset manifestations. Overall, we conclude that screening for LSDs by tandem MS/MS followed by a genetic workup in identified patients is a robust, easy, valid, and feasible technology in newborn screening programs. Furthermore, early diagnosis of LSDs gives a chance to early treatment, but needs more clinical long-term data especially regarding the consequence of private mutations.

Currently, the only metabolic disorder that newborns are screened for in Finland is congenital hypothyroidism. A proposal to start a pilot study on screening for other rare metabolic diseases using tandem mass spectrometry prompted a health technology assessment project on the effect and costs of expanded newborn screening programme options. A modelling study using data from current published studies, healthcare registers and expert opinion. The annual running cost of screening 56,000 newborns for the chosen five disorders (congenital adrenal hyperplasia, medium-chain acyl-CoA dehydrogenase deficiency [MCADD], long chain 3-hydroxyacyl-CoA dehydrogenase deficiency [LCHADD], phenylketonuria [PKU] and glutaric aciduria type 1 [GA 1]) was estimated to be euros 2.5 million or euros 45 per newborn when starting costs were included. The costs per quality-adjusted life year (QALY) gained are a maximum of euros 25,500. Prevention of severe handicap in one newborn would reduce the costs to a maximum of euros 18,000 per QALY gained. Expanding the Finnish neonatal screening programme would require a new organization. The cost-effectiveness, resources, ethics and equity need to be considered when deciding in favour of or against starting a new screening programme.

In search of the optimal therapy for congenital hypothyroidism

Since 2001, tandem mass spectrometry was introduced for newborn screening by two Taiwan national newborn screening centers: Taipei Institute of Pathology and Chinese Foundation of Health, in Taiwan, respectively. A total of 24 metabolic disorders, including 6 amino acidopathies, 8 organic acid disorders and 9 fatty acid disorders, etc., were screened and the newborns with positive screening result were referred to Taipei Veterans General Hospital for confirmatory diagnosis. Until Dec 2014, a total of 1,391,583 newborns have been screened by these two newborn screening centers. The overall incidence of inborn errors of metabolism identified by tandem mass was approximately 1/6,000. The most common inborn errors were defects of phenylalanine metabolism (phenylketonuria: 1/60,000; 6-pyruvoyltertrahydropterin synthase (PTPS): 1/110,000). Maple syrup urine disease was the second most common amino acidopathy (1/100,000) and, significantly, most MSUD patients (75%) belonged to the Austronesian aboriginal tribes of southern Taiwan. The most frequently detected organic acid disorder was 3-methylcrotonyl-CoA carboxylase deficiency (1/35,000). Glutaric aciduria type 1 and methylmalonic academia were the second most common organic acid disorders (1/100,000 for each disease). The incidence of fatty acid disorder is relatively less than most western countries. Out of them, carnitine transport defect was the most common fatty acid disease (1/100,000). In this report we will present this large population study of tandem mass newborn screening in Chinese population.

Inherited metabolic diseases are rare but may cause severe damages if not cared for in time.A neonatal screening program, including a first quick test to all newborns and a second accurate test for patients with positive results, is being planned in Veneto region, northeast Italy.A simulation model describing all operations has been built and implemented with the scope of giving suitable dimension to operating centres, in order to care for all revealed pathology within the maximum time before they may become dangerous for the involved patients.The model is pretty general and its application may be extended to changed situation of the same region or to other regions.

Newborn screening comprises a paramount public health program seeking timely detection, diagnosis, and intervention for genetic disorders that may otherwise produce serious clinical consequences. Today newborn screening is part of the health care system of developed countries, whereas in India, newborn screening is still in the toddler stage. We searched PubMed with the keywords newborn screening for metabolic disorders, newborn screening in India, and congenital disorder in neonates, and selected publications that seem appropriate. In India, in spite of the high birth rate and high frequency of metabolic disorders, newborn screening programs are not part of the health care system. At Union Territory, Chandigarh in 2007, newborn screening was initiated and is currently ongoing for three disorders, that is, congenital hypothyroidism, congenital adrenal hyperplasia, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Prevalence of these disorders is found to be 1:1400 for congenital hypothyroidism, 1:6334 for congenital adrenal hyperplasia, and 1:80 for G6PD deficiency. Mandatory newborn screening for congenital hypothyroidism should be implemented in India, and other disorders can be added in the screening panel on the basis of region-wise prevalence. The objective of this review is to provide insight toward present scenario of newborn screening in India along with recommendations to combat the hurdles in the pathway of mandatory newborn screening.

Outcome of the glutaric aciduria type 1 (GA1) newborn screening program in Manitoba: 1980–2020

Next generation sequencing as a follow-up test in an expanded newborn screening programme

Glutaric aciduria type 1(GA-1) is an inherited cerebral organic aciduria. Untreated patients with GA-1 have a risk of acute encephalopathic crises during the first 6 years of life. In so far as GA-1 desperately does not exist in Turkish newborn screening (NBS) program, most patients in our study were late-diagnosed. This study included 41 patients diagnosed with acylcarnitine profile, urinary organic acids, mutation analyses in the symptomatic period. We presented with clinical, neuroradiological, and molecular data of our 41 patients. The mean age at diagnosis was 14.8 ± 13.9 (15 days to 72 months) and, high blood glutaconic acid, glutarylcarnitine and urinary glutaric acid (GA) levels in 41 patients were revealed. Seventeen different mutations in the glutaryl-CoA dehydrogenase gene were identified, five of which were novel. The patients, most of whom were late-diagnosed, had a poor neurological outcome. Treatment strategies made a little improvement in dystonia and the frequency of encephalopathic attacks. All GA-1 patients in our study were severely affected since they were late-diagnosed, while others show that GA-1 is a treatable metabolic disorder if it is diagnosed with NBS. This study provides an essential perspective of the severe impact on GA-1 patients unless it is diagnosed with NBS. We immediately advocate GA-1 to be included in the Turkish NBS.

Presymptomatic detection of patients with rare diseases (RD), defined by a population frequency less than 1 : 2,000, is the task of newborn screening (NBS). In the Czech Republic (CZ), currently eighteen RD are screened: phenylketonuria/hyperphenylalaninemia (PKU/HPA), congenital hypothyroidism (CH), congenital adrenal hyperplasia (CAH), cystic fibrosis (CF), medium chain acyl-CoA dehydrogenase deficiency (MCADD), long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), very long chain acyl-CoA dehydrogenase deficiency (VLCADD), carnitine palmitoyl transferase I and II deficiency (CPTID, CPTIID), carnitine-acylcarnitine translocase deficiency (CACTD), maple syrup urine disease (MSUD), glutaric aciduria type I (GA I), isovaleryl-CoA dehydrogenase deficiency (IVA), argininemia (ARG), citrullinemia (CIT), biotinidase deficiency (BTD), cystathionine beta-synthase-deficient homocystinuria (CBSD HCU), and methylenetetrahydrofolate reductase deficiency homocystinuria (MTHFRD HCU). The aim was to analyze the prevalence of RD screened by NBS in CZ. We examined the NBS programme in CZ from 1 January 2010 to 31 December 2017, which covered 888,891 neonates. Dried blood spots were primarily analyzed using fluorescence immuno-assay, tandem mass spectrometry and fluorimetry. The overall prevalence of RD among the neonate cohort was 1 : 1,043. Individually, 1 : 2,877 for CH, 1 : 5,521 for PKU/HPA, 1 : 6,536 for CF (1 : 5,887 including false negative patients), 1 : 12,520 for CAH, 1 : 22,222 for MCADD, 1 : 80,808 for LCHADD, 1 : 177,778 for GA I, 1 : 177,778 for IVA, 1 : 222,223 for VLCADD, 1 : 296,297 for MSUD, 1 : 8,638 for BTD, and 1 : 181,396 for CBSD HCU. The observed prevalence of RD, based on NBS, corresponds to that expected, more precisely it was higher for BTD and lower for MSUD, IVA, CBSD HCU, MCADD and VLCADD. Early detection of rare diseases by means of NBS is an effective secondary prevention tool.

Objective For clinically understanding of glutaric acidemia type Ⅰ (GA-Ⅰ), the relationship of the clinical manifestations and the serum levels of free carnitine (C0), glutarylcarnitine (C5DC), and capryloylcarnitine (C8) as well as the urinary levels of glutaric acid and mevalonolactone of patients with GA-Ⅰ were studied. Methods From December 2007 to April 2016, a total of 62 patients with GA-Ⅰ (GA-Ⅰ group) and 62 healthy children (control group) were included. Tandem mass spectrometry was used to measure the blood levels of C0, C5DC, and C8, while, gas chromatography-mass spectrometry was used to measure the urine levels of glutaric acid and mevalonolactone. Results Total 62 cases, 36 males and 26 females, median age 1.2 years (range from 27 days to 9.3 years) were enrolled. Clinical features included macrocephaly, dyskinesia, seizures, growth and mental retardation, abnormal muscular tension, as well as feeding difficulties. The median levels of C5DC, C5DC/C8, glutaric acid, mevalonolactone were 0.90 μmol/L, 24.25, 936.30 mmol/mol creatinine, and 141.5 mmol/mol creatinine respectively, which were higher than those of the control group (all P<0.01). While the median level of C0 was between the reference value, and the median level of C8 was lower than the control group (0.04 vs 0.10 μmol/L). Cranial magnetic resonance image (MRI) had been carried out in 34 patients. Multiple and symmetrical abnormal signal in white matter and basal ganglia, widening of the sylvian fissure, expansion of cerebro-spinal fluid spaces anterior to the temporal lobes were cardinal signs of GA-Ⅰ. Conclusions Patients with GA-Ⅰ present with complex and variable clinical features, mainly including abnormal increase of head circumference, retarded motor and language development, repeated convulsions and characteristic abnormalities in brain MRI. Significant increase in the blood levels of C5DC and C5DC/C8 and in urine level of glutaricacid and mevalonolactonemay are specific to the diagnosis of GA-Ⅰ. For mild cases, repeated tests and genomic mutation analysis are necessary. (Chin J Endocrinol Metab, 2017, 33: 730-734) Key words: Glutaric acidemia Ⅰ; Glutarylcarnitine; Glutaric acid; Tandem mass spectrometry; Gas chromatography-mass spectrometry

Newborn blood spot screening programmes are designed to detect serious conditions affecting individuals, where early treatment can improve health. It is suggested that screening can improve the experience of diagnosis for parents. For example, without newborn screening, when a child with cystic fibrosis becomes symptomatic a period of uncertainty can arise prior to diagnosis. These potential advantages of screening need to be weighed against potential disadvantages of screening at individual and population levels. Some newborn screening programmes inadvertently identify newborn infants who, although not affected by the condition, carry a gene for it and can pass on that gene to their children; these are 'genetic carriers'. Knowledge of newborn carrier status can lead to: testing of parents and family members, and concern about possible affected future siblings should both parents be identified as carriers; the possibility of such testing revealing the putative father is not the biological father; concern about the child's future reproductive choices; and unjustified anxiety about the health of the carrier newborn. There is an urgent need to develop clear guidance as to how to respond, with advances in technology fuelling the expansion of newborn blood spot screening and raised expectations of informed consent and disclosing test results. Depending on the condition for which screening is offered, options include: employing tests that do not identify carrier status, if available; identifying acceptable ways of disclosing carrier status; or identifying acceptable ways of not disclosing carrier status. These options are illustrated by screening programmes for sickle cell disorders and cystic fibrosis. Currently, there are no screening tests available for sickle cell disorders that do not identify carrier status. For cystic fibrosis, the policy choice is between an extended period of testing, and a screening result that is available sooner for most newborns, but inadvertently identifies carrier babies. The aim of this review was to assess the impact of disclosing to parents newborn carrier status inadvertently identified by routine newborn blood spot screening. We searched for reports addressing disclosing newborn carrier status to parents following newborn screening for sickle cell disorders and cystic fibrosis in: commercially available electronic databases (October 2002), specialist registers, online journals, online abstracts and conference abstracts. We also scanned the reference lists of included papers. Studies addressing the impact of disclosing carrier status using a soundly controlled trial or randomised controlled trial. Two researchers independently scanned titles and abstracts for relevance using the pre-specified inclusion criteria. Full reports of selected citations were then located and screened again for relevance by two researchers independently. At each stage, results were compared and discrepancies resolved by discussion. We found no controlled trials about disclosing carrier status. There is a need to develop and evaluate the effects of interventions to support the disclosure of carrier status to parents following newborn screening.

Background and Objectives: The main reason for Newborn screening (NBS) for congenital adrenal hyperplasia (CAH) is to prevent adrenal insufficiency that can lead to life-threatening conditions. On the other hand, screening programs are not always sensitive and effective enough to detect the disease. We aimed to evaluate impact of the national NBS on the clinical presentation of patients with CAH in Lithuania. Materials and Methods: A retrospective study was performed on data of 88 patients with CAH from 1989 to 2020. Patients with confirmed CAH were divided into two groups: (1) 75 patients diagnosed before NBS: 52 cases with salt-wasting (SW), 21 with simple virilising (SV) and two with non-classical (NC) form; (2) 13 patients diagnosed with NBS: 12 cases with SW and 1 case with SV form. For the evaluation of NBS effectiveness, data of only male infants with salt-wasting CAH were analysed (n = 36, 25 unscreened and nine screened). Data on gestational age, birth weight, weight, symptoms, and laboratory tests (serum potassium and sodium levels) on the day of diagnosis, were analysed. Results: A total of 158,486 neonates were screened for CAH from 2015 to 2020 in Lithuania and CAH was confirmed in 13 patients (12 SW, one–SV form), no false negative cases were found. The sensitivity and specificity of NBS program for classical CAH forms were 100%; however, positive predictive value was only 4%. There were no significant differences between unscreened and screened male infant groups in terms of age at diagnosis, serum potassium, and serum sodium levels. Significant differences were found in weight at diagnosis between the groups (−1.67 ± 1.12 SDS versus 0.046 ± 1.01 SDS of unscreened and screened patients respectively, p = 0.001). Conclusions: The sensitivity and specificity of NBS for CAH program were 100%, but positive predictive value—only 4%. Weight loss was significantly lower and the weight SDS at diagnosis was significantly higher in the group of screened patients.

The newborn screening programme in Bavaria was confronted with several problems. Number of disorders and process quality no longer complied with screening guidelines. Mixed financing, distributed between the state (PKU, galactosaemia) and health insurances (hypothyroidism) had promoted an increasing dissipation of the system. Notified participation rates had dropped to < 80%. Increasing need for a second screening due to early discharge was an additional challenge. To overcome these problems, and considering the availability of improved screening methodology (tandem mass spectrometry) the programme was reorganised. The project, which started on Jan 1, 1999, is based on a cooperation model between laboratory (logistics, analysis), universities (treatment, scientific evaluation), and public health services (coordination, tracking). Time of blood sampling was predated to the third day of life. Screening was extended to biotinidase deficiency, congenital adrenal hyperplasia (CAH) and by introduction of tandem mass spectrometry for screening of many other disorders (besides PKU). Insurances now finance complete laboratory analysis which was transferred to the private sector. To enable all newborn to participate, the names of screened children are matched against birth lists by public health services on a regional basis. Recalls and conspicuous results are consistently followed up until disorders are either excluded or confirmed. Two clinical hotlines were established in the children's hospitals of the universities in Munich (Southern Bavaria) and in Erlangen (Northern Bavaria). Written consent is required for participation in the programme. Participation in the new programme could be continually increased; coverage is > 95% since April. In several cases screening was made up for not tested children by contacting their parents. Omitted screening was mostly due to misunderstandings regarding testing responsibility or lost samples. Altogether 52 cases of disorder were found in the 87,000 newborn screened until August 1999. Hence, the detection rate of children affected by inborn errors of metabolism was about twice as high than before changes. Among the newly screened diseases CAH was detected most often (11 cases). In 22 cases diagnosis was based on the use of tandem mass spectrometry. Among these (besides PKU, 9 cases) MCAD deficiency (6 cases) was detected most frequently. Whereas recall rates of most disorders were < 0.1%, screening for CAH still revealed a high recall rate, particularly in premature births. Second screening due to early discharge (< 48 h) was required in 1.3%. About 20% of pending recalls required contacting birth hospitals, doctors, midwives or parents. So far all affected children could be brought to treatment in time.

Milenkovic T, Vukovic R, Radojicic B, Mitrovic K, Todorovic S, Zatezalo L. Thirty years of the newborn screening program in Central Serbia: the missed cases of congenital hypothyroidism. Turk J Pediatr 2019; 61: 319- 324. Newborn Screening (NS) program for congenital hypothyroidism (CH) has completely changed the natural history of this devastating disorder for the vast majority of children with CH. However, cases of missed CH do happen, and it is important to keep this possibility in mind during every day clinical practice. The objective of this study was to analyze the recognized cases of undiagnosed CH by the NS program in Central Serbia in order to evaluate the reasons for such omissions. Data regarding the recognized missed cases of CH between the years of 1983 and 2013 were collected and analyzed. During 30 years of the NS program for CH on the territory of Central Serbia, 1,547,122 newborns were screened, and during this period, 14 children with CH were missed by the NS. Five missed cases were children with athyreosis (35.8%), 8 had ectopic thyroid gland (57.1%) and one child had dyshormonogenesis (7.1%). The median age at diagnosis of CH in these missed cases was 1.12 years (range 0.08-13.5 years). In the group of children with missed diagnosis of CH, 71.4% were missed due to errors during sample collection, and 28.6% of patients were missed due to false negative screening results. Continuous education of neonatologists as well as nurses in neonatal units of maternity hospital are necessary to avoid errors in sample collection. It is of high importance to notice in a discharge list if a child is referred to the hospital before the sample is taken in a maternity hospital. On the other hand, the maternity hospital has to inform the screening laboratory about any child who was referred to another hospital if the blood samples for screening are not taken. Parents should be better informed that each child has to be included in the NS which is obligatory in Serbia. In addition, awareness amongst pediatricians in primary care should be raised regarding the possibility of missed cases of CH.