Newborn Metabolic Screening Research Articles

The decision to discontinue screening for carnitine uptake disorder in New Zealand

When screening for carnitine uptake disorder (CUD), the New Zealand (NZ) newborn screening (NBS) service identified infants as screen-positive if they had initial and repeat free carnitine (C0) levels of less than 5.0 μmol/L. Since 2006, the NBS service has identified two infants with biochemical and genetic features consistent with neonatal CUD and nine mothers with features consistent with maternal CUD. A review of the literature suggests that these nine women reflect less than half the true prevalence and that CUD is relatively common. However, the NZ results (two infants) suggest a very low sensitivity and positive predictive value of NBS. While patients presenting with significant disease due to CUD are well described, the majority of adults with CUD are asymptomatic. Nonetheless, treatment with high-dose oral L-carnitine is recommended. Compliance with oral L-carnitine is likely to be poor long term. This may represent a specific risk as treatment could repress the usual compensatory mechanisms seen in CUD, such that a sudden discontinuation of treatment may be dangerous. L-carnitine is metabolized to trimethylamine-N-oxide (TMAO) and treated patients have extremely high plasma TMAO levels. TMAO is an independent risk factor for atherosclerosis and, thus, caution should be exercised regarding long-term treatment with high-dose carnitine of asymptomatic patients who may have a biochemical profile without disease. Due to these concerns, the NZ Newborn Metabolic Screening Programme (NMSP) initiated a review via a series of advisory and governance committees and decided to discontinue screening for CUD.

A retrospective biochemical, molecular, and neurocognitive review of Saudi patients with argininosuccinic aciduria

A retrospective review was compiled of 54 patients with argininosuccinic aciduria who were either identified through the Saudi National Newborn Screening Program or diagnosed clinically from January 2000 to December 2015. The duration of follow-up is from 2 to 19 years. The majority of patients (65%) originated from the central province of Saudi Arabia. The mean patient age at review was 10 years (2–19 years), 92% received an early diagnosis (<28 days of age) and most were symptomatic at the time of the diagnosis (n = 34). Normal ammonia at diagnosis was reported in 30% of patients, who were detected under the newborn metabolic screen (n = 5/16). A very high rate of consanguinity was observed in our cohort (98%). Developmental delay was the most detectable long term neurocognitive consequence followed by seizure disorder; 90.7% (n = 49) and 62.9% (n = 34) respectively. As expected, the severe neonatal form was the major presentation. The most common variant identified in this cohort was the previously reported founder c.1060C > T; p.(Gln354*) nonsense mutation in the ASL gene. In addition, the frequency of hyperammonemia was higher in patients homozygous for c.1060C > T; p.(Gln354*) compared to the other mutations. Interestingly, frequent thrombocytosis with the mean level of 717 × 109/L (range = 457–1169 × 109/L) was observed in 96% of the patients with no clear explanation.

Neonatal Cholestasis: A Pandora's Box.

Neonatal cholestasis (NC) is a diagnostic dilemma frequently countered in a neonatal care unit. Early diagnosis is vital for achieving an optimal patient outcome as many causes of cholestasis such as biliary atresia are time-sensitive and amenable to treatment if analyzed and treated early. Nonetheless, it is not generally simple to analyze these cases right on time as some of them are regularly missed due to the presence of pigmented stools, lack of newborn metabolic screening, and named as instances of prolonged jaundice. In this manner, we prescribe to explore all reasons for prolonged jaundice stretching out past 14 days in neonates. Besides, we suggest that stool card ought to be a piece of release rundown for all newborn children being released from the nursery. This is of most extreme significance in the nation like India where guaranteeing customary follow-up is as yet a tough assignment. These stool cards will help in the early determination of patients with NC particularly biliary atresia and guarantee their auspicious cure. Another reason which needs exceptional say is parenteral nutrition–associated liver illness, as the proportion of preterm babies is getting greater and greater with better neonatal care. These extreme preterm infants are in the requirement for prolonged (>14 days) total parenteral nourishment because of which they are at high hazard for NC contrasted with their more developed peers. In this survey, we will give an understanding of clinical approach, differential diagnosis, and clinical review of NC.

Effectiveness of The Alberta Newborn Metabolic Screening Program for Congenital Adrenal Hyperplasia

Effectiveness of The Alberta Newborn Metabolic Screening Program for Congenital Adrenal Hyperplasia

Presymptomatic Diagnosis of Spinal Muscular Atrophy Through Newborn Screening

To demonstrate the feasibility of presymptomatic diagnosis of spinal muscular atrophy (SMA) through newborn screening (NBS). We performed a screening trial to assess all newborns who underwent routine newborn metabolic screening at the National Taiwan University Hospital newborn screening center between November 2014 and September 2016. A real-time polymerase chain reaction (RT-PCR) genotyping assay for the SMN1/SMN2 intron 7 c.888+100A/G polymorphism was performed to detect homozygous SMN1 deletion using dried blood spot (DBS) samples. Then the exon 7 c.840C>T mutation and SMN2 copy number were determined by both droplet digital PCR (ddPCR) using the original screening DBS and multiplex ligation-dependent probe amplification (MLPA) using a whole blood sample. Of the 120 267 newborns, 15 tested positive according to the RT-PCR assay. The DBS ddPCR assay excluded 8 false-positives, and the other 7 patients were confirmed by the MLPA assay. Inclusion of the second-tier DBS ddPCR screening assay resulted in a positive prediction value of 100%. The incidence of SMA was 1 in 17 181 (95% CI, 1 in 8323 to 1 in 35 468). Two of the 3 patients with 2 copies of SMN2 and all 4 patients with 3 or 4 copies of SMN2 were asymptomatic at the time of diagnosis. Five of the 8 false-positives were caused by intragenic recombination between SMN1 and SMN2. Newborn screening can detect patients affected by SMA before symptom onset and enable early therapeutic intervention. A combination of a RT-PCR and a second-tier ddPCR can accurately diagnose SMA from DBS samples with no false-positives. ClinicalTrials.gov NCT02123186.

Reference values of amino acids, acylcarnitines and succinylacetone by tandem mass spectrometry for use in newborn screening in southwest Colombia.

Introduction: Inborn errors of metabolism (IEM) represent an important public health problem due to current diagnosis and treatment limitations, poor life quality of affected patients, and consequent untimely child death. In contrast to classical methods, tandem mass spectrometry (MS/MS) has allowed simultaneous evaluation of multiple metabolites associated with IEM offering higher sensitivity, low false positive rates and high throughput.Aims: Determine concentration levels for amino acids and acylcarnitines in blood of newborns from Colombia, to establish reference values for further use in diagnosis of IEM.Methods: Implementation of a method to determine amino acids, acylcarnitines and succinylacetone in newborn dried blood spots using MS/MS, and its application in a cross-sectional study conducted in 891 healthy neonates from Cali and Quibdo cities is described. Results: fifty-seven analytes that allow the diagnosis of more than 40 different pathologies were tested. The method showed to be linear, precise and accurate. Healthy neonates 1-18 days of age were included, 523 from Cali and 368 from Quibdo; 52% male and 48% female. Age-related differences on the concentration levels of amino acids and acylcarnitines were observed whereas no significant differences by gender were found. Conclusion: The study has contributed to reveal the usual concentration levels of amino acids, acylcarnitines and succinylacetone that could be used as reference for the establishment of a newborn metabolic screening program in Colombia.

The Risk of Fatty Acid Oxidation Disorders and Organic Acidemias in Children with Normal Newborn Screening.

New Zealand has undertaken expanded newborn screening since 2006. During that period there have been no reported cases of fatty acid oxidation disorders or organic acidemias that have been diagnosed clinically that the screening programme missed. However there may have been patients that presented clinically that were not diagnosed correctly or notified.In order to investigate the false-negative screening rate a case-control study was undertaken whereby the clinical coding data and relevant medical records were reviewed for 150 controls and 525 cases. The cases had normal newborn screening but with key analytes and/or ratios just below the notification level for individual disorders and thus in theory were most at risk of having metabolic disease.Two cases had medical histories suggestive of metabolic disease and thus could represent a false-negative screen. One of these had marginally elevated octanoyl carnitine levels and thus possible medium-chain acyl Co-A dehydrogenase deficiency (MCADD) while the other had elevated isovaleryl carnitine and thus may have been a case of isovaleric acidemia (IVA). However, subsequent molecular analysis revealed that the diagnosis of MCADD and IVA was unlikely.Despite relatively high cut-offs the New Zealand Newborn Metabolic Screening Programme does not appear to have missed any confirmed cases of fatty acid oxidation disorders and organic acidemias in its first 8 years of expanded newborn screening. This would suggest a similar low false-negative screening rate in centres with comparable screening protocols and would indicate that the risk of fatty acid oxidation disorders and classical organic acidemias in children who had normal newborn screening is low.

Screening for medium-chain acyl CoA dehydrogenase deficiency: current perspectives

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common disorder associated with fatty acid oxidation. The disorder is characterized by inability to generate sufficient energy from fatty acid metabolism during periods of catabolic stress caused by intercurrent illness or prolonged fasting. The metabolic consequences are severe and include hypoketotic hypoglycemia leading to a Reye-like hepatic encephalopathy syndrome and sudden death. If individuals are detected before a life-threatening episode, the complications of MCAD deficiency are preven table. Newborn metabolic screening enables the early detection of MCAD deficiency in many countries worldwide. The metabolic marker for MCAD deficiency (C8) can be detected with a high degree of sensitivity in the newborns by tandem mass spectrometry. The 985A.G (K329E) mutation accounts for the majority of disease alleles, and approximately 47%-80% of MCAD patients are homozygotes for this mutation. Newborns homozygous for the 985A.G mutation have higher octanoylcarnitine levels than those who are heterozygous for 985A.G mutation or possess other genotypes. Time of sampling after birth and prematurity may affect the octanoylcarnitine levels in MCAD-deficient newborns.

Gestational dating by metabolic profile at birth: a California cohort study

BackgroundAccurate gestational dating is a critical component of obstetric and newborn care. In the absence of early ultrasound, many clinicians rely on less accurate measures, such as last menstrual period or symphysis-fundal height during pregnancy, or Dubowitz scoring or the Ballard (or New Ballard) method at birth. These measures often underestimate or overestimate gestational age and can lead to misclassification of babies as born preterm, which has both short- and long-term clinical care and public health implications.ObjectiveWe sought to evaluate whether metabolic markers in newborns measured as part of routine screening for treatable inborn errors of metabolism can be used to develop a population-level metabolic gestational dating algorithm that is robust despite intrauterine growth restriction and can be used when fetal ultrasound dating is not available. We focused specifically on the ability of these markers to differentiate preterm births (PTBs) (<37 weeks) from term births and to assign a specific gestational age in the PTB group.Study DesignWe evaluated a cohort of 729,503 singleton newborns with a California birth in 2005 through 2011 who had routine newborn metabolic screening and fetal ultrasound dating at 11–20 weeks’ gestation. Using training and testing subsets (divided in a ratio of 3:1) we evaluated the association among PTB, target newborn characteristics, acylcarnitines, amino acids, thyroid-stimulating hormone, 17-hydroxyprogesterone, and galactose-1-phosphate-uridyl-transferase. We used multivariate backward stepwise regression to test for associations and linear discriminate analyses to create a linear function for PTB and to assign a specific week of gestation. We used sensitivity, specificity, and positive predictive value to evaluate the performance of linear functions.ResultsAlong with birthweight and infant age at test, we included 35 of the 51 metabolic markers measured in the final multivariate model comparing PTBs and term births. Using a linear discriminate analyses-derived linear function, we were able to sort PTBs and term births accurately with sensitivities and specificities of ≥95% in both the training and testing subsets. Assignment of a specific week of gestation in those identified as PTBs resulted in the correct assignment of week ±2 weeks in 89.8% of all newborns in the training and 91.7% of those in the testing subset. When PTB rates were modeled using the metabolic dating algorithm compared to fetal ultrasound, PTB rates were 7.15% vs 6.11% in the training subset and 7.31% vs 6.25% in the testing subset.ConclusionWhen considered in combination with birthweight and hours of age at test, metabolic profile evaluated within 8 days of birth appears to be a useful measure of PTB and, among those born preterm, of specific week of gestation ±2 weeks. Dating by metabolic profile may be useful in instances where there is no fetal ultrasound due to lack of availability or late entry into care.

Predicting gestational age using neonatal metabolic markers

BackgroundAccurate gestational age estimation is extremely important for clinical care decisions of the newborn as well as for perinatal health research. Although prenatal ultrasound dating is one of the most accurate methods for estimating gestational age, it is not feasible in all settings. Identifying novel and accurate methods for gestational age estimation at birth is important, particularly for surveillance of preterm birth rates in areas without routine ultrasound dating.ObjectiveWe hypothesized that metabolic and endocrine markers captured by routine newborn screening could improve gestational age estimation in the absence of prenatal ultrasound technology.Study DesignThis is a retrospective analysis of 230,013 newborn metabolic screening records collected by the Iowa Newborn Screening Program between 2004 and 2009. The data were randomly split into a model-building dataset (n = 153,342) and a model-testing dataset (n = 76,671). We performed multiple linear regression modeling with gestational age, in weeks, as the outcome measure. We examined 44 metabolites, including biomarkers of amino acid and fatty acid metabolism, thyroid-stimulating hormone, and 17-hydroxyprogesterone. The coefficient of determination (R2) and the root-mean-square error were used to evaluate models in the model-building dataset that were then tested in the model-testing dataset.ResultsThe newborn metabolic regression model consisted of 88 parameters, including the intercept, 37 metabolite measures, 29 squared metabolite measures, and 21 cubed metabolite measures. This model explained 52.8% of the variation in gestational age in the model-testing dataset. Gestational age was predicted within 1 week for 78% of the individuals and within 2 weeks of gestation for 95% of the individuals. This model yielded an area under the curve of 0.899 (95% confidence interval 0.895−0.903) in differentiating those born preterm (<37 weeks) from those born term (≥37 weeks). In the subset of infants born small-for-gestational age, the average difference between gestational ages predicted by the newborn metabolic model and the recorded gestational age was 1.5 weeks. In contrast, the average difference between gestational ages predicted by the model including only newborn weight and the recorded gestational age was 1.9 weeks. The estimated prevalence of preterm birth <37 weeks’ gestation in the subset of infants that were small for gestational age was 18.79% when the model including only newborn weight was used, over twice that of the actual prevalence of 9.20%. The newborn metabolic model underestimated the preterm birth prevalence at 6.94% but was closer to the prevalence based on the recorded gestational age than the model including only newborn weight.ConclusionsThe newborn metabolic profile, as derived from routine newborn screening markers, is an accurate method for estimating gestational age. In small-for-gestational age neonates, the newborn metabolic model predicts gestational age to a better degree than newborn weight alone. Newborn metabolic screening is a potentially effective method for population surveillance of preterm birth in the absence of prenatal ultrasound measurements or newborn weight.

Selective Metabolic Screening from a Neonatology Perspective

Metabolic diseases are quite rare diseases when considered alone, but they are affecting approximately 1:3.000–4.000 of live births when considering the cumulative meaning. Particularly considering that diseases are inherited genetically, “screening programs for metabolic disease” is very important for those aiming people not only live but also quality to live. Screening feasible in neonates can be analyzed in two groups such as general screening and selective screening tests. The general screening tests are further divided into Newborn Metabolic Screening Program and Expanded Newborn Screening. As a large part of metabolic diseases do not affect the baby at birth, all live-born neonates without any clinical findings are implemented in the process of screening programs at a proper time. This application is called as “Newborn Metabolic Screening Program”, and it is made considering the reality of each country with different diseases and limit values. Tandem mass spectrometry (Tandem MS/MS) can not take place in a national screening programme; although a very expensive analytical instrument, the testing is cost-effective because screening of more than 30 diseases is possible with one drop of blood. This practice has been widespread since the last 15 years defined as “Expanded Newborn Screening”. Newborns with a positive family history for metabolic disease (defined as metabolic disease or death from a metabolic disease in the family) and/ or neonates with clinical symptoms suggestive of metabolic diseases; implementation of selected tests for targeted metabolic disease or metabolic disease group considered as “Selective Metabolic Screening Tests”. This is, usually, a strategy carried out in developing countries. The aim is to get a clue to define the maximum number of possible metabolic diseases in the shortest period that can lead to serious problems. On the other hand, it should be known that if the “selective screening test is negative”, it does not mean “there is no disease’’. Newborn metabolic screening tests performed for the early recognition of inherited metabolic diseases is basically a public health service. Considering this aspect, it is not only a laboratory service but also an integration of systems including education, data assessment, diagnosis, treatment, and long-term management approach. (JAREM 2015; 5: 39-46)

Deconstructing Black Swans: An Introductory Approach to Inherited Metabolic Disorders in the Neonate.

Inherited metabolic disorders (IMDs) are individually rare but collectively common disorders that frequently require rapid or urgent therapy. This article provides a generalized approach to IMDs, as well as some investigations and safe therapies that may be initiated pending the metabolic consult. An overview of the research supporting management strategies is provided. In addition, the newborn metabolic screen is reviewed. Caring for infants with IMDs can seem difficult because each of the types is rarely seen; however, collectively the management can be seen as similar. When an IMD is suspected, a metabolic specialist should be consulted for expert advice regarding appropriate laboratory investigations and management. Because rapid intervention of IMDs before the onset of symptoms may prevent future irreversible sequelae, each abnormal newborn screen must be addressed promptly. Management can be difficult. Research in this area is limited and can be difficult without multisite coordination since sample sizes of any significance are difficult to achieve.

Research in brief

Research in brief

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

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. 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. 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. 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.

The Big Screen Difference

The Big Screen Difference

Actionable recommendations in the Bright Futures child health supervision guidelines.

With the growing use of electronic health record systems, there is a demand for an electronic version of the leading American pediatric preventive care guideline, Bright Futures. As computer implementation requires actionable recommendations, it is important to assess to what degree Bright Futures meets criteria for actionability. We aimed to 1) determine the number of actionable recommendations in the current edition of Bright Futures and 2) to recommend a specific format for representing an important class of guidelines in a way that better facilitates computer implementation. We consolidated all action statements in Bright Futures into recommendations. We then used two dimensions (decidability and executability) in the Guideline Implementability Appraisal v 2.0 (GLIA) to determine the actionability of the recommendations. Decidability means the recommendation states precisely under what conditions to perform those actions. Executability means actions are stated specifically, unambiguously and in sufficient detail. The results were presented in a figure titled Service Interval Diagram (SID), describing actionable recommendations, age intervals during which they are applicable, and how frequently they should occur in that interval. We consolidated 2161 action items into 245 recommendations and identified 52 that were actionable (21%). Almost exclusively, these recommendations addressed screening, such as newborn metabolic screening, or child safety, such as car seat use. A limited number (n=13) of recommendations for other areas of anticipatory guidance were also actionable. No recommendations on child discipline, family function or mental health met our criteria for actionability. The SID representing these recommendations is presented in a figure. Only a portion of the Bright Futures Guidelines meets criteria for actionability. Substantial work lies ahead to develop most recommendations for anticipatory guidance into a computer implementable format.

Screening criteria: the need to deal with new developments and ethical issues in newborn metabolic screening

Newborn metabolic screening is the most widespread application of screening technology and provides the most comprehensive application of genetics in health services, where the Guthrie blood spot cards allow screening for metabolic diseases in close to 100 % of all newborn babies. Despite over 40 years of use and significant benefits to well in excess of 100,000 children worldwide, there is remarkably little consensus in what conditions should be screened for and response to new advances in medicine relating to programme expansion. In this article, the international criteria for newborn metabolic screening are considered, and we propose that these criteria are poorly developed in relation to the baby, its family and society as a whole. Additionally, the ethical issues that should inform the application of screening criteria are often not developed to a level where a consensus might easily be achieved. We also consider that when family interests are factored in to the decision-making process, they have a significant influence in determining the list of diseases in the panel, with countries or states incorporating family and societal values being the most responsive. Based on our analysis, we propose that decision criteria for metabolic screening in the newborn period should be adapted to specifically include parent and family interests, community values, patients’ rights, duties of government and healthcare providers, and ethical arguments for action in the face of uncertainty.

A further patient with van Maldergem syndrome

We report on a male patient with the proposed diagnosis of the rare but very distinct entity of van Maldergem syndrome.His parents are first cousins. At the age of 4 years the boy presented with severe developmental delay, talipes equinovarus, finger camptodactyly with interphalangeal pterygium, joint laxity, bilateral microtia, and a dysmorphic facies. He showed bilateral epicanthus, telecanthus, short palpebral fissures, broad flat nasal bridge, and dental malocclusion. The combination of the specific facial features with camptodactyly, interphalangeal pterygium, joint laxity and developmental delay led to the diagnosis of van Maldergem syndrome. The medical history was further on significant for pharyngeal instability requiring the placement of a tracheostomy tube, an inguinal hernia, hip subluxation, small kidneys and genital abnormalities (micropenis, bifid scrotum, cryptorchidism). Due to severe feeding difficulties permanent tube feeding was required. Metabolic tests (newborn metabolic screening, 7-dehydrocholesterol, amino acids, organic acids in urine) and chromosomal analysis (450–500 bands; 46,XY) were normal. Molecular karyotyping revealed two parental CNVs (paternal deletion of 9q33.1; maternal duplication of 11p15.1), which are unlikely to contribute to the patient's phenotype.Taken together, the report on a further patient with van Maldergem syndrome expands the clinical spectrum of the condition by adding genital malformations, hernia, pharyngeal instability, and subluxation of the hip.

Carnitine Palmitoyltransferase-1A Deficiency

Carnitine palmitoyltransferase-1A (CPT-1A) deficiency is a defect of fatty acid metabolism that presents as an autosomal recessive inheritance. Carnitine palmitoyltransferase-1A is the rate-limiting enzyme that allows the body to process fats to provide energy during times of fasting and illness. Patients usually present between birth and 18 months of age following an illness with various symptoms including hypoketotic hypoglycemia, lethargy, and seizures. Diagnosis can be achieved through newborn metabolic screening. Long-term treatment is managed through dietary management. A milder form has been found to occur at a much higher incidence in the Inuit population. Since the recent discovery of CPT-1A deficiency, much is yet to be learned. Researchers are busy identifying and studying groups of people who are presenting with CPT-1A deficiency at significantly higher rates than the general population. This research will lead to a better understanding and future care of individuals diagnosed with CPT-1A deficiency.

Prevalence of congenital cytomegalovirus infection in Slovenia: A study on 2,841 newborns

Human cytomegalovirus (CMV) is the most frequent cause of congenital infection in humans. In the first prevalence study of congenital CMV infection in Eastern and Central Europe, all neonates born in a 22-month period in two Slovenian maternity units (total of 2,841 newborns) were screened prospectively for congenital CMV infection by a real-time polymerase chain reaction (PCR) in urine. In all newborns with positive screening results, plasma and dried blood spots (DBS) collected at birth were tested additionally for CMV DNA. Congenital CMV infection was confirmed by virus isolation from a urine sample collected within the first 2 weeks of life. Congenital CMV infection was identified in four out of 2,841 newborns tested (incidence 0.14%; 95% CI, 0.05-0.39%). In four newborns with confirmed congenital infection, the concentration of CMV DNA in urine ranged from 4.68 to 8.18 log(10) copies/ml, all four newborns had detectable CMV DNA in plasma taken at birth (1.26-3.34 log(10) copies/ml) and two out of four had detectable CMV DNA in DBS collected during newborn metabolic screening. None of the four newborns with confirmed congenital CMV infection was symptomatic. The study showed that the prevalence of congenital CMV infection at birth in Slovenia is among the lowest in the world and that CMV DNA PCR testing of urine is a suitable and affordable real-time screening strategy for congenital CMV infection. If it is performed in 24 mini-pools, the cost of screening is 1.4 €/newborn and the cost of detecting a single newborn with congenital CMV infection 1,000 €.