scholarly journals Diagnosis of Classic Homocystinuria in Two Boys Presenting with Acute Cerebral Venous Thrombosis and Neurologic Dysfunction after Normal Newborn Screening

2021 ◽  
Vol 7 (3) ◽  
pp. 48
Author(s):  
Alexander Asamoah ◽  
Sainan Wei ◽  
Kelly E. Jackson ◽  
Joseph H. Hersh ◽  
Harvey Levy

Homocystinuria, caused by cystathionine β-synthase deficiency, is a rare inherited disorder involving metabolism of methionine. Impaired synthesis of cystathionine leads to accumulation of homocysteine that affects several organ systems leading to abnormalities in the skeletal, cardiovascular, ophthalmic and central nervous systems. We report a 14-month-old and a 7-year-old boy who presented with neurologic dysfunction and were found to have cerebral venous sinus thromboses on brain magnetic resonance imaging (MRI)/magnetic resonance venogram (MRV) and metabolic and hypercoagulable work-up were consistent with classic homocystinuria. The 14-month-old boy had normal newborn screening. The 7-year-old boy initially had an abnormal newborn screen for homocystinuria but second tier test that consisted of total homocysteine was normal, so his newborn screen was reported as normal. With the advent of expanded newborn screening many treatable metabolic disorders are detected before affected infants and children become symptomatic. Methionine is the primary target in newborn screening for homocystinuria and total homocysteine is a secondary target. Screening is usually performed after 24–48 h of life in most states in the US and some states perform a second screen as a policy on all tested newborns or based on when the initial newborn screen was performed. This is done in hopes of detecting infants who may have been missed on their first screen. In the United Kingdom, NBS using dried blood spot is performed at 5 to 8 days after birth. It is universally known that methionine is a poor target and newborn screening laboratories have used different cutoffs for a positive screen. Reducing the methionine cutoff increases the sensitivity but not necessarily the specificity of the test and increasing the cutoff will miss babies who may have HCU whose levels may not be high enough to be detected at their age of ascertainment. It is not clear whether adjusting methionine level to decrease the false negative rates combined with total homocysteine as a second-tier test can be used effectively and feasibly to detect newborns with HCU. Between December 2005 and December 2020, 827,083 newborns were screened in Kentucky by MS/MS. Kentucky NBS program uses the postanalytical tools offered by the Collaborative Laboratory Integrated Reports (CLIR) project which considers gestational age and birthweight. One case of classical homocystinuria was detected and two were missed on first and second tier tests respectively. The newborn that had confirmed classical homocystinuria was one of twenty-three newborns that were referred for second tier test because of elevated methionine (cutoff is >60 µmol/L) and/or Met/Phe ratio (cutoff is >1.0); all 23 dried blood spots had elevated total homocysteine. One of the subjects of this case report had a normal methionine on initial screen and the other had a normal second-tier total homocysteine level. The performance of methionine and total homocysteine as screening analytes for homocystinuria suggest that it may be time for newborn screening programs to consider adopting next generation sequencing (NGS) platforms as alternate modality of metabolic newborn screening. Because of cost considerations, newborn screening programs may not want to adopt NGS, but the downstream healthcare cost incurred due to missed cases and the associated morbidity of affected persons far exceed costs to newborn screen programs. Since NGS is becoming more widely available and inexpensive, it may be feasible to change testing algorithms to use Newborn Metabolic NGS as the primary mode of testing on dry blood specimens with confirmation with biochemical testing. Some commercial laboratories have Newborn Screening Metabolic gene panel that includes all metabolic disorders on the most comprehensive newborn screening panel in addition to many other conditions that are not on the panel. A more targeted NGS panel can be designed that may not cost much and eventually help avoid the pitfalls associated with delayed diagnosis and cost of screening.

Author(s):  
Gurjit Kaur ◽  
Kiran Thakur ◽  
Sandeep Kataria ◽  
Teg Rabab Singh ◽  
Bir Singh Chavan ◽  
...  

AbstractNewborn 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.


PEDIATRICS ◽  
1993 ◽  
Vol 91 (6) ◽  
pp. 1203-1209
Author(s):  

Congenital hypothyroidism (CH) represents one of the most common preventable causes of mental retardation. The fetal hypothalamic-pituitary-thyroid axis begins to function by midgestation and is mature in the term infant at delivery. If fetal hypothyroidism develops, untoward effects may be demonstrated in certain organ systems, including the central nervous system and skeleton. However, most infants with CH appear normal at birth. Recent data suggest that the hypothyroid fetus is protected to a certain extent by placental transfer of maternal thyroid hormone; serum thyroxine (T4) levels in the cord blood of athyroid fetuses approximate one third of maternal levels.1 In addition, studies in animal models of hypothyroidism demonstrate increased levels of brain iodothyronine deiodinase, the enzyme which converts T4 to triiodothyronine (T3). In the hypothyroid fetus, this increased enzyme acting on T4 of maternal origin is sufficient to produce near normal fetal brain T3 concentrations.2 Thus, it appears that early detection and treatment of congenital hypothyroidism should have the potential to completely reverse the effects of fetal hypothyroidism in all but the most severe cases, for example, athyreotic infants born to mothers with thyroid problems resulting in inadequate placental transfer of maternal thyroid hormone. Since the development of pilot screening programs for CH in Quebec and Pittsburgh in 1974,3 newborn screening for CH has become routine in essentially all developed countries of the world and is under development in Eastern Europe, South America, Asia, and Africa. In North America it is estimated that more than 5 million newborns are screened, with approximately 1400 infants with congenital hypothyroidism detected annually.


2020 ◽  
Vol 6 (1) ◽  
pp. 10 ◽  
Author(s):  
Dawn S. Peck ◽  
Jean M. Lacey ◽  
Amy L. White ◽  
Gisele Pino ◽  
April L. Studinski ◽  
...  

Enzyme-based newborn screening for Mucopolysaccharidosis type I (MPS I) has a high false-positive rate due to the prevalence of pseudodeficiency alleles, often resulting in unnecessary and costly follow up. The glycosaminoglycans (GAGs), dermatan sulfate (DS) and heparan sulfate (HS) are both substrates for α-l-iduronidase (IDUA). These GAGs are elevated in patients with MPS I and have been shown to be promising biomarkers for both primary and second-tier testing. Since February 2016, we have measured DS and HS in 1213 specimens submitted on infants at risk for MPS I based on newborn screening. Molecular correlation was available for 157 of the tested cases. Samples from infants with MPS I confirmed by IDUA molecular analysis all had significantly elevated levels of DS and HS compared to those with confirmed pseudodeficiency and/or heterozygosity. Analysis of our testing population and correlation with molecular results identified few discrepant outcomes and uncovered no evidence of false-negative cases. We have demonstrated that blood spot GAGs analysis accurately discriminates between patients with confirmed MPS I and false-positive cases due to pseudodeficiency or heterozygosity and increases the specificity of newborn screening for MPS I.


2020 ◽  
Vol 6 (4) ◽  
pp. 91
Author(s):  
Lorne A. Clarke ◽  
Patricia Dickson ◽  
N. Matthew Ellinwood ◽  
Terri L. Klein

There have been significant advances allowing for the integration of mucopolysaccharidosis I into newborn screening programs. Initial experiences using a single-tier approach for this disorder have highlighted shortcomings that require immediate remediation. The recent evaluation of a second-tier biomarker integrated into the MPS I newborn screening protocol has been demonstrated to greatly improve the precision and predictive value of newborn screening for this disorder. This commentary urges newborn screening programs to learn from these experiences and improve newborn screening for mucopolysaccharidosis I and future mucopolysaccharidoses newborn screening programs by implementation of a second-tier biomarker analyte.


2019 ◽  
Vol 5 (2) ◽  
pp. 19 ◽  
Author(s):  
Arieh Cohen ◽  
Marta Baurek ◽  
Allan Lund ◽  
Morten Dunø ◽  
David Hougaard

Galactosaemia has been included in various newborn screening programs since 1963. Several methods are used for screening; however, the predominant methods used today are based on the determination of either galactose-1-phosphate uridyltransferase (GALT) activity or the concentration of total galactose. These methods cannot be multiplexed and therefore require one full punch per sample. Since the introduction of mass spectrometry in newborn screening, many diseases have been included in newborn screening programs. Here, we present a method for including classical galactosaemia in an expanded newborn screening panel based on the specific determination of galactose-1-phosphate by tandem mass spectrometry. The existing workflow only needs minor adjustments, and it can be run on the tandem mass spectrometers in routine use. Furthermore, compared to the currently used methods, this novel method has a superior screening performance, producing significantly fewer false positive results. We present data from 5500 routine newborn screening samples from the Danish Neonatal Screening Biobank. The cohort was enriched by including 14 confirmed galactosaemia positive samples and 10 samples positive for other metabolic disorders diagnosed through the Danish newborn screening program. All galactosaemia positive samples were identified by the method with no false positives. Furthermore, the screening performance for other metabolic disorders was unaffected.


2006 ◽  
Vol 52 (3) ◽  
pp. 482-487 ◽  
Author(s):  
Johannes Sander ◽  
Nils Janzen ◽  
Michael Peter ◽  
Stefanie Sander ◽  
Ulrike Steuerwald ◽  
...  

Abstract Background: False-positive and false-negative results occur in current newborn-screening programs for hepatorenal tyrosinemia, which measure tyrosine concentrations in blood spots, sometimes in combination with other metabolites, including succinylacetone. We present our experience with a newly described method for succinylacetone quantification in routine newborn screening. Methods: Succinylacetone was extracted from blood spots that had already been extracted with absolute methanol for acylcarnitine and amino acid analysis. The solvent was acetonitrile–water (80:20 by volume) containing formic acid, hydrazine hydrate, and 100 nmol/L 5,7-dioxooctanoic acid as internal standard. Analysis was performed by tandem mass spectrometry in a separate run. Results: Of 61 344 samples, 99.6% had succinylacetone concentrations ≤5 μmol/L. With a cutoff of 10 μmol/L, no false-positive results were obtained. In 2 patients, the succinylacetone concentrations in the dried blood spots from the 36th and 56th hours of life were 152 and 271 μmol/L, respectively, and the tyrosine concentrations were 54 and 129 μmol/L. Hepatorenal tyrosinemia was subsequently confirmed in both patients. Retrospective analysis of the neonatal screening samples of 2 additional known patients revealed increased succinylacetone concentrations of 46 and 169 μmol/L, respectively. Conclusions: Tandem mass spectrometric quantification directly from residual blood spots is a useful method for the early detection of hepatorenal tyrosinemia in newborn-screening programs.


2003 ◽  
Vol 49 (11) ◽  
pp. 1797-1817 ◽  
Author(s):  
Donald H Chace ◽  
Theodore A Kalas ◽  
Edwin W Naylor

Abstract Background: Over the past decade laboratories that test for metabolic disorders have introduced tandem mass spectrometry (MS/MS), which is more sensitive, specific, reliable, and comprehensive than traditional assays, into their newborn-screening programs. MS/MS is rapidly replacing these one-analysis, one-metabolite, one-disease classic screening techniques with a one-analysis, many-metabolites, many-diseases approach that also facilitates the ability to add new disorders to existing newborn-screening panels. Methods: During the past few years experts have authored many valuable articles describing various approaches to newborn metabolic screening by MS/MS. We attempted to document key developments in the introduction and validation of MS/MS screening for metabolic disorders. Our approach used the perspective of the metabolite and which diseases may be present from its detection rather than a more traditional approach of describing a disease and noting which metabolites are increased when it is present. Content: This review cites important historical developments in the introduction and validation of MS/MS screening for metabolic disorders. It also offers a basic technical understanding of MS/MS as it is applied to multianalyte metabolic screening and explains why MS/MS is well suited for analysis of amino acids and acylcarnitines in dried filter-paper blood specimens. It also describes amino acids and acylcarnitines as they are detected and measured by MS/MS and their significance to the identification of specific amino acid, fatty acid, and organic acid disorders. Conclusions: Multianalyte technologies such as MS/MS are suitable for newborn screening and other mass screening programs because they improve the detection of many diseases in the current screening panel while enabling expansion to disorders that are now recognized as important and need to be identified in pediatric medicine.


2020 ◽  
Vol 6 (1) ◽  
pp. 22
Author(s):  
Raymond Y. Wang

Pompe disease is an inherited lysosomal storage disorder caused by acid alpha-glucosidase (GAA) enzyme deficiency, resulting in muscle and neuron intralysosomal glycogen storage. Clinical symptoms vary from the severe, infantile-onset form with hypertrophic cardiomyopathy, gross motor delay, and early death from respiratory insufficiency; to a late-onset form with variable onset of proximal muscle weakness and progressive respiratory insufficiency. Newborn screening programs have been instituted to presymptomatically identify neonates with infantile-onset Pompe disease for early initiation of treatment. However, infants with late-onset Pompe disease are also identified, leaving families and physicians in a state of uncertainty regarding prognosis, necessity, and timing of treatment initiation. This report presents a 31 5/7 weeks’ gestational age premature infant flagged positive for Pompe disease with low dried blood spot GAA activity; sequencing identified biparental c.-32-13T>G/c.29delA GAA variants predicting late-onset Pompe disease. The infant’s parents’ initial reactions to the positive newborn screen, subsequent experience during confirmatory testing, and post-confirmation reflections are also reported. While uncertainties regarding natural history and prognosis of presymptomatically-identified late-onset Pompe disease infants will be elucidated with additional experience, suggestions for education of first-line providers are provided to accurately communicate results and compassionately counsel families regarding anxiety-provoking positive newborn screen results.


2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
F. Neemuchwala ◽  
M. Taki ◽  
E. Secord ◽  
S. Z. Nasr

Newborn screening for cystic fibrosis (CF) enables early diagnosis and treatment leading to improved health outcomes for patients with CF. Although the sensitivity of newborn screening is high, false-negative results can still occur which can be misleading if clinicians are not aware of the clinical presentation of CF. We present a case of a young male with negative newborn screen diagnosed for CF. He was diagnosed at 3 years of age despite having symptoms indicative of CF since infancy. The delayed diagnosis resulted in diffuse lung damage and poor growth.


2012 ◽  
Vol 97 (12) ◽  
pp. 1043-1047 ◽  
Author(s):  
Jacqui Calvin ◽  
Sarah L Hogg ◽  
Donna McShane ◽  
Sharon Anne McAuley ◽  
Richard Iles ◽  
...  

BackgroundNewborn screening for cystic fibrosis (CF) relies on the measurement of immunoreactive trypsinogen (IRT) originating from the pancreas. The Norfolk, Suffolk and Cambridgeshire screening programme initially exploited the persistent increase in IRT seen in CF (IRT-IRT protocol) and later changed to include mutation analysis as a second tier test (IRT-DNA-IRT protocol).ResultsDuring a 30 year period 582 966 babies have been screened by IRT-IRT and 147 764 by IRT-DNA-IRT (total 730730), resulting in 296 screen positive cases of CF and 29 false negatives (including 10 false negatives with meconium ileus). Ten missed CF cases were pancreatic insufficient, however all were diagnosed before their first birthday, suggesting that a false negative result did not forestall appropriate clinical investigation. The IRT-DNA-IRT protocol had a much improved positive predictive value (PPV) of 85.9% compared to 67.3% for IRT-IRT, excluding CF babies with meconium ileus. The PPVs increased to 82.2% and 98.2% respectively if only well, term babies were considered. The main factor to account for this improvement in PPV has probably been the incorporation of DNA analysis in the second tier testing.ConclusionsThe diagnosis of screen-positive babies proved difficult in a minority of cases with the classification of some patients changing with evolving phenotype. Our results illustrate the importance of collecting outcome data over a long time period for accurate assessment of the screening programme. This study provides evidence that newborn screening for CF is a valid undertaking that detects 95% of unsuspected CF cases presenting before 3 years of age.


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