Table of Contents

Early diagnosis of males with X-linked adrenoleukodystrophy (X-ALD) is essential for preventing loss of life due to adrenal insufficiency and for timely therapy of the childhood cerebral form of X-ALD with hematopoietic cell transplantation. This article describes X-ALD, the current therapies, the history of the development of the newborn screening test, the approval by the Secretary of Health and Human Services for the addition of X-ALD newborn screening to the recommended uniform panel of disorders screened as newborns (RUSP) and the successful implementation of X-ALD newborn screening in the state of New York beginning on 30 December 2013. Follow-up guidelines that have been established in New York are outlined. Based on the success of newborn screening in New York, and early results in Connecticut, where X-ALD newborn screening started in December 2015, and in California, where X-ALD newborn screening began in September 2016, we are confident and hopeful that X-ALD newborn screening will expand to include all US states and to countries that have established neonatal screening programs. The Minster of Health in the Netherlands has approved the addition of X-ALD to the newborn screening program with a start date expected in 2017. The states, such as Massachusetts, Illinois, Minnesota, New Jersey, Florida and Washington, that have legislative approval will commence screening as soon as budgetary resources, testing and follow-up procedures are in place. Full article

Newborn screening has revolutionized the diagnosis of many disorders, notably metabolic disorders. Whereas, formerly, a clinical presentation of developmental delay or other features led to the diagnosis, usually too late for optimal treatment, today it is an abnormal finding in newborn screening which leads to the diagnosis and presymptomatic preventative therapy. It is my good fortune to have been involved in newborn screening for virtually all of my 50 years in metabolic disorders—the first 31 years with direct involvement. I have been part of the expansion of newborn screening from the time of the original Guthrie bacterial assays to the addition of tandem mass spectrometry. Newborn screening continues to be a central part of my professional life. This article describes my journey in newborn screening as a metabolic physician and the hallmarks of this journey within the rich history of newborn screening. Full article

Guanidinoacetate methyltransferase (GAMT) deficiency is an autosomal recessive genetic disorder which results in global developmental delay and intellectual disability. There is evidence that early treatment prevents intellectual disability and seizures. GAMT deficiency is now being discussed as a potential addition to the U.S. Recommended Uniform Screening Panel (RUSP); the availability of suitable screening methods must be considered. A neonatal screening derivatized method to quantify creatine (CRE) and guanidinoacetic acid (GAA) in dried blood spots by tandem mass spectrometry (MS/MS) has been described. Its key feature is the ability to detect CRE and GAA in the same extract generated from neonatal dried blood spots (DBS’s) during amino acids (AA) and acylcarnitines (AC) analysis. More laboratories are adopting non-derivatized MS/MS screening methods. We describe an improved, non-derivatized DBS extraction and MS/MS analytical method (AAAC-GAMT) that incorporates quantitation of CRE and GAA into routine analysis of amino acids, acylcarnitines, and succinylacetone. The non-derivatized AAAC-GAMT method performs comparably to the stand-alone GAMT and non-derivatized AAAC screening methods, supporting its potential suitability for high-throughput GAMT neonatal screening. Full article

The practice of newborn screening has been in place in the USA since the 1960s, with individual states initially screening for different numbers of disorders. In the early 2000s many efforts were made to standardize the various disorders being screened. Currently, there are at least 34 disorders that each state is mandated to include on their screening panel. Of those 34 disorders, the majority are inborn errors of metabolism (IEM) which include urea cycle disorders (UCD), citrullinemia (CIT) and argininosuccinic aciduria (ASA), as well as a number of fatty acid oxidation disorders. We present here four cases of infants who had critical newborn screens (NBS) in the Commonwealth of Virginia and underwent genetic testing because their clinical presentation and follow-up laboratory studies were not consistent with the disorder that was flagged by NBS. These newborns were found to be carriers for two different IEMs (in three cases) or compound heterozygotes (in one case). Currently no guidelines exist with respect to the appropriate way to manage these children who may or may not be symptomatic in the newborn period. We propose some general recommendations for management based on our experience with these four probands, and discuss the necessity for further conversation and collaboration between physicians encountering these not-so-infrequent presentations. Full article

The Perkin Elmer Genetic Screening Processor (GSP)™ is a fully automated system for the processing of immunoassays for thyroid stimulating hormone (TSH), 17-hydroxyprogesterone (17-OHP), immuno reactive trypsin (IRT), biotinidase, and total T4, as well as enzymatic assays for total galactose and galactose-1-phosphate uridyltransferase (GALT) from dried blood spots (DBS). The system however, has one drawback: it cannot transfer samples from one microtiter plate to another. While this is not a problem for immunoassays, it makes enzymatic assays more problematic. The remaining DBS can either cause significant signal quenching, or they can increase fluorescence intensity, when the DBS are floating on the surface. The latter can cause false negative results, when GALT is measured for galactosaemia screening. To overcome this problem, an additional measurement step to check for floating disks is incorporated, leading to prevention of the affected measurements. However, this causes a secondary problem in this totally closed system. We detected floating disk signals in approx. 0.7% of all screening samples as well as quality control samples, which had to be repeated. We describe a simple method, which is just a re-measurement on a victor fluorescence reader, or any other plate fluorimeter, with filters for excitation wavelength 340 nm, and emission wavelength 405 nm. The introduction of this second-tier measurement made all repeat measurements unnecessary. Full article

Urea cycle disorders (UCDs) are common inborn errors of metabolism, with an incidence of one in 30,000 births. They are caused by deficiencies in any of six enzymes and two carrier proteins, the most common being Ornithine Transcarbamylase Deficiency (OTCD). OTCD results in impairment to excrete nitrogen, causing toxic buildup of ammonia with resultant encephalopathy. Hyperammonemia (HA) induces the conversion of glutamate to glutamine in the brain. Excess glutamine in the brain causes osmotic changes, cerebral edema, changes in astrocyte morphology, and cell death. Acute symptoms of HA include vomiting, hyperventilation, seizures, and irritability. Long-term neurological effects include deficits in working memory and executive function. To date, there are no predictors of prognosis of infants with neonatal onset OTCD outside of the plasma ammonia level at presentation and duration of a hyperammonemic coma. We provide a comprehensive analysis of a 16-year-old male with neonatal onset of OTCD as an example of how brain biomarkers may be useful to monitor disease course and outcome. This male presented at 8 days of life with plasma ammonia and glutamine of 677 and 4024 micromol/L respectively, and was found to have a missense mutation in Exon 4 (p. R129H). Treatment included protein restriction, sodium benzoate, and citrulline, arginine, and iron. Despite compliance, he suffered recurrent acute hyperammonemic episodes triggered by infections or catabolic stressors. We discuss the long-term effects of the hyperammonemic episodes by following MRI-based disease biomarkers. Full article

Biotinidase deficiency is an inherited metabolic disorder that, if untreated, can result in neurological and cutaneous symptoms. If treated with the vitamin biotin, individuals with the disorder can markedly improve, but still may have some irreversible problems if therapy is delayed. If treated at birth, biotin therapy can prevent the development of symptoms as indicated by long-term outcomes. Therefore, the disorder readily meets the major criteria for newborn screening. Our laboratory has been instrumental in developing, piloting and establishing newborn screening for the disorder in the United States and in many countries. This review discusses some of the “behind-the-scenes” aspects of how we spread the word about the disorder and what we learned from over 30 years of newborn screening. We also discuss some of the controversies and issues about biotinidase deficiency that remain to be addressed. Based on the successful outcomes of older adolescents and adults with profound biotinidase deficiency identified by newborn screening, this is one of the best, if not the best, disorder for which to perform newborn screening. In summary, “If an individual has to have an inherited metabolic disorder, biotinidase deficiency is the one to have.” Full article

The objective of this study was to evaluate the MBJ20^® transcutaneous bilirubinonometer by Beijing M&B Electronic Instrument Co. Ltd. (Beijing, China) in the assessment of severity of neonatal jaundice. Two hundred and twenty-two paired samples from 88 newborns aged between 28 and 44 weeks of gestation at Nnamdi Azikiwe University Teaching Hospital, Nnewi Anambra State, were analyzed. These infants had total serum bilirubin (TSB) levels measured on clinical indication, and transcutaneous bilirubin (TcB) levels were obtained at the forehead and sternum within 10 min of the TSB levels. There was a close correlation between TSB and TcBF and between TSB and TcBS for all the paired readings (n = 222, r = 0.904; n = 222, r = 0.917, respectively). MBJ20 values differed on average from the TSB values by 3.2 mg/dL for TcBF and 2.0 mg/dL for TcBs. We conclude that TcB measurements using the MBJ20 jaundice meter correlate very closely with TSB levels over the range of TSB encountered in this study and that estimation of TcB should be done at both the forehead and sternum. Full article