Newborn screening system: Safety, technology, advocacy

Newborn screening (NBS) is more than 50 years old and has proven to be a powerful and successful public health system. NBS must be regarded as a system and not simply as a test. We need to work as a community to improve the culture of safety for the NBS system and thereby to reduce the risk of babies being missed by the NBS system. Adding new technologies will not prevent system failures; that will require adherence to the culture of safety. Some have argued that every newborn should have their genome sequenced at birth and this sequencing could be part of NBS. However, NBS has depended on biomarker phenotypes throughout its history and our understanding of the relationships between genotype and phenotype is imperfect. Therefore, we should avoid being seduced by genomic sequencing technology and continue to focus on phenotypic biomarkers in NBS.

The mediating effects of public genomic knowledge in precision medicine implementation: A structural equation model approach

Precision medicine emphasizes predictive, preventive and personalized treatment on the basis of information gleaned from personal genetic and environmental data. Its implementation at health systems level is regarded as multifactorial, involving variables associated with omics technologies, public genomic awareness and adoption tendencies for new medical technologies. However, interrelationships of the various factors and their synergy has not been sufficiently quantified. Based on a survey of 270 participants involved in the use of molecular tests (omics-based biomarkers, OBMs), this study examined how characteristics of omics biomarkers influence precision medicine implementation outcomes (ImO) through an intermediary factor, public genomic awareness (represented by User Response, UsR). A structural equation modelling (SEM) approach was applied to develop and test a 3 latent variable mediation model; each latent variable being measured by a set of indicators ranging between three and six. Mediation analysis results confirmed a partial mediation effect (an indirect effect represented as the product of paths 'a' and 'b' (a*b)) of 0.36 at 90% confidence level, CI = [0.03, 9.94]. Results from the individual mediation paths 'a' and 'b' however, showed that these effects were negative(a = -0.38, b = -0.94). Path 'a' represents the effect of characteristics of OBMs on the mediator, UsR; 'b' represents the effect of the mediator, UsR on implementation outcomes, ImO, holding OBMs constant. The results have both theoretical and practice implications for biomedical genomics research and clinical genomics, respectively. For instance, the results imply better ways have to be devised to more effectively engage the public in addressing extended family support for extended family cascade screening, especially for monogenic hereditary conditions like BRCA-related breast cancer and colorectal cancer in Lynch syndrome families. At basic biomedical research level, results suggest an integrated biomarker development pipeline, with early consideration of factors that may influence biomarker uptake. The results are also relevant at health systems level in indicating which factors should be addressed for successful.

Metabolic Serendipities of Expanded Newborn Screening

Incidental findings on newborn screening (NBS) are results that are not the target of screening within a given NBS program, but rather are found as a result of the screening and resulting diagnostic workup for that target. These findings may not have an immediate clinical impact on the newborn, but are sometimes an additional benefit of NBS programs and may be considered secondary targets of NBS programs. This work describes four case reports that had incidental findings on the NBS, which eventually led to the diagnosis of another metabolic disease instead of the one that was initially suspected. The first case was a new defect in the cationic amino acid transporter-2 (CAT-2), which was oriented as an arginase-1 deficiency in the newborn. The second case was a maternal glutaric aciduria type 1 (GA-1) that mimicked a carnitine transporter deficiency in the newborn. The third report was a case of lysinuric protein intolerance (LPI), which appeared as high levels of citrulline on the NBS. The fourth case was a mother with homocystinuria that was diagnosed during the biochemical study of vitamin B₁₂ status. All cases provide new or interesting data that will help guide differential diagnosis in the future.

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

OBJECTIVES

Contrary to many western European countries, most south-eastern European countries do not have an expanded newborn screening (NBS) program using tandem mass spectrometry. This study would represent one of the first expanded NBS studies in south-eastern Europe and will enable the estimation of the incidences of IEM in Slovenia. We proposed an expanded NBS approach including next-generation sequencing (NGS) as a confirmational analysis.

DESIGN & METHODS

We conducted a pilot study of expanded NBS for selected inborn errors of metabolism (IEM) in Slovenia including 10,048 NBS cards. We used an approach including tandem mass spectrometry followed by second tier tests including NGS. Based on the NBS results, 85 children were evaluated at a metabolic follow-up; 80 of them were analyzed using NGS.

RESULTS

Altogether, glutaric acidemia type 1 was confirmed in one patient who was a compound heterozygote for two known causative GCDH variants. A patient with suspected very long-chain acyl-CoA dehydrogenase deficiency had negative metabolic follow-up tests, but had two heterozygous ACADVL variants; one known disease-causing variant and one indel, namely c.205-8_205-7delinsGC, that is predicted to be causative. Nine participants had elevated metabolites characteristic of 3-methylcrotonyl-CoA carboxylase deficiency, 2 of them had known causative homozygous variants in MCCC1. The other seven were heterozygous; two had a novel genetic variant c.149_151dupCCA (p.Thr50dup). Cumulative incidences of IEM in Slovenia were similar to other European countries.

CONCLUSIONS

NGS proved to be valuable in explaining the abnormal metabolite concentrations in NBS as it enabled the differentiation between affected patients and mere heterozygotes, and it improved the turnaround time of genetic analysis. The results of this study will be instrumental in the routine implementation of expanded NBS in Slovenia.

Expanded Newborn Screening: Challenges to NICU Nurses

BACKGROUND

Newborn screening programs provide testing for all newborns born in this country for conditions that can potentially cause death or disability. Currently each state is responsible for its programs and the number of disorders screened varies from state to state. The current universal recommended metabolic screening panel may include 32 to 58 disorders. Expansion of the programs has impacted the role of nurses in the neonatal intensive care units (NICUs). Nurses are responsible for facilitating the screening process, educating the family, and assisting with follow-up. In addition, they are the first-line defense for emotional, spiritual, and social support.

PURPOSE

To review of the expansion of this program over time and discuss challenges the NICU nurse encounters.

METHODS/SEARCH STRATEGY

Research literatures along with the national recommendation by governmental and professional agencies were reviewed to obtain evidence on current practice recommendations.

FINDINGS/RESULTS/IMPLICATIONS FOR PRACTICE AND RESEARCH

NICU nurses face several challenges with the expansion of newborn screening programs. This includes gaining knowledge to answer questions posed by empowered parents and educate them appropriately; ensuring quality of the process that minimizes errors and optimal communication; and, addressing ethical concerns about the storage and subsequent use of specimens. New and ongoing research can measure and ensure provision of quality services provided through the NICUs globally.

Long-term outcome of expanded newborn screening at Boston children's hospital: benefits and challenges in defining true disease

INTRODUCTION

There is no universal consensus of the disorders included in newborn screening programs. Few studies so far, mostly short-term, have compared the outcome of disorders detected by expanded newborn screening (ENBS) to the outcome of the same disorders detected clinically.

METHODS

We compared the clinical and neurodevelopmental outcomes in patients with metabolic disorders detected by ENBS, including biotinidase testing, with those detected clinically and followed at the Metabolism Clinic at Boston Children's Hospital.

RESULTS

One hundred eighty-nine patients came to attention from ENBS and 142 were clinically diagnosed. 3-methylcrotonyl-CoA carboxylase, biotinidase, and carnitine deficiencies were exclusively identified by ENBS and medium chain acyl-CoA dehydrogenase (MCADD) and very long chain acyl-CoA dehydrogenase deficiencies (VLCADD) were predominantly identified by ENBS whereas the organic acid disorders more often came to attention clinically. Only 2% of the ENBS-detected cases had clinically severe outcomes compared to 42% of those clinically detected. The mean IQ score was 103 + 17 for the ENBS-detected cases and 77 + 24 for those clinically detected. Those newly included disorders that seem to derive the greatest benefit from ENBS include the fatty acid oxidation disorders, profound biotinidase deficiency, tyrosinemia type 1, and perhaps carnitine deficiency.

CONCLUSION

Although the NBS-identified and clinically-identified cohorts were not completely comparable, this long-term study shows likely substantial improvement overall in the outcome of these metabolic disorders in the NBS infants. Infants with mild disorders and benign variants may represent a significant number of infants identified by ENBS. The future challenge will be to unequivocally differentiate the disorders most benefitting from ENBS and adjust programs accordingly.

Newborn screening and the era of medical genomics

Across the span of the last 75+ years, technological and conceptual advances in genetics have found rapid implementation at the beginning of human life. From karyotype testing, to molecular cytogenetics, to gene panel testing, and now to whole exome and whole genome sequencing, each iterative expansion of our capability to acquire genetic data on the next generation has been implemented quickly in the clinical setting. In tandem, our continuously expanding ability to acquire large volumes of genetic data has generated its own challenges in terms of interpretation, clinical utility of the information, and concerns over privacy and discrimination; for the first time, we are faced with the possibility of having complete access to our genetic data from birth, if not shortly after conception. Here, we discuss the evolution of the field toward this new reality and we consider the potentially far-reaching consequences and, at present, an unclear path toward developing best practices for implementation.

Showing Value in Newborn Screening: Challenges in Quantifying the Effectiveness and Cost-Effectiveness of Early Detection of Phenylketonuria and Cystic Fibrosis

Decision makers sometimes request information on the cost savings, cost-effectiveness, or cost-benefit of public health programs. In practice, quantifying the health and economic benefits of population-level screening programs such as newborn screening (NBS) is challenging. It requires that one specify the frequencies of health outcomes and events, such as hospitalizations, for a cohort of children with a given condition under two different scenarios-with or without NBS. Such analyses also assume that everything else, including treatments, is the same between groups. Lack of comparable data for representative screened and unscreened cohorts that are exposed to the same treatments following diagnosis can result in either under- or over-statement of differences. Accordingly, the benefits of early detection may be understated or overstated. This paper illustrates these common problems through a review of past economic evaluations of screening for two historically significant conditions, phenylketonuria and cystic fibrosis. In both examples qualitative judgments about the value of prompt identification and early treatment to an affected child were more influential than specific numerical estimates of lives or costs saved.

Newborn screening: A complex system that requires a culture of safety

As health care providers and organizations, we have a responsibility to examine our practices and systems for opportunities to improve quality and health outcomes. Today a critical opportunity exists in the newborn screening (NBS) system, which touches every one of the approximately 4 million babies born annually in the United States. This opportunity involves improving the quality of NBS by developing a culture of safety to prevent errors that in NBS represent missed babies and preventable morbidity and mortality. This commentary will explore the "culture of safety" for NBS, including the high reliability organization (HRO) paradigm and normal accident theory (NAT), which have been effective in reducing systems failures in other complex environments.

Novel heparan sulfate assay by using automated high-throughput mass spectrometry: Application to monitoring and screening for mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are caused by deficiency of one of a group of specific lysosomal enzymes, resulting in excessive accumulation of glycosaminoglycans (GAGs). We previously developed GAG assay methods using liquid chromatography tandem mass spectrometry (LC-MS/MS); however, it takes 4-5 min per sample for analysis. For the large numbers of samples in a screening program, a more rapid process is desirable. The automated high-throughput mass spectrometry (HT-MS/MS) system (RapidFire) integrates a solid phase extraction robot to concentrate and desalt samples prior to direction into the MS/MS without chromatographic separation; thereby allowing each sample to be processed within 10s (enabling screening of more than one million samples per year). The aim of this study was to develop a higher throughput system to assay heparan sulfate (HS) using HT-MS/MS, and to compare its reproducibility, sensitivity and specificity with conventional LC-MS/MS. HS levels were measured in the blood (plasma and serum) from control subjects and patients with MPS II, III, or IV and in dried blood spots (DBS) from newborn controls and patients with MPS I, II, or III. Results obtained from HT-MS/MS showed 1) that there was a strong correlation of levels of disaccharides derived from HS in the blood, between those calculated using conventional LC-MS/MS and HT-MS/MS, 2) that levels of HS in the blood were significantly elevated in patients with MPS II and III, but not in MPS IVA, 3) that the level of HS in patients with a severe form of MPS II was higher than that in an attenuated form, 4) that reduction of blood HS level was observed in MPS II patients treated with enzyme replacement therapy or hematopoietic stem cell transplantation, and 5) that levels of HS in newborn DBS were elevated in patients with MPS I, II or III, compared to those of control newborns. In conclusion, HT-MS/MS provides much higher throughput than LC-MS/MS-based methods with similar sensitivity and specificity in an HS assay, indicating that HT-MS/MS may be feasible for diagnosis, monitoring, and newborn screening of MPS.

Inborn errors of metabolism and expanded newborn screening: review and update

Inborn errors of metabolism (IEM) are a phenotypically and genetically heterogeneous group of disorders caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites. To date, more than 1000 different IEM have been identified. While individually rare, the cumulative incidence has been shown to be upwards of 1 in 800. Clinical presentations are protean, complicating diagnostic pathways. IEM are present in all ethnic groups and across every age. Some IEM are amenable to treatment, with promising outcomes. However, high clinical suspicion alone is not sufficient to reduce morbidities and mortalities. In the last decade, due to the advent of tandem mass spectrometry, expanded newborn screening (NBS) has become a mandatory public health strategy in most developed and developing countries. The technology allows inexpensive simultaneous detection of more than 30 different metabolic disorders in one single blood spot specimen at a cost of about USD 10 per baby, with commendable analytical accuracy and precision. The sensitivity and specificity of this method can be up to 99% and 99.995%, respectively, for most amino acid disorders, organic acidemias, and fatty acid oxidation defects. Cost-effectiveness studies have confirmed that the savings achieved through the use of expanded NBS programs are significantly greater than the costs of implementation. The adverse effects of false positive results are negligible in view of the economic health benefits generated by expanded NBS and these could be minimized through increased education, better communication, and improved technologies. Local screening agencies should be given the autonomy to develop their screening programs in order to keep pace with international advancements. The development of biochemical genetics is closely linked with expanded NBS. With ongoing advancements in nanotechnology and molecular genomics, the field of biochemical genetics is still expanding rapidly. The potential of tandem mass spectrometry is extending to cover more disorders. Indeed, the use of genetic markers in T-cell receptor excision circles for severe combined immunodeficiency is one promising example. NBS represents the highest volume of genetic testing. It is more than a test and it warrants systematic healthcare service delivery across the pre-analytical, analytical, and post-analytical phases. There should be a comprehensive reporting system entailing genetic counselling as well as short-term and long-term follow-up. It is essential to integrate existing clinical IEM services with the expanded NBS program to enable close communication between the laboratory, clinicians, and allied health parties. In this review, we will discuss the history of IEM, its clinical presentations in children and adult patients, and its incidence among different ethnicities; the history and recent expansion of NBS, its cost-effectiveness, associated pros and cons, and the ethical issues that can arise; the analytical aspects of tandem mass spectrometry and post-analytical perspectives regarding result interpretation.

Adult genetic risk screening

Recent advances in genetic analysis especially DNA sequencing technology open a new strategy for adult disease prevention by genetic screening. Physicians presently treat disease pathology with less emphasis on disease risk prevention/reduction. Genetic screening has reduced the incidence of untreatable childhood genetic diseases and improved the care of newborns. The opportunity exists to expand screening programs and reduce the incidence of adult onset diseases via genetic risk identification and disease intervention. This article outlines the approach, challenges, and benefits of such screening for adult genetic disease risks.

Newborn screening and diagnosis of mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are caused by deficiency of lysosomal enzyme activities needed to degrade glycosaminoglycans (GAGs), which are long unbranched polysaccharides consisting of repeating disaccharides. GAGs include: chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and hyaluronan. Their catabolism may be blocked singly or in combination depending on the specific enzyme deficiency. There are 11 known enzyme deficiencies, resulting in seven distinct forms of MPS with a collective incidence of higher than 1 in 25,000 live births. Accumulation of undegraded metabolites in lysosomes gives rise to distinct clinical syndromes. Generally, the clinical conditions progress if untreated, leading to developmental delay, systemic skeletal deformities, and early death. MPS disorders are potentially treatable with enzyme replacement therapy or hematopoietic stem cell transplantation. For maximum benefit of available therapies, early detection and intervention are critical. We recently developed a novel high-throughput multiplex method to assay DS, HS, and KS simultaneously in blood samples by using high performance liquid chromatography/tandem mass spectrometry for MPS. The overall performance metrics of HS and DS values on MPS I, II, and VII patients vs. healthy controls at newborns were as follows using a given set of cut-off values: sensitivity, 100%; specificity, 98.5-99.4%; positive predictive value, 54.5-75%; false positive rate, 0.62-1.54%; and false negative rate, 0%. These findings show that the combined measurements of these three GAGs are sensitive and specific for detecting all types of MPS with acceptable false negative/positive rates. In addition, this method will also be used for monitoring therapeutic efficacy. We review the history of GAG assay and application to diagnosis for MPS.

Expanded newborn screening and confirmatory follow-up testing for inborn errors of metabolism detected by tandem mass spectrometry

Newborn screening (NBS) of inborn errors of metabolism (IEM) is a coordinated comprehensive system consisting of education, screening, follow-up of abnormal test results, confirmatory testing, diagnosis, treatment, and evaluation of periodic outcome and efficiency. The ultimate goal of NBS and follow-up programs is to reduce morbidity and mortality from the disorders. Over the past decade, tandem mass spectrometry (MS/MS) has become a key technology in the field of NBS. It has replaced classic screening techniques of one-analysis, one-metabolite, one-disease with one analysis, many-metabolites, and many-diseases. The development of electrospray ionization (ESI), automation of sample handling and data manipulation have allowed the introduction of expanded NBS for the identification of numerous conditions on a single sample and new conditions to be added to the list of disorders being screened for using MS/MS. In the case of a screened positive result, a follow-up analytical test should be performed for confirmation of the primary result. The most common confirmatory follow-up tests are amino acids and acylcarnitine analysis in plasma and organic acid analysis in urine. NBS should be integrated with follow-up and clinical management. Recent improvements in therapy have caused some disorders to be considered as potential candidates for NBS. This review covers some of the basic theory of expanded MS/MS and follow-up confirmatory tests applied for NBS of IEM.

Bezafibrate can be a new treatment option for mitochondrial fatty acid oxidation disorders: evaluation by in vitro probe acylcarnitine assay

BACKGROUND

The number of patients with mitochondrial fatty acid oxidation (FAO) disorders is recently becoming larger with the spread of newborn mass screening. Despite the advances in metabolic and molecular characterization of FAO disorders, the therapeutic studies are still limited. It was reported recently that bezafibrate (BEZ), an agonist of peroxisome proliferating activator receptor (PPAR), can restore FAO activity in cells from carnitine palmitoyltransferase-2 (CPT2) and very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiencies as well as clinical symptoms in the adult patients.

METHODS

In this study, the therapeutic effect of BEZ was determined by in vitro probe acylcarnitine (IVP) assay using cultured fibroblasts and tandem mass spectrometry on various FAO disorders. The clinical trial of BEZ treatment for a boy with the intermediate form of glutaric acidemia type 2 (GA2) was also performed.

RESULTS

The effect of BEZ was proven in cells from various FAO disorders including GA2, deficiencies of VLCAD, medium-chain acyl-CoA dehydrogenase, CPT2, carnitine acylcarnitine translocase and trifunctional protein, by the IVP assay. The aberrantly elevated long- or medium-chain acylcarnitines that are characteristic for each FAO disorder were clearly corrected by the presence of BEZ (0.4 mmol/L) in culture medium. Moreover, daily administration of BEZ in a 2-year-old boy with GA2 dramatically improved his motor and cognitive skills, accompanied by sustained reduction of C4, C8, C10 and C12 acylcarnitines in blood, and normalized the urinary organic acid profile. No major adverse effects have been observed.

CONCLUSION

These results indicate that BEZ could be a new treatment option for FAO disorders.

The emergence of translational epidemiology: from scientific discovery to population health impact

Recent emphasis on translational research (TR) is highlighting the role of epidemiology in translating scientific discoveries into population health impact. The authors present applications of epidemiology in TR through 4 phases designated T1-T4, illustrated by examples from human genomics. In T1, epidemiology explores the role of a basic scientific discovery (e.g., a disease risk factor or biomarker) in developing a "candidate application" for use in practice (e.g., a test used to guide interventions). In T2, epidemiology can help to evaluate the efficacy of a candidate application by using observational studies and randomized controlled trials. In T3, epidemiology can help to assess facilitators and barriers for uptake and implementation of candidate applications in practice. In T4, epidemiology can help to assess the impact of using candidate applications on population health outcomes. Epidemiology also has a leading role in knowledge synthesis, especially using quantitative methods (e.g., meta-analysis). To explore the emergence of TR in epidemiology, the authors compared articles published in selected issues of the Journal in 1999 and 2009. The proportion of articles identified as translational doubled from 16% (11/69) in 1999 to 33% (22/66) in 2009 (P = 0.02). Epidemiology is increasingly recognized as an important component of TR. By quantifying and integrating knowledge across disciplines, epidemiology provides crucial methods and tools for TR.

Nanopediatrics: enabling personalized medicine for children

The topic of the special series of reviews in this issue will be nanobiology and nanomedicine, with a focus on the impact of nanotechnology on children and their health; hence, the title of this collection and this introduction, Nanopediatrics: Enabling Personalized Medicine for Children. We will address what is meant when we discuss these nanodisciplines and why we developed a NanoPediatrics Program at University of California, Los Angeles. We will consider the implications of these nanodisciplines for individuals and society. The nature of research, diagnosis, and screening in nanomedicine and nanopediatrics will be illustrated by selected projects in nanodiagnostics and nanotherapeutics by our group and our collaborators, and the combined use of diagnostics and therapeutics in a single nanodevice referred to as "theranostics." We will conclude this introductory review with a summary of the reasons for developing the discipline of nanopediatrics.

Inborn Errors of Metabolism: the metabolome is our world. Presidential address for the 11th International Congress of Inborn Errors of Metabolism (ICIEM)

Thank you for honoring me by allowing me to serve as president of the 11th International Congress of Inborn Errors of Metabolism (ICIEM). The science brought by the IEM community to the Congress was quite impressive and demonstrated the quality of research within this community. In this address, I will consider briefly the history of IEMs to determine how we have arrived where we are, and will spend more time ascertaining our place in the current biomedical community and our role in determining the future of personalized medicine. In the 1950s-1970s new tools were added to expand our ability to interrogate the metabolome and the result was an explosive increase in the number of IEMs. This set the stage for expanded newborn screening (NBS) by tandem mass spectrometry (MS/MS) to identify these patients and to intervene pre-symptomatically. The complexity of the metabolome has led us to utilize the mathematical algorithms of systems biology to reduce high dimensionality data to low dimensionality output. However, the metabolome does not exist in isolation and we must learn how to integrate the metabolome with other xomics. The metabolome is our world and the IEM community has much to share with the broader xomics communities by integrating what we have learned with the other xomics communities. They are seeking access to the metabolome as a closer measure of phenotype, and we are already extremely comfortable and competent in the metabolomic space. But we should not be insular in our occupation of this space. NBS should be the model for personalized medicine, because it is already functioning as testing system for predictive, preventive and personalized care. We have been working in the area of NBS for nearly a half century and have many lessons learned that will be valuable to the practitioners of personalized medicine - lessons that they should not have to rediscover. We must embrace the international IEM community to meet population trends and to improve the care for individuals - children and adults - with IEMs. Demographic projections indicate the countries with largest population growth during the next four decades will be in Asia and we need to work collaboratively to build capacity in the IEM community in Asia and beyond to other underserved regions of the world.

[Genetic testing in the context of the revision of the French law on bioethics]

This article focuses on six questions raised by genetic testing in human: (1) the use of genetic tests, (2) information given to relatives of patients affected with genetic disorders, (3) prenatal and preimplantatory diagnosis for late onset genetic diseases and the use of pangenomic tests in prenatal diagnosis, (4) direct-to-consumer genetic testing, (5) population screening in the age of genomic medicine and (6) incidental findings when genetic testing are used.

Development of a routine newborn screening protocol for severe combined immunodeficiency

BACKGROUND

Severe combined immunodeficiency (SCID) is characterized by the absence of functional T cells and B cells. Without early diagnosis and treatment, infants with SCID die from severe infections within the first year of life.

OBJECTIVE

To determined the feasibility of detecting SCID in newborns by quantitating T-cell receptor excision circles (TRECs) from dried blood spots (DBSs) on newborn screening (NBS) cards.

METHODS

DNA was extracted from DBSs on deidentified NBS cards, and real-time quantitative PCR (RT-qPCR) was used to determine the number of TRECs. Positive controls consisted of DBS from a 1-week-old T(-)B(-)NK(+) patient with SCID and whole blood specimens selectively depleted of naive T cells.

RESULTS

The mean and median numbers of TRECs from 5766 deidentified DBSs were 827 and 708, respectively, per 3.2-mm punch ( approximately 3 muL whole blood). Ten samples failed to amplify TRECs on initial analysis; all but 1 demonstrated normal TRECs and beta-actin amplification on retesting. No TRECs were detected in either the SCID or naive T-cell-depleted samples, despite the presence of normal levels of beta-actin.

CONCLUSIONS

The use of RT-qPCR to quantitate TRECs from DNA extracted from newborn DBSs is a highly sensitive and specific screening test for SCID. This assay is currently being used in Wisconsin for routine screening infants for SCID.

Challenges and developments in tandem mass spectrometry based clinical metabolomics

'Clinical metabolomics' aims at evaluating and predicting health and disease risk in an individual by investigating metabolic signatures in body fluids or tissues, which are influenced by genetics, epigenetics, environmental exposures, diet, and behaviour. Powerful analytical techniques like liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) offers a rapid, effective and economical way to analyze metabolic alterations of pre-defined target metabolites in biological samples. Novel hyphenated technical approaches like the combination of tandem mass spectrometry combined with linear ion trap (QTrap mass spectrometry) combines both identification and quantification of known and unknown metabolic targets. We describe new concepts and developments of mass spectrometry based multi-target metabolome profiling in the field of clinical diagnostics and research. Particularly, the experiences from newborn screening provided important insights about the diagnostic potential of metabolite profiling arrays and directs to the clinical aim of predictive, preventive and personalized medicine by metabolomics.

The emerging role of primary care in genetics

PURPOSE OF REVIEW

Advances in genetics are occurring at a rapid pace. It will ultimately be the primary care pediatrician who assimilates this knowledge and applies it to patient care. This article is written in a patient encounter format with which the pediatrician is familiar. The vignettes are from the author's own experiences in 13 years of general pediatric practice.

RECENT FINDINGS

The current literature reinforces the idea that changes in the complexity of the diagnostic evaluation and the time spent explaining the recommended testing will be required by the pediatrician. With this responsibility comes the need of new training strategies for medical students and established pediatricians.

SUMMARY

Pediatricians will be called upon to incorporate new genetic findings into patient care. This task will ultimately be no different than it was for past pediatricians to incorporate new immunizations or antibiotics into the care plan for each patient. Patient care will improve because therapy will be tailor-made for both the disease and the patient.

Gene therapy for inborn errors of liver metabolism: progress towards clinical applications

The treatment for inborn errors of liver metabolism is based on dietary, drug, and cell therapies (orthotopic liver transplantation). However, significant morbidity and mortality still remain, and alternative strategies are needed. Gene replacement therapy has the potential of providing a definitive cure for patients with these diseases. Significant progress has been made in the pre-clinical arena and achievement of efficacy in different animal models has been reported using multiple gene transfer technologies. This article summarizes the gene transfer strategies being investigated, the pre-clinical data, and the available early clinical results for inborn errors of liver metabolism.

Pharmacology and genetics of autism: implications for diagnosis and treatment

Autism has the highest estimated heritability (>90%) among behaviorally defined neuropsychiatric disorders. Rapidly advancing genomic technologies and large international collaborations have increased our understanding of the molecular genetic causes of autism. Pharmacogenomic approaches are currently being applied in two single-gene disorders, fragile X syndrome and Rett syndrome, which capture many aspects of the autistic phenotype. This review describes the current state of the genetics of autism and suggests how to extend pharmacological principles pioneered in fragile X and Rett to the broader group of patients with autism.