Ment Retard Dev Disabil Res Rev
· 2007 · PMID 17326110
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Fragile X syndrome (FXS) is the leading inherited cause of mental retardation. In this article, we review what is known about the language and related problems of individuals with FXS. In doing so, we focus on the syndro...Fragile X syndrome (FXS) is the leading inherited cause of mental retardation. In this article, we review what is known about the language and related problems of individuals with FXS. In doing so, we focus on the syndrome-specific features of the language phenotype and on the organismic (i.e., genetic and individual neurocognitive and behavioral) and environmental factors associated with within-syndrome variation in the phenotype. We also briefly review those aspects of the behavioral phenotype of FXS that are relevant for understanding syndrome-specific features of, and within-syndrome variability in, language. The review includes summaries of research on the prelinguistic foundations for language development and on each of the major components of language (i.e., vocabulary, morphosyntax, and pragmatics). Throughout the review, we point out implications of existing research for intervention as well as directions for future research.
Ment Retard Dev Disabil Res Rev
· 2007 · PMID 17326109
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Williams syndrome, a genetic disorder caused by a microdeletion of approximately 25 genes on chromosome 7q11.23, is associated with mild to moderate intellectual disability or learning difficulties. Most individuals with...Williams syndrome, a genetic disorder caused by a microdeletion of approximately 25 genes on chromosome 7q11.23, is associated with mild to moderate intellectual disability or learning difficulties. Most individuals with Williams syndrome evidence a cognitive profile including relative strengths in verbal short-term memory and language, and considerable weakness in visuospatial construction. The syndrome has often been argued to provide strong evidence for the independence of language from other aspects of cognition. We provide a brief history of early research on the language abilities of individuals with Williams syndrome and then review contemporary studies of language and cognition in Williams syndrome, beginning with a consideration of performance on standardized assessments. In the remainder of the article, we first consider early language acquisition, with a focus on speech production and perception, vocabulary acquisition, and communicative/pragmatic development and then consider the language abilities of school-age children and adolescents, focusing on semantics, grammar, and pragmatics. We argue that rather than being the paradigm case for the independence of language from cognition, Williams syndrome provides strong evidence of the interdependence of many aspects of language and cognition.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183579
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Expanded newborn screening programs and subsequent detection of rare genetic disorders challenge parents and their medical providers to learn about the treatment and management of these disorders. Many people seek medica...Expanded newborn screening programs and subsequent detection of rare genetic disorders challenge parents and their medical providers to learn about the treatment and management of these disorders. Many people seek medical information on the Internet but may encounter requests for registration or fees, or find that resources are out of date, difficult to understand, or buried in advertisements. The U.S. National Library of Medicine (NLM), a component of the National Institutes of Health, provides web-based resources that address the challenges of newborn screening education. These resources include MedlinePlus, Genetics Home Reference, ClinicalTrials.gov, and PubMed. NLM websites are not commercial, do not require registration or fees, and provide varied levels of information for a continuum of audiences from low-literacy consumers to health professionals. Using phenylketonuria as an example, this study describes the information that parents and their medical providers can find through NLM resources. NLM has embraced the digital age and provides the public with reliable, accurate, and up-to-date educational materials.
Puryear M, Weissman G, Watson M
… +3 more, Mann M, Strickland B, van Dyck PC
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183578
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Newborn screening and genetic technologies are expanding and changing rapidly, increasing the demand for genetic specialty services. Because of the scarcity and geographic maldistribution of genetic specialty services, a...Newborn screening and genetic technologies are expanding and changing rapidly, increasing the demand for genetic specialty services. Because of the scarcity and geographic maldistribution of genetic specialty services, access to these services is a critical issue. This article discusses some of the efforts initiated by the Maternal and Child Health Bureau of the Health Resources and Services Administration, particularly the establishment of regional genetic and newborn screening collaboratives to improve access to these services and expertise.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183577
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Expansion of newborn screening (NBS) has been driven primarily by a combination of advances in technology and medical treatment, and the sustained advocacy efforts of consumers and voluntary health organizations. The lon...Expansion of newborn screening (NBS) has been driven primarily by a combination of advances in technology and medical treatment, and the sustained advocacy efforts of consumers and voluntary health organizations. The longstanding leadership of the March of Dimes has been credited by many as a critical factor in the expansion and improvement of state NBS programs. From the historic vantage point of four decades of March of Dimes involvement with newborn screening, this report reviews the unique origin of the first newborn screening test, and identifies from this point of origin several of the elements which still define the evolution of advocacy for NBS today. It also documents activities at the federal level and in seven states that have lead to expanded screening for newborns. Advances in NBS technology and medical treatment have informed policy development. Mobilization of volunteers and focused advocacy activities have brought about expansion of screening opportunities for newborns across the United States. But more work is needed. Continued application of the effective strategies identified in this report will help assure that all families have the best possible chance of assuring that their newborns do not have to suffer the complications of conditions that we know can be treated effectively.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183576
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Universal newborn screening programs for metabolic disorders are typically described as a triumph of medicine and public policy in the US over the last 50 years. Advances in science and technology, including the Human Ge...Universal newborn screening programs for metabolic disorders are typically described as a triumph of medicine and public policy in the US over the last 50 years. Advances in science and technology, including the Human Genome Project, offer the opportunity to expand universal newborn screening programs to include many additional metabolic and genetic conditions. Although the benefits of such screening programs appear to outweigh their costs, some critics have claimed that historical examples of inadvertent harm ensuing from false-positive screening results and subsequent inappropriate medical treatment should make us wary of expanding universal newborn screening. In this essay, we report the results of a review of the published literature to assess whether the extension of screening from at risk populations to all newborns led to substantial morbidity and mortality from misguided medical treatment. We provide a historical overview of universal newborn screening programs in the United States, and then focus on six early NBS programs: congenital hypothyroidism, phenylketonuria, congenital adrenal hyperplasia, galactosemia, sickle cell disease, and maple syrup urine disease. Our comprehensive search of published sources did not reveal a widespread problem of harm ensuing from medical treatment of children with false positive screening test results.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183575
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Recent changes in genetics research have created new opportunities to improve the scope and quality of newborn screening services. Changes in newborn screening should be supported and directed by an organized program of...Recent changes in genetics research have created new opportunities to improve the scope and quality of newborn screening services. Changes in newborn screening should be supported and directed by an organized program of research. The NICHD Research Initiative in Newborn Screening includes the development of systematic methods to identify additional conditions appropriate for newborn screening; development and testing innovative interventions and treatments to improve outcomes; education of the provider workforce; development and implementation of appropriate information and communication systems for parents and providers; and, sponsoring an ongoing program of research and research training. Future needs will include the development of a national translational research infrastructure, prevention research and research into behavioral and social sciences issues. The NICHD Research Initiative in Newborn Screening is expected to be an ongoing and vital initiative that adapts itself to new scientific findings, technological developments, changes in the public and personal health care system, and our evolving understanding of the needs of affected individuals, families and the community.
Rinaldo P, Zafari S, Tortorelli S
… +1 more, Matern D
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183573
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The expansion of newborn screening programs to include multiplex testing by tandem mass spectrometry requires understanding and close monitoring of performance metrics. This is not done consistently because of lack of de...The expansion of newborn screening programs to include multiplex testing by tandem mass spectrometry requires understanding and close monitoring of performance metrics. This is not done consistently because of lack of defined targets, and interlaboratory comparison is almost nonexistent. Between July 2004 and April 2006 (N=176,185 cases), the overall performance metrics of the Minnesota program, limited to MS/MS testing, were as follows: detection rate 1:1,816, positive predictive value 37% (54% in 2006 till date), and false positive rate 0.09%. The repeat rate and the proportion of cases with abnormal findings actually been reported are new metrics proposed here as an objective mean to express the overall noise in a program, where noise is defined as the total number of abnormal results obtained using a given set of cut-off values. On the basis of our experience, we propose the following targets as evidence of adequate analytical and postanalytical performance: detection rate 1:3,000 or higher, positive predictive value>20%, and false positive rate<0.3%.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183572
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Newborn screening is considered a highly successful public health program that has resulted in the reduction of mortality, mental retardation, and other serious disabilities in thousands of children since the introductio...Newborn screening is considered a highly successful public health program that has resulted in the reduction of mortality, mental retardation, and other serious disabilities in thousands of children since the introduction of screening for phenylketonuria (PKU) in the 1960s. Programs are based in state public health departments such that each state independently reaches decisions as to which conditions should be mandated for inclusion in programs, leading to considerable variability among the states as to what is being screened. New technologies and knowledge of the genetics of many conditions have greatly expanded the number of conditions with potential for inclusion in newborn screening.
Pass K, Green NS, Lorey F
… +2 more, Sherwin J, Comeau AM
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183570
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The term "pilot study" has been used over the years to describe the evaluation of the many elements involved in deciding whether a proposed condition should be added to a newborn screening (NBS) panel, and until recently...The term "pilot study" has been used over the years to describe the evaluation of the many elements involved in deciding whether a proposed condition should be added to a newborn screening (NBS) panel, and until recently, was unilaterally used to describe the evaluation of the assay to be used before the condition was officially adopted by a state for its newborn screening panel. Since Guthrie's introduction of screening for PKU, each time a new condition was added to the panel, the screening assay itself was validated through a population-based trial, in which the test was performed with de-identified samples to avoid association between the test result and the infant. This is considered by the laboratory as the "pilot phase" of adding a new condition. To advance the science of NBS, especially to accommodate new technologies that may provide new types of information (genetic versus physiological) for each new condition, pilot programs are essential. Involvement of the clinical community serves to improve these evaluations and provides the needed clinical validation of decisions made as a result of it. This paper describes the historical context of pilot programs in population-based NBS that utilize laboratory-based markers as indicators of concern; specifically, three applications that demonstrate different approaches to the use of pilots in adding conditions to a NBS panel are described.
Bailey DB, Beskow LM, Davis AM
… +1 more, Skinner D
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183569
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The likelihood of benefit is fundamental to decision making about newborn screening. But benefit is construed in different ways by different stakeholders. This article begins with a review of benefit as considered histor...The likelihood of benefit is fundamental to decision making about newborn screening. But benefit is construed in different ways by different stakeholders. This article begins with a review of benefit as considered historically by various expert panels and organizations. We then show how 78 conditions fared when experts recently rated them on benefit using a scoring system recommended by a task force of the American College of Medical Genetics. Finally, we analyze how benefit is reflected in the public comments submitted in response to the ACMG report. Results show that benefit has been and remains a core consideration for screening decisions. Historically the focus has been on improved physical health as a result of medical treatment; however, in only 4 of the 78 conditions rated does newborn screening prevent all negative consequences. In fact the majority of both core conditions (51.7%) and secondary targets (87.5%) recommended in the ACMG report were rated as having treatments that prevented only some negative consequences. All conditions rated had perceived benefits for family and society, but currently no conditions are screened on the basis of family or societal benefits alone. No agreed-upon threshold exists for what would be considered meaningful benefit, and stakeholder groups differ in their perceptions of benefit. We conclude by suggesting several key research studies needed to further inform public policy.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183568
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The aim of newborn screening is to identify presymptomatic healthy infants that will develop significant metabolic or endocrine derangements if left undiagnosed and untreated. The goal of ultimately reducing or eliminati...The aim of newborn screening is to identify presymptomatic healthy infants that will develop significant metabolic or endocrine derangements if left undiagnosed and untreated. The goal of ultimately reducing or eliminating irreversible sequelae is reached by maximizing test sensitivity of the primary newborn screening that measures specific analytes by a number of methodologies. Differentiation of true from false negatives is accomplished by the test specificity. This review discusses disorders for which, in general, there are available therapies and that are detected by routine and expanded newborn screening. Recommendations are presented for evaluation by a primary care physician, with confirmation by a metabolic or endocrinology specialist. Disorders are organized in tabular format by class of pathway or analyte, with attention to typical clinical presentations, confirmatory biochemical and molecular tests, and therapies. There are numerous challenges in clinical follow-up, including diagnosis and appropriate understanding of the consequences of the disorders. The data required to meet these challenges can be acquired only by large scale longitudinal comprehensive studies of outcome in children identified by newborn screening. Only with such data can newborn screening fully serve families.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17183567
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Newborn screening has existed as a state-based public health service since the early 1960s. Every state and most territorial jurisdictions have comprehensive newborn screening programs in place, but in the United States...Newborn screening has existed as a state-based public health service since the early 1960s. Every state and most territorial jurisdictions have comprehensive newborn screening programs in place, but in the United States a national newborn screening policy does not exist. This results in different administrative infrastructures, screening requirements, laboratory and follow-up services, medical management approaches, and related activities across the country. Federal initiatives and support have contributed to limited evaluations of various aspects of individual newborn screening programs at the national level, but funding is an issue. The national evaluation strategies have taken various forms, all with the intent of improving the screening system through review of actions taken and suggestions for future improvements. While participation in the national evaluation effort for newborn screening laboratory practices includes all US programs, and this has aided in improving quality and harmonizing protocols, other national evaluation activities have been only moderately successful. National data reporting of quality indicators for various program elements must be comprehensive and timely, and the elements must be universally accepted in order to meet the evaluation and improvement needs of the national newborn screening system. A comprehensive real time national evaluation activity will likely require additional resources and enforcement incentives. Limited federal actions through grant incentives and selected reporting requirements provide a possible means of stimulating programs to participate in national harmonization efforts.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17061290
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Cognitive impairment has long been associated with the natural history of HIV among vertically infected children. In children, HIV may have a direct or indirect impact on the developing brain, may lead to global or highl...Cognitive impairment has long been associated with the natural history of HIV among vertically infected children. In children, HIV may have a direct or indirect impact on the developing brain, may lead to global or highly specific consequences, and may be responsible for minor cognitive consequences or, conversely, long-term and severe disability. This differential impact is related to multiple factors that influence the individual expression of the virus in any given child. This review provides an overview of the relevant literature on neurocognitive outcomes for infants, children, and youth vertically infected with HIV, with attention to those factors impacting neurocognitive outcome within a developmental framework. Research findings in both the era preceding and following the introduction of combined therapies are reviewed, since many of the issues identified prior to state-of-the-art treatment currently available in the United States and other developed countries still apply in much of the developing world. Intervention issues and directions for future research are also discussed.
Gerson AC, Butler R, Moxey-Mims M
… +7 more, Wentz A, Shinnar S, Lande MB, Mendley SR, Warady BA, Furth SL, Hooper SR
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17061289
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Given the rise in chronic kidney disease (CKD) in both children and adults, CKD has recently been targeted as a public health priority. Childhood onset kidney disease is generally a noncurable and progressive condition t...Given the rise in chronic kidney disease (CKD) in both children and adults, CKD has recently been targeted as a public health priority. Childhood onset kidney disease is generally a noncurable and progressive condition that leads to kidney failure by early adulthood. Fortunately, improved identification of kidney problems allows for early intervention, which is thought to slow progression toward end-stage renal disease. In addition, medical interventions for pediatric end-stage renal disease have also improved, allowing children to take advantage of lifesaving renal replacement treatments such as dialysis and kidney transplantation. In spite of improvements in identification and treatment, CKD causes both direct and indirect insults to a variety of organ systems. This paper reviews recently published studies pertaining to the neurocognitive and psychosocial impact of CKD on children of various ages and at various stages of kidney failure. Specific attention is focused on summarizing peer reviewed research that describes associations between kidney functioning and cognitive functioning, language acquisition, visual spatial abilities, memory, and executive functioning. In addition, peer reviewed research describing psychosocial outcomes associated with CKD related to academic achievement, social-behavioral functioning, and quality of life are summarized. The authors also identified disease-specific factors that likely mediate neurocognitive outcomes (e.g., anemia, hypertension, cardiovascular) and endorse the importance of continued interdisciplinary research collaborations that will provide a better understanding of the mechanisms responsible for improved neurocognitive functioning after transplantation. The authors conclude this review by describing a multicenter, prospective, longitudinal, National Institutes of Health funded study that is currently examining the developmental outcomes of children with mild to moderate CKD. The authors speculate that the Chronic Kidney Disease in Children Prospective Cohort Study (CKiD) findings will provide additional evidence-based guidance for clinicians and researchers working with children and adolescents with deteriorating kidney function to improve medical and developmental outcomes.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17061288
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The most devastating complication of sickle cell anemia is cerebral infarction, affecting approximately 30% of all individuals with sickle cell anemia. Despite being one of the most common causes of stroke in infants and...The most devastating complication of sickle cell anemia is cerebral infarction, affecting approximately 30% of all individuals with sickle cell anemia. Despite being one of the most common causes of stroke in infants and children, the mechanism of cerebral infarction in this population has not been extensively studied and is poorly understood. Multiple, synergistic factors are important in the pathogenesis of stroke including the hemodynamic effects of cerebral arterial occlusive disease, viscosity, chronic and acute anemia and acute medical events. This review focuses on the relationship between these factors in order to provide a foundation for further study of the etiology of strokes in this high-risk population.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17061287
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We review research on the neuropsychological effects that central nervous system (CNS) cancer treatments have on the cognitive abilities of children and adolescents. The authors focus on the two most common malignancies...We review research on the neuropsychological effects that central nervous system (CNS) cancer treatments have on the cognitive abilities of children and adolescents. The authors focus on the two most common malignancies of childhood: leukemias and brain tumors. The literature review is structured so as to separate out earlier studies, generally those published prior to 1995, as opposed to manuscripts that have been published within the past decade. This is an important distinction for both leukemia and brain tumors. Earlier studies were ground breaking in that they began to map out what could be expected in terms of intelligence and academic problems in survivors of pediatric malignancies. Survivorship in this population has and continues to markedly increase and this is largely due to changes in treatment protocols. Research on neurocognitive effects of disease and treatment in pediatric oncology has become increasingly sophisticated, and this literature review not only reflects this trend, but highlights the growing collaboration between neuropsychology, cognitive neuroscience, and neuro-imaging. Thus, our goal was to provide a historical foundation, lead the reader towards the progression of research methodology up to the current state of the art, and perhaps most importantly, discuss future directions. These directions are especially relevant to the concepts of remediation and treatment of cognitive problems, and this is emphasized at the conclusion of the review.
Ment Retard Dev Disabil Res Rev
· 2006 · PMID 17061286
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Successful treatment of many childhood diseases once considered terminal has resulted in the emergence of long-term effects of the disease or consequences of treatment that were previously unrecognized. Many of these lon...Successful treatment of many childhood diseases once considered terminal has resulted in the emergence of long-term effects of the disease or consequences of treatment that were previously unrecognized. Many of these long-term effects involve the central nervous system (CNS) and are developmental in the way that they emerge over time. Because we are now able to observe the natural history of childhood diseases such as sickle cell anemia or HIV, or the consequences of treatment of disease such as leukemia, brain tumors, or kidney disease, we are also able to study a number of biological mechanisms that result in long-term neurocognitive impairment. While some of the neurodevelopmental outcomes can be directly linked to structural damage of the CNS, other systems (e.g., hematologic, immunologic, pulmonary) appear to play crucial indirect roles in the development of the CNS and neurocognitive abilities because of the way that they affect the course of brain development and activity of the brain across time. Important interactions between acute disease factors, biological mechanisms, age at the time of disease or treatment effect, and disruptions in patterns of development after successful treatment or management all provide support for a neurodevelopmental model of childhood chronic illness. Testing this model may make it possible to more accurately predict the timing and degree of severity of long-term neurodevelopmental consequences, provide guidance for improved treatment and prevention, and offer better understanding of neurodevelopmental disruptions that occur in other non-chronic illness related disabilities.