Current estimate of Down Syndrome population prevalence in the United States.

OBJECTIVE: To calculate a reliable estimate of the population prevalence of Down syndrome in the US. STUDY DESIGN: The annual number of births of infants with Down syndrome were estimated by applying published birth prevalence rates of Down syndrome by maternal age to US data from the Centers for Disease Control and Prevention for the years for which births by maternal age were available (1940-2008). Death certificate data for persons with Down syndrome were available for the years 1968-2007. We estimated the number of people with Down syndrome on January 1, 2008, using a life table approach based on proportions of deaths by age. Monte Carlo sampling was used to create 90% uncertainty intervals (UIs) for our estimates. RESULTS: We estimated the January 1, 2008, population prevalence of Down syndrome as approximately 250700 (90% UI, 185900-321700) based on proportions of deaths by age from the most recent 2 years (2006-2007) of death certificate data. This estimate corresponds to a prevalence of 8.27 people with Down syndrome per 10000 population (90% UI, 6.14-10.62). CONCLUSION: Our estimate of Down syndrome prevalence is roughly 25%-40% lower than estimates based solely on current birth prevalence. The results presented here can be considered a starting point for facilitating policy and services planning for persons with Down syndrome.

Down syndrome and personalized medicine: changing paradigms from genotype to phenotype to treatment.

Personalized Medicine represents a paradigm shift in the conceptual framework of research and clinical care. This shift argues that Down syndrome is a treatable condition, and therefore we must invest in research to improve outcomes. Individuals with Down syndrome have varying levels of increased risk for a number of co-morbidities, including infantile spasms and early onset Alzheimer's disease. We will review research in these associated conditions to show how investigators are attempting to identify biomarkers, including genomic, epigenomic, proteomic and metabolomic "signatures" that will predict who may be at risk to develop a specific co-morbidity prior to onset and will provide novel targets for therapeutic development. This Personalized Medicine approach will permit predictive and preventive approaches for individuals at increased risk for co-morbidities. The support for clinical trials among individuals with Down syndrome is beginning to overcome the "culture of intractability" that has surrounded this disorder.

Call for change in prenatal counseling for Down syndrome.

The American Journal of Medical Genetics Part A is to be congratulated for taking a leadership role by publishing a number of papers challenging the status quo of prenatal counseling for Down syndrome and of care for children and adults with Down syndrome. Parents want to know about the future abilities and potential of their fetus with Down syndrome, not simply negative medical information that may be outdated. Those providing counseling and those providing medical care could benefit from contact with individuals with Down syndrome outside the medical context. It is imperative that each person with Down syndrome be viewed as a unique individual with particular talents. Medical care providers should work with parents to help the child or adult with Down syndrome reach his/her goals.

Síndrome de Down: coacción y eugenesia / No disponible

Los expertos coinciden en que la coacción por parte de las compañías de seguros o de las autoridades gubernamentales para limitar la libre elección reproductiva constituye una práctica eugenésica. Analizamos la discriminación que se realiza contra las familias de niños con síndrome de Down que eligieron no realizar una prueba prenatal o decidieron continuar su embarazo tras el diagnóstico prenatal. Proponemos que esta discriminación representa una coacción económica y social que limita la libertad reproductiva, y mostramos ejemplos de la retórica y política gubernamental que absuelven la eugenesia y de políticas comerciales que cumplen los criterios de eugenesia establecidos por los expertos. Nuestro propósito es el de sensibilizar sobre estos temas al mundo relacionado con la genética clínica, mostrando cómo ofrecer el consejo genético en los términos más neutros y no directivos posibles, y cómo ofrecer atención y asesoramiento postnatales a los niños con síndrome de Down y sus familias. Nos preocupa que si las políticas y las prácticas eugenésicas dirigidas contra las personas con síndrome de Down y sus familias se ven toleradas por los profesionales implicados en el diagnóstico genético y por la sociedad en general, aumentará la probabilidad de que se amplíe la eugenesia dirigida contra otros individuos y comunidades

No disponible

Down syndrome: national conference on patient registries, research databases, and biobanks.

A December 2010 meeting, "Down Syndrome: National Conference on Patient Registries, Research Databases, and Biobanks," was jointly sponsored by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) at the National Institutes of Health (NIH) in Bethesda, MD, and the Global Down Syndrome Foundation (GDSF)/Linda Crnic Institute for Down Syndrome based in Denver, CO. Approximately 70 attendees and organizers from various advocacy groups, federal agencies (Centers for Disease Control and Prevention, and various NIH Institutes, Centers, and Offices), members of industry, clinicians, and researchers from various academic institutions were greeted by Drs. Yvonne Maddox, Deputy Director of NICHD, and Edward McCabe, Executive Director of the Linda Crnic Institute for Down Syndrome. They charged the participants to focus on the separate issues of contact registries, research databases, and biobanks through both podium presentations and breakout session discussions. Among the breakout groups for each of the major sessions, participants were asked to generate responses to questions posed by the organizers concerning these three research resources as they related to Down syndrome and then to report back to the group at large with a summary of their discussions. This report represents a synthesis of the discussions and suggested approaches formulated by the group as a whole.

Personalized medicine for individuals with Down syndrome.

As the cost of whole genome analysis decreases, we have the opportunity to explore the interactions of various gene changes in an individual that lead to their particular phenotype. This will provide the ability to move from the epidemiologic study of groups, in which, the individuals are treated collectively and homogenously, to personalized medicine, and a model in which the individual is recognized and treated as a distinct entity. We will be applying personalized medicine to individuals with Down syndrome in order to understand and develop biomarkers for increased risk of co-morbidities. Personalized medicine will change the "culture of intractability" of Down syndrome.

Down syndrome: coercion and eugenics.

Experts agree that coercion by insurance companies or governmental authorities to limit reproductive choice constitutes a eugenic practice. We discuss discrimination against families of children with Down syndrome who chose not to have prenatal testing or chose to continue a pregnancy after a prenatal diagnosis. We argue that this discrimination represents economic and social coercion to limit reproductive choice, and we present examples of governmental rhetoric and policies condoning eugenics and commercial policies meeting criteria established by experts for eugenics. Our purpose is to sensitize the clinical genetics community to these issues as we attempt to provide the most neutral nondirective prenatal genetic counseling we can, and as we provide postnatal care and counseling to children with Down syndrome and their families. We are concerned that if eugenic policies and practices targeting individuals with Down syndrome and their families are tolerated by clinical geneticists and the broader citizenry, then we increase the probability of eugenics directed toward other individuals and communities.

Down syndrome: issues to consider in a national registry, research database and biobank.

As the quality of life for individuals with Down syndrome continues to improve due to anticipatory healthcare, early intervention, mainstreaming in schools, and increased expectations, the lack of basic information regarding individuals with Down syndrome is being recognized, and the need to facilitate research through a national registry, research database and biobank is being discussed. We believe that there should not be ownership of the samples and information, but instead prefer stewardship of the samples and information to benefit the participants who provided them. We endorse a model with data and sample managers and a research review board to interface between the investigators and participants. Information and samples would be coded, and only a few data managers would know the relationship between the codes and identifying information. Research results once published should be included in an online newsletter. If appropriate, individual results should be shared with participants. A Down syndrome registry, research database and biobank should be accountable to participants, families, medical care providers, government, and funding sources.

Expanded newborn screening: implications for genomic medicine.

Newborn screening (NBS) represents the largest volume of genetic testing. The 45-year history of NBS has demonstrated its benefits, as well as the importance of an evidence base. The recent addition of tandem mass spectrometry (MS/MS) resulted in a fivefold increase in the number of tests. Experience with MS/MS also showed that laboratory tests are just one part of the NBS system. The lessons learned from NBS will provide important insights as we move into the predictive, preventive, and personalized era of genomic medicine.

Molecular genetic confirmatory testing from newborn screening samples for the common African-American, Asian Indian, Southeast Asian, and Chinese beta-thalassemia mutations.

beta-Thalassemia is a serious health problem in the United States, especially in California, due to increased Asian immigration. Neonatal screening by using high-performance liquid chromatography (HPLC) or isoelectric focusing (IEF) may lead to confusion due to interactions of various hemoglobinopathies with beta-thalassemia. Our purpose was to develop single-tube multiplexed PCR assays using original neonatal screening specimens to identify the mutations responsible for beta-thalassemia in order to expedite diagnostic confirmation. Primers were designed for two to six common ethnic-specific mutations using the amplification refractory mutation system (ARMS). This multiplex ARMS approach was standardized using DNA samples with known mutations for beta-thalassemia in those of Asian (Southeast Asian, Chinese, and Asian Indian) and African-American descent. Specimens from African-American neonates were tested for two mutations (-88 and -29); Asian Indians for five mutations (IVSI-1, IVSI-5, codons (Cd) 41/42, Cd 8/9, and 619-bp deletion); Chinese, Taiwanese, and Southeast Asians for seven mutations (Cd 41/42, Cd 17, -28, IVSII-654, Cd 71/72, IVSI-5, and IVSI-1). We identified each of these beta-thalassemia mutations in multiplexed ARMS from positive control samples. We tested 25 anonymized dried blood specimens from neonates who had been diagnosed with beta-thalassemia and who also belonged to these ethnic groups. We detected a mutation specific to the neonate's ethnic group using the ARMS approach in nearly all specimens, and the results were confirmed by sequencing. Multiplexed ARMS for ethnic-specific beta-thalassemia mutations from the original newborn screening dried blood specimens is a rapid and efficient approach for diagnostic confirmation.

Genetic screening: carriers and affected individuals.

Genetic screening utilizes analytical approaches adapted for high throughput to identify carrier and affected individuals in a targeted population. Currently, genetic screening focuses on carrier screening, prenatal screening, and newborn screening. Newborn screening should serve as a model for all genetic screening, with more than forty years of experience and numerous lessons learned. As with all genetic screening, there are policy concerns in newborn screening regarding which disorders and technologies should be selected, and how centralized or decentralized the process to set policy should be. The need to share experiences and develop databases transcends all other policy considerations in genetic screening. The future will see population-based screening for adult-onset disorders. However, there needs to be extensive research to define predictive risk for various ethnocultural groups and to determine effective interventions. Ethical concerns regarding the timing of population screening, as well as the scope of use of information, will need to be resolved if genomic medicine will achieve its promise of a predictive, preventive, and personalized medicine.

IL1RAPL1 is associated with mental retardation in patients with complex glycerol kinase deficiency who have deletions extending telomeric of DAX1.

IL1RAPL1 (interleukin-1 receptor accessory protein-like, gene 1) has recently been shown to be mutated in patients with X-linked mental retardation. Clinical experience has suggested that patients with the contiguous gene syndrome, complex glycerol kinase deficiency (cGKD), will have mental retardation (MR) if they have deletions extending from the GK gene into the DMD gene and/or involving a significant extension telomeric from DAX1. We examined cell lines from patients with cGKD whose clinical features would be informative and would allow us to determine if IL1RAPL1 deletions can help to explain the MR in patients with deletions extending telomeric from DAX1. Our results showed that nearly all patients with deletions involving DAX1, but not DMD, had MR if IL1RAPL1 was deleted. If ILIRAPLI and DMD were intact, the patients with DAX1 deletions only rarely had normal development. Deletions in DNA from patients with cGKD who exhibited MR and had normal IL1RAPL1 all involved the GK and DMD genes. Our data are consistent with the association of IL1RAPL1 gene deletion and MR in the majority of patients with cGKD and deletions extending telomeric from DAX1.

DNA diagnosis confirms hemoglobin deletion in newborn screen follow-up.

Molecular genetic confirmatory testing with polymerase chain reaction amplification is integral to neonatal hemoglobinopathy screening programs. In this study, we demonstrate applicability of polymerase chain reaction-based testing for the common deletions in blacks responsible for hereditary persistence of fetal hemoglobin. This approach will provide rapid diagnostic clarification in newborn screening follow-up.

Newborn screening: rationale for a comprehensive, fully integrated public health system.

Newborn screening has existed for approximately four decades. During that period of time, newborn screening has evolved conceptually from a laboratory test for a single disorder, phenylketonuria (PKU), to a multi-part public health system involving education, screening, diagnostic follow-up, treatment/management, and system evaluation. At a time when newborn screening is recognized as a model for predictive medicine, it also faces critical challenges that will determine its future credibility and viability. In order to understand these challenges, it is helpful to review briefly the history of newborn screening.

Rapid confirmation of Southeast Asian and Filipino alpha-thalassemia genotypes from newborn screening specimens.

Alpha(+)-thalassemia (-alpha) is prevalent throughout tropical and subtropical regions of world, whereas alpha(0)-thalassemia (--) occurs at higher frequency in Southeast Asia. Homozygosity for the alpha(0)-thalassemia deletion (--/--) is a serious health problem in Southeast Asia and the Philippines and is responsible for the majority of hydrops fetalis in this region. Asian immigration in United States has impacted the demography of genetic disease in U.S. As Asians comprise of 10% of all California births and represent a population at highest risk for alpha(0)-thalassemia, we developed a rapid and efficient PCR approach to detect the common alpha(0)-thalassemia deletions in Southeast Asians and Filipinos using newborn screening specimen.