Epidemiology of Down syndrome (Trisomy 21), Hawaii, 1986-97

Adults with Trisomy 21 Have Differential Antibody Responses to Influenza A

Down syndrome is caused by an extra copy of chromosome 21. In the past two decades, the life expectancy of individuals with Down syndrome has significantly increased from early 20s to early 60s, creating a population of individuals of which little is known about how well they are protected against infectious disease. The goal of this work is to better understand if adults with Down syndrome are well protected against influenza following vaccination. We obtained plasma samples from 18 adults (average age = 31yo) with Down syndrome and 17 age/gender-matched disomic individuals, all vaccinated against influenza. Antibody concentration to influenza A was measured using ELISA and antibody titers were measured using a hemagglutinin inhibition assay. Statistical analysis was performed using Stata Statistical Software. Adults with Down syndrome had a significantly increased concentration of antibodies to a mixture of influenza A viral proteins; however, they had a significantly decreased titer to the Influenza A/Hong Kong compared to disomic controls. These findings suggest that more vigorous studies of B- and T-cell function in adults with Down syndrome with respect to influenza vaccination are warranted, and that this population may benefit from a high-dose influenza vaccine.

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.

Association of interleukin-1 polymorphisms with periodontitis in Down syndrome

This study examined the association of IL1 genetic polymorphisms (IL-1A +4845, IL-1B +3954 & IL-1RN +2018) with periodontal disease status of Down syndrome (DS) individuals. Fifty-four DS patients (18-56 yr, 48.15% male, 77.78% Caucasians) were recruited from the Georgia Regional Hospital (GRH) health care system. Two comparable groups (71 mentally retarded patients and 87 control subjects) were also recruited. All subjects were nonsmokers. Periodontal evaluations (plaque index, gingival index, bleeding-on probing and clinical attachment levels (AL)), personal and professional dental care habits were recorded. Blood was collected by a venipuncture. The IL-1A +4845, IL-1B +3954 & IL-1RN +2018 loci were genotyped by the TaqMan assay. No statistically significant differences were noted in the distribution of IL-1 gene polymorphisms between the three groups. The IL-1 variant genotypes varied by race; for both IL-1A and IL-1RN, the variant gene was significantly more prevalent among whites than non-whites (ps > 0.1). ANCOVA, which also adjusted for age, showed a 3-way interaction among dental visits, gene variation and Down status [(F(1, 179) = 3.96, P = 0.048 in White subjects and F(1, 241) = 2.96, P = 0.087 in all subjects). Post-hoc t-tests confirmed lower levels of AL in IL-1RN-variant Down subjects receiving more frequent dental visits (P < 0.05). ANCOVA, which also adjusted for age, showed an interaction between IL-1A/B gene variation and Down status (F(1, 174) = 3.04, P = 0.083 in White subjects and F(1, 235) = 3.72, P = 0.055 in all subjects). Post-hoc t-tests confirmed lower levels of AL in IL-1A/B-variant Down subjects (P < 0.05). The distribution of variant IL-1 genes in DS subjects was not different from the general population. However the association between the carriage of the IL-1 rare alleles and periodontitis differed between the Down and non-Down subjects. The carriage of the IL-1 rare alleles in the Down subjects tended to confer a protective effect against loss of periodontal attachment.

Health inequity in children and youth with chronic health conditions

BACKGROUND

Over the last decades, there have been great advances in health care delivered to children with chronic conditions, but not all children have benefitted equally from them.

OBJECTIVES

To describe health inequities experienced by children with chronic health conditions.

METHODS

We performed a literature review of English-language studies identified from the Medline, Centers for Disease Control and Prevention, National Cancer Institute, and Cystic Fibrosis Foundation Web sites that were published between January 1985 and May 2009, included children aged 0 to 18 years, and contained the key words "incidence," "prevalence," "survival," "mortality," or "disparity" in the title or abstract for the following health conditions: acute leukemia, asthma, attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorders, cerebral palsy, cystic fibrosis, diabetes mellitus, Down syndrome, HIV/AIDS, major congenital heart defects, major depressive disorder, sickle cell anemia, spina bifida, and traumatic brain injury.

RESULTS

Black children had higher rates of cerebral palsy and HIV/AIDS, were less likely to be diagnosed with ADHD, had more emergency department visits, hospitalizations, and had higher mortality rates associated with asthma; and survived less often with Down syndrome, type 1 diabetes, and traumatic brain injury when compared with white children. Hispanic children had higher rates of spina bifida from Mexico-born mothers, had higher rates of HIV/AIDS and depression, were less likely to be diagnosed with ADHD, had poorer glycemic control with type 1 diabetes, and survived less often with acute leukemia compared with white children.

CONCLUSIONS

Serious racial and ethnic health and health care inequities persist for children with chronic health conditions.

Survival of Texas infants born with trisomies 21, 18, and 13

Trisomies 21, 18, and 13 are the three most common trisomies among infants who survive to 20 weeks gestation or more. Overall information about birth prevalence, natural history, and mortality for all three trisomies is well defined, but information about ethnic-specific rates is limited. Only a few studies have examined mortality rates of trisomies 18 and 13 because so few cases are liveborn and most have very short life spans. This study assessed ethnic-specific population-based survival probabilities among infants for each trisomy. All cases of trisomies 21, 18, and 13 born in Texas between 1999 and 2003 were obtained from the Texas Birth Defects Registry and included 2,260 cases of trisomy 21, 398 cases of trisomy 18, and 213 cases of trisomy 13. Date and cause of death were obtained from the Texas vital statistics records and the National Death Index. Overall, birth prevalence rates (per 10,000 adjusted live births) for the three trisomies were 11.74 (95% CI: 11.25-12.25), 1.34 (95% CI: 1.18-1.52), 0.92 (95% CI: 0.79-1.07), respectively, and are consistent with previously reported rates. There were no differences in survival rates by ethnicity and the median survival for each trisomy was consistent with previous reports. The results of this study provide comprehensive population-based information for survival of infants with trisomies 21, 18, and 13.

Epidemiology of congenital anomalies in a population-based birth registry in Taiwan, 2002

BACKGROUND/PURPOSE

Congenital anomalies are important medical and public health conditions. However, the occurrence rates of congenital anomalies and their risk factors are unknown in Taiwan. We used the medical-practitioner-reported birth registry in 2002 to determine the occurrence of individual congenital anomalies and their associated risk factors, such as maternal age, fetal sex, and plurality.

METHODS

The birth registry was started in 2001 in Taiwan. We obtained the data for 2002 from the Department of Health, and translated the coding of congenital anomalies to International Classification of Diseases 9th revision-clinical modification (ICD-9-CM). The occurrence rates of individual congenital anomalies were calculated. The effects of maternal age, fetal sex, and plurality were calculated as odds ratios (ORs) by logistic regression analysis.

RESULTS

A total of 1775 infants were diagnosed as having congenital anomalies among 242,140 live and deceased newborn infants delivered in Taiwan in 2002.The occurrence rates of congenital anomalies of the nervous system, eyes and face, cardiovascular, digestive, urogenital, musculoskeletal and respiratory systems, and chromosomes were 0.67 per thousand, 1.86 per thousand, 1.47 per thousand, 0.62 per thousand, 0.71 per thousand, 2.05 per thousand, 0.07 per thousand and 0.79 per thousand, respectively. Sex chromosomal anomalies, Down syndrome, and trisomy 18 were associated with maternal age of > or = 35 years (OR, 15.9, 4.6, and 2.3, respectively). Such elevation was even more prominent for maternal age > or = 40 years (OR, 35.5, 22.2, and 11.62, respectively). A milder and borderline significant maternal age (> or = 40 years) effect was seen with cleft lip, with or without cleft palate (OR, 2.1). Female births had more cleft palates (OR, 1.6). There was no relationship between plurality and anomalies.

CONCLUSION

The occurrence rates for individual congenital anomalies in Taiwan were reported. Older maternal age was a risk factor for the occurrence of chromosomal and orofacial anomalies. More active prenatal screening and further investigation of causal factors of congenital anomalies are of major importance.

Hospitalizations of infants and young children with Down syndrome: evidence from inpatient person-records from a statewide administrative database

BACKGROUND

Although individuals with Down syndrome are increasingly living into the adult years, infants and young children with the syndrome continue to be at increased risk for health problems. Using linked, statewide administrative hospital discharge records of all infants with Down syndrome born over a 3-year period, this study 'follows forward' over 200 infants with Down syndrome from each individual's birth until they turn 3 years of age. By utilizing this procedure, we were able to assess the amount, reasons for, and timing of inpatient hospitalization and to investigate how congenital heart defects (CHDs) relate to hospitalization for young children with Down syndrome.

METHOD

This population-based, retrospective study used statewide administrative hospital discharge data. Subject inclusion criteria included residents of Tennessee, born between 1997 and 1999, and diagnosed with Down syndrome at birth. Inpatient records were linked to create person-record histories of hospitalization from birth to age 3. Main outcomes included the number of Non-birth Hospitalizations, length of stay, principal and other diagnosis codes to indicate reason(s) for hospitalization, and patient's age at first (non-birth) hospitalization. Procedure codes were added to determine if children with CHD were hospitalized primarily for operations on the heart.

RESULTS

Of 217 births, 213 children survived birth; 54% (115) had CHDs. Almost half (49.8%) of all children were hospitalized before age 3; these 106 children were admitted 245 times. Children with CHDs were 2.31 times more likely to be hospitalized than children without CHDs. Respiratory illnesses affected 64.9% of all hospitalized children with CHD, were the principal diagnoses in 38.3% of their hospitalizations, and were the main principal diagnoses for non-CHD children. Thirty-three (of 77) hospitalized children with CHD underwent cardiac surgeries, accounting for 19.3% of all admissions. Median time to first hospitalization was 96 days (CI: 78-114) for CHD infants, 197 days (CI: 46-347) for non-CHD infants.

CONCLUSIONS

Children with Down syndrome are at high risk for early hospitalization. Prevention and treatment of respiratory illnesses require more attention. Down syndrome is associated with early, serious, physical health problems and substantial inpatient care use.

Influence of advanced age of maternal grandmothers on Down syndrome

BACKGROUND

Down syndrome (DS) is the most common chromosomal anomaly associated with mental retardation. This is due to the occurrence of free trisomy 21 (92-95%), mosaic trisomy 21 (2-4%) and translocation (3-4%). Advanced maternal age is a well documented risk factor for maternal meiotic nondisjunction. In India three children with DS are born every hour and more DS children are given birth to by young age mothers than by advanced age mothers. Therefore, detailed analysis of the families with DS is needed to find out other possible causative factors for nondisjunction.

METHODS

We investigated 69 families of cytogenetically confirmed DS children and constructed pedigrees of these families. We also studied 200 randomly selected families belonging to different religions as controls. Statistical analysis was carried out using logistic regression.

RESULTS

Out of the 69 DS cases studied, 67 were free trisomy 21, two cases were mosaic trisomy 21 and there were none with translocation. The number of DS births was greater for the young age mothers compared with the advanced age mothers. It has also been recorded that young age mothers (18 to 29 years) born to their mothers at the age 30 years and above produced as high as 91.3% of children with DS. The logistic regression of case- control study of DS children revealed that the odds ratio of age of grandmother was significant when all the four variables were used once at a time. However, the effect of age of mother and father was smaller than the effect of age of maternal grandmother. Therefore, for every year of advancement of age of the maternal grandmother, the risk (odds) of birth of DS baby increases by 30%.

CONCLUSION

Besides the known risk factors, mother's age, father's age, the age of the maternal grandmother at the time of birth of the mother is a risk factor for the occurrence of Down syndrome.

The pattern of down syndrome among children in Qatar: A population-based study

BACKGROUND

The objective of the present study was to determine the prevalence pattern of Down Syndrome (DS) in children <5 years of age in the State of Qatar. This is a retrospective descriptive study. The study was conducted in the Hamad General Hospital, Women's Hospital, and Rumailah Hospital (Hamad Medical Corporation). A total of 146 children were reported as having DS during the 6-year period from 1 January 2000 to December 31, 2005.

METHODS

The diagnostic classification of definitive DS was made in accordance with criteria based on the International Classification of Disease 10th Revision (ICD-10). The data collected from the medical records included sociodemographic characteristics of the children, genetic and family history, pedigree analysis, and clinical genetic examination.

RESULTS

A total of 146 children were diagnosed with DS during the last 6-year period and the prevalence rate is 19.5 per 10,000 live births. Of these, 40.4% were Qataris and 59.6% were non-Qataris. DS was slightly more common in boys (52.7%) than girls (47.3%). Infants <1 year old had the highest frequency of DS (40.4%), followed by children (1-2) years (26%). The most common abnormality was regular trisomy (98%). Also, one-half of the studied children had congenital heart problems (51.7%). There is a significant relationship between DS and maternal age as reported by other studies in other countries.

CONCLUSION

The identification of specific types of chromosomal abnormalities in DS children is important as it enables clinicians to accurately counsel the parent regarding the recurrence risk and available options.

Perinatal loss of Ts65Dn Down syndrome mice

Ts65Dn mice inherit a marker chromosome, T(17(16))65Dn, producing segmental trisomy for orthologs of about half of the genes on human chromosome 21. These mice display a number of phenotypes that are directly comparable to those in humans with trisomy 21 and are the most widely used animal model of Down syndrome (DS). However, the husbandry of Ts65Dn mice is complicated. Males are sterile, and only 20-40% of the offspring of Ts65Dn mothers are trisomic at weaning. The lower-than-expected frequency of trisomic offspring has been attributed to losses at meiosis, during gestation and at postnatal stages, but no systematic studies support any of these suppositions. We show that the T(17(16))65Dn marker chromosome is inherited at expected frequency and is fully compatible with development to midgestation. Disproportional loss of trisomic offspring occurs in late gestation and continues through birth to weaning. Different maternal H2 haplotypes are significantly associated with the frequency of trisomy at weaning in patterns different from those reported previously. The proportion of trisomic mice per litter decreases with age of the Ts65Dn mother. These results provide the first statistical and numerical evidence supporting the prenatal and perinatal pattern of loss in the Ts65Dn mouse model of DS.

Epidemiology of double aneuploidies involving chromosome 21 and the sex chromosomes

The chance of two chromosome abnormalities occurring in one conceptus is very small. However, some authors have suggested that double aneuplodies (DAs) might be more common than the product of their individual frequencies. The nonrandomness of such DA events was considered to be evidence that nondisjunction (NDJ) may be genetically determined. Data collected from the National Down syndrome Cytogenetic Register (NDSCR) in England and Wales and from the literature indicate that the frequencies of all nonmosaic DAs, except for 48,XXY,+21, are lower than expected, probably because of strong intrauterine selection against such pregnancies. Collectively, we identified 52 cases of nonmosaic 48,XXY,+21; 28 cases of 48,XYY,+21; and 14 cases of 48,XXX,+21 in liveborns and 13 cases of 48,XXY,+21; four cases of 48,XYY,+21; and two cases of 48,XXX,+21 after prenatal diagnoses. Among these cases, analysis of the published unbiased cytogenetic surveys of liveborn DS revealed 24 cases of 48,XXY,+21; nine cases of 48,XYY,+21; and seven cases of 48,XXX,+21. These figures are different from the expected proportion of 1:1:1 (P < 0.001), with carriers of XXY overrepresented in the group of carriers of DA. Mechanisms put forth to account for the higher occurrence of 48,XXY,+21 may include greater accessibility of disomic ovum to Y-carrying sperm, and promotion of NDJ in ovum by Y-bearing sperm. 48,XXY,+21 DA was found to be age-dependent, as the proportion of mothers over age 35 (x = 33.0) was increased over the general population. This is in contrast to the apparently age-independent 48,XYY,+21 DA, with a mean maternal age of 24.7 (P < 0.001). Paternal ages were also remarkably different between the groups, with a mean age of 37.9 in 48,XXY,+21 cases and a mean age of 27.9 in 48,XYY,+21 cases (P < 0.01). Maternal age-related factors, rather than genetic predisposition, may play a more important role in the etiology of the most common DA, 48,XXY,+21.

Trisomy 21 and congenital heart disease: effect of timing of initial echocardiogram

Current recommendations for infants with trisomy 21 include an echocardiogram in the first month of life. The purposes of this study were to determine whether outcome and presence of transient shunting differed between infants with echocardiograms in the first month (Group I) and those performed later (Group II). Transient patent ductus arteriosus was more commonly seen in Group I. Presence of a patent foramen ovale, failure to return for follow-up, and surgical mortality rate did not differ between the 2 groups. A more selective policy related to timing of the initial echocardiogram in asymptomatic infants with trisomy 21 appears to be warranted.

Prenatal diagnosis, pregnancy terminations and prevalence of Down syndrome in Atlanta

BACKGROUND

The impact of prenatal diagnosis on the live birth prevalence of Down syndrome (trisomy 21) has been described. This study examines the prevalence of Down syndrome before (1990-1993) and after inclusion of prenatally diagnosed cases (1994-1999) in a population-based registry of birth defects in metropolitan Atlanta.

METHODS

We identified infants and spontaneous fetal deaths with Down syndrome (n = 387), and pregnancies electively terminated after a prenatal diagnosis of Down syndrome (n = 139) from 1990 to 1999 among residents of metropolitan Atlanta from a population-based registry of birth defects, the Metropolitan Atlanta Congenital Defects Program (MACDP). Only diagnoses of full trisomy 21 were included. Denominator information on live births was derived from State of Georgia birth certificate data. We compared the prevalence of Down syndrome by calendar period (1990-1993, 1994-1999), maternal age (<35 years, 35+ years), and race/ethnicity (White, Black, other), using chi-square and Fisher's exact tests.

RESULTS

During the period when case ascertainment was based only on hospitals (1990-1993), the prevalence of Down syndrome was 8.4 per 10,000 live births when pregnancy terminations were excluded and 8.8 per 10,000 when terminations were included. When case ascertainment also included perinatal offices (1994-1999), the prevalence of Down syndrome was 10.1 per 10,000 when terminations were excluded and 15.3 when terminations were included. During 1990-1993, the prevalence of Down syndrome was 24.7 per 10,000 among offspring to women 35+ years of age compared to 6.8 per 10,000 among offspring to women <35 years of age (rate ratio [RR] = 3.65, 95% confidence interval [CI] = 2.53-5.28). During 1994-1999, the prevalence of Down syndrome was 55.3 per 10,000 among offspring to women 35+ years compared to 8.5 per 10,000 among offspring to women <35 years (RR = 6.55, 95% CI = 5.36-7.99). There was no statistically significant variation in the prevalence of Down syndrome by race/ethnicity within maternal age and period of birth strata. During 1994-1999, the proportion of cases that were electively terminated was greater for women 35+ years compared to women <35 years (RR = 5.10, 95% CI = 3.14-8.28), and lower for Blacks compared to Whites among women 35+ years of age (RR = 0.33, 95% CI = 0.16-0.66).

CONCLUSIONS

In recent years, perinatal offices have become an important source of cases of Down syndrome for MACDP, contributing at least 34% of cases among pregnancies in women 35+ years of age. Variation in the prevalence of Down syndrome by race/ethnicity, before or after inclusion of cases ascertained from perinatal offices, was not statistically significant. Among Down syndrome pregnancies in mothers 35+ years we found a lower proportion of elective termination among Black women compared to White women. We suggest that future reports on the prevalence of Down syndrome by race/ethnicity take into account possible variations in the frequency of prenatal diagnosis or elective termination by race/ethnicity.

Maternal age-specific Down syndrome rates by maternal race/ethnicity, Hawaii, 1986-2000

BACKGROUND

Published maternal age-specific rates for Down syndrome are based mostly on populations of predominately European origin. Down syndrome rates have been reported to vary by race/ethnicity. The objective of this study was to calculate maternal age-specific Down syndrome rates for various racial/ethnic groups and to compare the rates between the racial/ethnic groups.

METHODS

Data were obtained from a population-based birth defects registry and included all Down syndrome cases delivered in Hawaii during 1986-2000 with maternal race/ethnicity of white, Far East Asian, Pacific Islander, or Filipino. Maternal age-specific Down syndrome rates were calculated for each race/ethnicity, and the rates were compared.

RESULTS

The pattern of maternal age-specific Down syndrome rates among Far East Asians and Filipinos was similar to that among whites--Down syndrome rates increased with maternal age, with the increase in rate being most obvious for maternal age groups of 35 years or greater. However, for maternal age of 35 years or greater, the Down syndrome rate was lower for Pacific Islanders than whites, with the difference between the two racial/ethnic groups being significant for maternal age of 40 years or greater (rate ratio 0.13, 95% confidence interval 0.02-0.48).

CONCLUSIONS

All racial/ethnic groups do not appear to demonstrate the same maternal age pattern of Down syndrome rates as whites. This is important because maternal age-specific Down syndrome rates are used to calculate expected Down syndrome rates in a population and to estimate a woman's risk of having an infant with Down syndrome given her age.

First-year mortality rates for selected birth defects, Hawaii, 1986-1999

Birth defects have been the leading cause of infant death in the United States for over the last decade. However, there is little population-based data on the first-year mortality rates for many specific birth defects and the factors that may affect these mortality rates. This investigation examined the first-year mortality rates for 54 selected birth defects of various organ systems in Hawaii during 1986-1999 using data from a population-based birth defects registry and evaluated the impact of the presence of chromosomal abnormalities and other structural birth defects and the year of delivery on the mortality rates. Mortality rates varied widely by defect, being highest for anencephaly (100%), trisomy 13 (82%), and trisomy 18 (74%), while no first-year deaths were reported for glaucoma, bladder exstrophy, and persistent cloaca. The majority (36 of 54 or 67%) of the birth defects had a mortality rate of less than 25%. Among the 51 structural birth defects, 38 (75%) had higher first-year mortality rate for cases with chromosomal abnormalities and 42 (82%) had higher first-year mortality rates for cases with other major structural birth defects. The mortality rate among 1986-1992 deliveries was higher than the mortality rate among 1993-1999 deliveries for 37 (69%) of the 54 birth defects. This study indicates that first-year mortality rates vary widely by type of birth defect, although the mortality rate for the majority of birth defects is relatively low. The presence of a chromosomal abnormality or other structural birth defect increases the mortality rate, and mortality rates for the majority of birth defects have declined in Hawaii during the study period.