Cytological and epidemiological findings in trisomies 13, 18, and 21: England and Wales 2004-2009.

This study describes the cytological and epidemiological findings in 985 trisomy 13 and 2512 trisomy 18 compared with 10,255 trisomy 21 diagnoses between 2004 and 2009 included in the National Down Syndrome Cytogenetic Register of England and Wales. The frequency of occurrence, proportions diagnosed prenatally, sex ratios, mean maternal age, and proportions of mothers with recurrences were analyzed. Ninety-seven, 98%, and 92% were free karyotypes for trisomy 21, 18, and 13, respectively; 3% of 21, 1% of 18, and 8% of trisomy 13 were translocations; and under 1% of trisomies 21 and 18 were double or triple aneuploids.

Cytogenetic and epidemiological findings in Down syndrome: England and Wales 1989-2009.

This study describes the characteristics of karyotypes leading to phenotypic Down syndrome (trisomy 21) in 29,256 cases diagnosed between 1989 and 2009 in England and Wales included in the National Down Syndrome Cytogenetic Register (NDSCR). The frequency of occurrence of the different karyotypes, proportions diagnosed prenatally, sex ratios, mean maternal age, and proportions of mothers with recurrences were analyzed. Nearly 97% of all cases were free trisomy 21; 2.

The proportions of Down's syndrome pregnancies detected prenatally in England and Wales from 1989 to 2004.

Objectives: The proportion of Down's syndrome pregnancies detected prenatally in England and Wales is lower in younger mothers than in older mothers. This paper examines the reasons for this apparent age inequality.

Methods: We used data from the National Down Syndrome Cytogenetic Register (NDSCR) to examine the time trend of the proportion of Down's syndrome pregnancies diagnosed prenatally according to maternal age over the years 1989-2004 in England and Wales.

Maternal age-specific fetal loss rates in Down syndrome pregnancies.

Objectives: Pregnancies affected by Down syndrome (DS) have a greater risk of spontaneous fetal loss than those that are unaffected. In this article, we investigate the relationship between maternal age and the risk of spontaneous fetal loss in DS pregnancies.

Methods: Fetal loss at different maternal ages were estimated by survival analysis using follow-up of 5177 prenatally diagnosed cases.

Recurrences of free trisomy 21: analysis of data from the National Down Syndrome Cytogenetic Register.

Objectives: To determine the recurrence risk of a free trisomy 21 pregnancy.

Methods: Data from the National Down Syndrome Cytogenetic Register (NDSCR), which contains information on nearly all cases of Down syndrome between 1989 and 2001 in England and Wales were used. Among 11 281 women with a Down syndrome pregnancy who had had at least one previous pregnancy there were 95 women who had had a previous Down syndrome pregnancy.

Risk of a Down syndrome live birth in women 45 years of age and older.

Objectives: To determine the risk of a Down syndrome (DS) live birth for women 45 years of age and over.

Methods: A meta-analysis of data from five published articles, 13 EUROCAT congenital anomaly population registers and two unpublished sources.

Results: Information was available on the number of DS live births occurring amongst 13,745 live births to women 45 years of age and over.

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.

Prenatal screening for Down syndrome in England and Wales and population-based birth outcomes.

Objective: Whether the introduction of antenatal screening for Down syndrome in England and Wales with serum biochemistry or ultrasound has led to improvements in patient outcomes is unknown. The purpose of this study was to relate pregnancy outcomes to the dominant method used for prenatal Down syndrome screening.

Study Design: For the years 1989 through 1999, England and Wales were divided into geographically defined areas where specific hospitals, health authorities, and cytogenetic laboratories provided maternity care for well-defined populations.

Comparison of models of maternal age-specific risk for Down syndrome live births.

Objectives: To display and compare the different published formulae that specify the association between maternal age and the risk of a Down syndrome live birth.

Methods: Papers published since 1987 on the prevalence of Down syndrome live births in relation to maternal age were located using MEDLINE and the references given in other papers. The data series and the models fitted to them were plotted to obtain a visual idea of their similarities and differences.

Revised estimates of the maternal age specific live birth prevalence of Down's syndrome.

Objectives: To revise the estimates of maternal age specific live birth prevalence of Down's syndrome in the absence of antenatal screening and selective termination using newly available data.

Setting And Design: Data were used from the National Down Syndrome Cytogenetic Register (NDSCR), which contains information on nearly all antenatally or postnatally diagnosed cases of Down's syndrome in which a karyotype was confirmed between 1989 and 1998 in England and Wales. It is the largest single series of data on the prevalence of Down's syndrome.

Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury.

Study Design: A paired comparison of the peak and submaximal responses of oxygen uptake and heart rate in patients with spinal cord injury (SCI) performing voluntary arm cycle exercise and functional electrical stimulation (FES) leg cycling exercise.

Objectives: To test if the blunted heart rate response and slower rate of adjustment of oxygen uptake seen in patients with SCI performing FES leg cycle exercise are also characteristic of arm exercise in these patients.

Methods: Eight paraplegics performed incremental and constant work rate (CWR) exercise with the legs and arms.

Female predominance (low sex ratio) in 47,+21 mosaics.

Data from the New York State Chromosome Registry on over 10,000 cases of Down syndrome reported from 1977 to 1996 confirm findings in the England and Wales Cytogenetic Register that in mosaic 46/47,+21 cases of Down syndrome the male/female ratio (as inferred from XY and XY karyotypes respectively) is less than 1.0 as opposed to the ratio in nonmosaic 47,+21 cases in which the ratio is close to 1.2, or in the general background population with ratio of about 1.

Is there evidence of clustering in Down syndrome?

Background: Associations between environmental hazards and the occurrence of congenital anomalies may be detectable by seeking evidence of non-random occurrence of cases (clusters). There have been a number of anecdotal reports of occurrences of clusters of Down syndrome (DS).

Methods: Data from a national register of cytogenetic diagnoses of Down syndrome births and legal terminations occurring between 1989 and 1995 were used to examine the possibility of clustering.

Physiologic responses during functional electrical stimulation leg cycling and hybrid exercise in spinal cord injured subjects.

Objectives: (1) To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects.

Design: Nonrandomized control trial whereby subjects act as their own control.

Setting: Outpatient rehabilitation in a primary care hospital.

Reliability of statistics on Down's syndrome notifications.

Objectives: To evaluate the completeness of notifications of Down's syndrome live births and terminations to the Office for National Statistics (ONS) using data from the National Down Syndrome Cytogenetic Register (NDSCR). To examine the agreement of observed birth prevalence of Down's syndrome with the expected birth prevalence derived from published maternal age specific rates.

Methods: The number of live births (adjusted to allow for the estimated underascertainment) and the number of terminations due to fetal Down's syndrome from NDSCR were compared with those figures reported to the ONS.

Changes in gas exchange kinetics with training in patients with spinal cord injury.

We examined the ability of patients with spinal cord injury to undergo adaptations to chronic exercise training (cycle ergometry) invoked by functional electrical stimulation (FES) of the legs. Nine such patients performed incremental and constant work rate exercise before and after exercise training. Exercise sessions averaged 2.

Cytogenetic and epidemiological findings in Down syndrome, England and Wales 1989 to 1993. National Down Syndrome Cytogenetic Register and the Association of Clinical Cytogeneticists.

Data from the National Down Syndrome Cytogenetic Register is used to describe the cytogenetics and epidemiology of registered cases. The register comprises notifications from cytogenetics laboratories in England and Wales. This report is of 5737 cases registered between 1989 and 1993: 2169 prenatal and 3436 postnatal diagnoses, and 132 spontaneous abortions.

Peak and submaximal physiologic responses following electrical stimulation leg cycle ergometer training.

Eight males with spinal cord injury (SCI) participated in an exercise training program using neuromuscular electrical stimulation (NMES) leg cycle ergometry. Each subject completed a minimum of 24 (mean +/- SD = 38.1 +/- 17.

The natural history of Down syndrome conceptuses diagnosed prenatally that are not electively terminated.

The pregnancy outcomes on cases of Down syndrome diagnosed prenatally in which the mother did not elect termination were evaluated in data reported to a comprehensive Register of Down syndrome for England and Wales for 1989-94. In the 168 cases in which placental biopsy was not used, the overall rate of spontaneous loss was 35%, but this figure masks considerable heterogeneity by gestational stage at ascertainment. Data on ages at diagnostic procedure and on pregnancy termination enabled a more precise survival analysis.

Gas exchange kinetics during functional electrical stimulation in subjects with spinal cord injury.

We examined the kinetics of VO2, VCO2, and VE following the onset of unloaded leg cycling, and in recovery, in six patients with spinal cord injury (SCI). Exercise was produced by functional electrical stimulation (FES) of the quadriceps, hamstrings, and gluteal muscles. End-exercise VO2 (1.

Down's syndrome births and pregnancy terminations in 1989 to 1993: preliminary findings.

Objective: To investigate changes in the numbers of Down's syndrome births and terminations of pregnancies from 1989 to 1993.

Design: Data from a national register of cytogenetic diagnoses of karyotypes associated with Down's syndrome were analysed to obtain observed numbers of births and terminations of pregnancies known to be affected. Allowance was made for those cases diagnosed prenatally for whom the eventual outcome of the pregnancies had not yet been ascertained.