Diagnostic prénatal et prévalence de la trisomie 21 en population parisienne, 2001–2005

Recent trends in the birth prevalence of Down syndrome in China: impact of prenatal diagnosis and subsequent terminations

OBJECTIVE

This study aims to analyze recent trends in Down syndrome (DS) prevalence in China and evaluate the impact of prenatal diagnosis and subsequent terminations.

DESIGN

A birth defects surveillance-based retrospective study was adopted.

METHODS

On the basis of the 1996 to 2011 surveillance data for DS from Chinese Birth Defects Monitoring Network, we examined the total prevalence ratio (TPR), perinatal prevalence ratio (PPR) and percentages of prenatally identified cases and of terminations by periods (before and after 2003), birth area, gender and maternal-age classifications.

RESULTS

Down syndrome TPR was 3.05 per 10 000 births during 2003 to 2011, with significant differences between urban-rural, gender and maternal-age groups. DS PPR during 1996 to 2011 was 1.99 per 10 000, presenting an increasing trend till 2003 but a decreasing tendency since then. The proportion of DS diagnosed prenatally increased from 7.55% during 1996 to 2002 to 47.70% during 2003 to 2011, varying by birth area and maternal age. During 2003 to 2011, the high termination rate led to 55% reduction in the overall DS PPR and 62% and 36% decreases in urban and rural PPRs.

CONCLUSION

The important reduction in the PPR suggests that current strategies in China for the prenatal screening and diagnosis of DS are effective. However, significant urban-rural variations in TPR and PPR indicate an urgent need to strengthen prenatal care for DS in rural regions.

Senile myoclonic epilepsy: delineation of a common condition associated with Alzheimer's disease in Down syndrome

In Down syndrome (DS), epilepsy is frequent in all age classes and is recognized as a significant cause of additional handicap and morbidity. Longer life expectancy has led to the recognition of the high incidence of both Alzheimer's disease and seizures in elderly persons with DS. Neuropathological markers of AD are found in all DS brains and clinical symptoms of AD become apparent by the age of 60 years and above in over 50% of DS subjects. Following preliminary description of myoclonic seizures and/or myoclonic epilepsy in isolated cases or small series, we wish to report the diagnostic criteria, treatment and prognosis of a specific and recognizable form of epilepsy associated with AD in a larger group of middle-aged to elderly DS patients. This markedly under-recognized entity may indeed concern an already large and steadily increasing number of patients. We reviewed all medical records of patients with DS referred to our centers (Centre Saint Paul-Gastaut, Marseille; Epilepsy Unit, Montpellier University Hospital; Department of Neurology, Hospital General de Asturias, Oviedo) since 1995. DS had been diagnosed in all at birth, and all presented with the typical morphological changes associated with DS. We selected all cases (18) referred as adults with new onset of myoclonic jerks (MJ) and/or behavioral or cognitive deterioration (CD).