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.

Down's syndrome: screening and antenatal diagnosis regionally in England and Wales 1989-2008.

Objective: To illustrate regional changes that occurred in screening for Down's syndrome (trisomy 21) in England and Wales from 1989 to 2008.

Methods: The National Down Syndrome Cytogenetic Register has collected data on all ante- and postnatal diagnoses of Down's syndrome in England and Wales since 1989 (n = 27,954). The percentages of (i) diagnoses made antenatally, (ii) antenatal diagnoses that had nuchal translucency (NT) measured, and (iii) antenatal diagnoses in mothers aged 37 and over with advanced maternal age as the sole recorded indication for diagnosis are presented according to where the mother lived (Government Office Region), year of diagnosis (1989-1994, 1995-2000, 2001-2006, 2007-2008), and maternal age (<37 years, ≥37 years).

Trends in Down's syndrome live births and antenatal diagnoses in England and Wales from 1989 to 2008: analysis of data from the National Down Syndrome Cytogenetic Register.

Objectives: To describe trends in the numbers of Down's syndrome live births and antenatal diagnoses in England and Wales from 1989 to 2008. Design and setting The National Down Syndrome Cytogenetic Register holds details of 26488 antenatal and postnatal diagnoses of Down's syndrome made by all cytogenetic laboratories in England and Wales since 1989.

Interventions: Antenatal screening, diagnosis, and subsequent termination of Down's syndrome pregnancies.