OBJECTIVE: To assess the implications of a change in prenatal diagnosis policy from full karyotype analysis to rapid trisomy testing for women referred primarily for increased risk of Down's Syndrome. DESIGN: Retrospective collection and review of data. SETTING: The four London Regional Genetics Centres. POPULATION: Pregnant women (32,674) in the London area having invasive prenatal diagnosis during a six-year three-month period. METHODS: Abnormal karyotypes and total number of samples referred for raised maternal age, raised risk of Down's Syndrome following serum screening or maternal anxiety were collected. Abnormal karyotypes detected by molecular trisomy detection were removed, leaving cases with residual abnormal karyotypes. These were assessed for their clinical significance. Pregnancy outcomes were ascertained by reviewing patient notes or by contacting obstetricians or general practioners. MAIN OUTCOME MEASURES: Proportion of prenatal samples with abnormal karyotypes that would not have been detected by rapid trisomy testing, and the outcome of those pregnancies with abnormal karyotypes. RESULTS: Results from 32,674 samples were identified, of which 24,891 (76.2%) were from women referred primarily for Down's Syndrome testing. There were 118/24,891 (0.47%) abnormal sex chromosome karyotypes. Of the samples with autosomal abnormalities that would not be detected by rapid trisomy testing, 153/24,891 (0.61%) were in pregnancies referred primarily for Down's Syndrome testing. Of these, 98 (0.39%) had a good prognosis (46/98 liveborn, 3/98 terminations, 1/98 intrauterine death, 1/98 miscarriage, 47/98 not ascertained); 37 (0.15%) had an uncertain prognosis (20/37 liveborn, 5/37 terminations; 12/37 not ascertained) and 18 (0.07%) had a poor prognosis (1/18 liveborn, 2/18 miscarriage, 11/18 terminations, 4/18 not ascertained). CONCLUSIONS: For pregnant women with a raised risk of Down's Syndrome, a change of policy from full karyotype analysis to rapid trisomy testing would result in the failure to detect chromosome abnormalities likely to have serious clinical significance in approximately 0.06% (1 in 1659) cases. However, it should be noted that this figure may be higher (up to 0.12%; 1 in 833) if there were fetal abnormalities in some of the pregnancies in the uncertain prognosis group for which outcome information was not available.
OBJECTIVE: To assess the implications of a change in prenatal diagnosis policy from full karyotype analysis to rapid trisomy testing for women referred primarily for increased risk of Down's Syndrome. DESIGN: Retrospective collection and review of data. SETTING: The four London Regional Genetics Centres. POPULATION: Pregnant women (32,674) in the London area having invasive prenatal diagnosis during a six-year three-month period. METHODS: Abnormal karyotypes and total number of samples referred for raised maternal age, raised risk of Down's Syndrome following serum screening or maternal anxiety were collected. Abnormal karyotypes detected by molecular trisomy detection were removed, leaving cases with residual abnormal karyotypes. These were assessed for their clinical significance. Pregnancy outcomes were ascertained by reviewing patient notes or by contacting obstetricians or general practioners. MAIN OUTCOME MEASURES: Proportion of prenatal samples with abnormal karyotypes that would not have been detected by rapid trisomy testing, and the outcome of those pregnancies with abnormal karyotypes. RESULTS: Results from 32,674 samples were identified, of which 24,891 (76.2%) were from women referred primarily for Down's Syndrome testing. There were 118/24,891 (0.47%) abnormal sex chromosome karyotypes. Of the samples with autosomal abnormalities that would not be detected by rapid trisomy testing, 153/24,891 (0.61%) were in pregnancies referred primarily for Down's Syndrome testing. Of these, 98 (0.39%) had a good prognosis (46/98 liveborn, 3/98 terminations, 1/98 intrauterine death, 1/98 miscarriage, 47/98 not ascertained); 37 (0.15%) had an uncertain prognosis (20/37 liveborn, 5/37 terminations; 12/37 not ascertained) and 18 (0.07%) had a poor prognosis (1/18 liveborn, 2/18 miscarriage, 11/18 terminations, 4/18 not ascertained). CONCLUSIONS: For pregnant women with a raised risk of Down's Syndrome, a change of policy from full karyotype analysis to rapid trisomy testing would result in the failure to detect chromosome abnormalities likely to have serious clinical significance in approximately 0.06% (1 in 1659) cases. However, it should be noted that this figure may be higher (up to 0.12%; 1 in 833) if there were fetal abnormalities in some of the pregnancies in the uncertain prognosis group for which outcome information was not available.
Authors: Celia Badenas; Laia Rodríguez-Revenga; Carme Morales; Carmen Mediano; Alberto Plaja; Ma Mar Pérez-Iribarne; Anna Soler; Núria Clusellas; Antoni Borrell; Ma Ángeles Sánchez; Elisabeth Miró; Aurora Sánchez; Montserrat Milà; Wladimiro Jiménez Journal: J Mol Diagn Date: 2010-10-01 Impact factor: 5.568
Authors: Antina de Jong; Wybo J Dondorp; Daniëlle R M Timmermans; Jan M M van Lith; Guido M W R de Wert Journal: Eur J Hum Genet Date: 2011-06-01 Impact factor: 4.246
Authors: Diane Van Opstal; Marjan Boter; Danielle de Jong; Cardi van den Berg; Hennie T Brüggenwirth; Hajo I J Wildschut; Annelies de Klein; Robert-Jan H Galjaard Journal: Eur J Hum Genet Date: 2008-09-10 Impact factor: 4.246
Authors: Elisabeth M A Boormans; Erwin Birnie; Mariëtte J V Hoffer; Merryn V E Macville; Robert-Jan Galjaard; Gijsbertha H Schuring-Blom; Shama L Bhola; Karin Huijsdens; Arie Smits; Jan M M van Lith Journal: Arch Gynecol Obstet Date: 2011-05-19 Impact factor: 2.344