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J Med Genet 39:e54 doi:10.1136/jmg.39.9.e54
  • Electronic letters

Survival in trisomy 13 and trisomy 18 cases ascertained from population based registers

  1. C M Brewer1,
  2. S H Holloway2,
  3. D H Stone3,
  4. A D Carothers4,
  5. D R FitzPatrick2,4
  1. 1South Western Regional Genetics Service - Devon and Cornwall, Royal Devon & Exeter Hospital, Exeter EX2 5DW, UK
  2. 2South-East Scotland Clinical Genetics Services, Molecular Medicine Centre, Western General Hospital, Edinburgh EH4 2XU, UK
  3. 3Paediatric Epidemiology and Community Health (PEACH) Unit, University of Glasgow, Royal Hospital for Sick Children, Yorkhill, Glasgow G3 8SJ, UK
  4. 4MRC Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, UK
  1. Correspondence to:
 Dr D R FitzPatrick, MRC Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, UK;
 david.fitzpatrick{at}hgu.mrc.ac.uk

    A lthough long term survivors are well documented, infants with the autosomal trisomies 18 (Edwards syndrome) or 13 (Patau syndrome) usually die in the first few days or weeks of life. Accurate estimates of life expectancy are few, particularly in the case of trisomy 13. There have been six population surveys of survival in trisomy 18, comprising 430 unselected cases.1–6 In contrast there have been only two such studies of trisomy 13 involving 35 cases.4,7 A reliable estimate of survival time is important when counselling parents following a pre- or postnatal diagnosis. The fact that a significant proportion of infants succumb within the first 24 hours is a major contributing factor to the short median survival time. Given this fact, a means of revising the estimate of survival when an infant is already several days old is important. Using information available on infants with trisomy 13 or 18 born in Scotland from 1974 to 1997, we have calculated median survival times in this population and prepared revised figures which take into account continued survival.

    PATIENTS AND METHODS

    Cases were ascertained from two sources, the Scottish Trisomy Register 1989-1997 and the Glasgow Register of Congenital Anomalies 1974-1989. The Scottish Trisomy Register was established in 1989 and is a database of autosomal trisomies in Scotland; information is collected from the Scottish service laboratories and includes name, date of birth, type of sample, karyotype, and whether liveborn.8,9 Dates of death are ascertained separately. The Glasgow Register of Congenital Anomalies is a multisource, population based congenital anomaly database of offspring of mothers resident in the Greater Glasgow Health Board area. Diagnostic validation by trained registry workers is performed on all notified cases. Only liveborn, non-mosaic free trisomies, both pre- and postnatally ascertained, were included in this study. These two sources provide …

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