title: Preimplantation diagnosis of inherited disease by embryo biopsy: an update of the world figures.
abstract: OBJECTIVE
  Cleavage stage embryo biopsy and preimplantation diagnosis was first reported five years ago. The annual collation of the world figures for centres offering this procedure is important to continually assess the efficiency and success of the biopsy, diagnosis and pregnancies obtained.
  
  
  METHODS
  Data was collected from 14 centres worldwide. The largest series of diagnosis has been performed for those patients carrying X-linked disease where the embryos have been sexed either by PCR or FISH. PCR has also been used for the specific diagnosis of a number of single gene defects, mainly for cystic fibrosis but also for the diagnosis of Lesch Nyhan syndrome, Fragile X, Duchenne muscular dystrophy, Tay Sachs, haemophilia and RhD blood typing.
  
  
  RESULTS
  For PCR sexing, a total of 62 cycles have been performed with 14 pregnancies, 8 deliveries and 11 babies born. For FISH sexing, 70 cycles have resulted in 15 pregnancies, 8 deliveries and 11 babies born. For the specific diagnosis of single genes defects, a total of 65 cycles resulted in 21 pregnancies, 12 deliveries and 12 babies born. Overall, 197 cycles were performed, with 171 embryo transfers (86%), 50 pregnancies (25% per cycle, 29% per transfer), 28 deliveries and 34 babies born.
  
  
  CONCLUSIONS
  New methods are being developed to increase the scope of preimplantation diagnoses that can be offered. From next year, the biochemical and miscarriage rates will also be recorded.
authors.affiliation: Department of Genetics and Biometry, Galton Laboratory, University College, London, England.
authors.forename: J C
authors.initials: JC
authors.lastname: Harper
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D001755:Blastocyst; D004624:Embryo Transfer / Q000706:statistics & numerical data; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D005315:Fetal Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics / Q000517:prevention & control; D030342:Genetic Diseases, Inborn / Q000175:diagnosis* / Q000196:embryology / Q000453:epidemiology / Q000235:genetics / Q000517:prevention & control; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011296:Prenatal Diagnosis / Q000706:statistics & numerical data*; D012743:Sex Preselection