Received April 19, 2000
Accepted May 15, 2000

Mutations in the fragile X mental retardation 1(FMR I) gene are diagnosed in the amniotic fluid and chorionic villus sampling of individuais with full mutations and premutations. Transfer of 46,XX IVF generated embryos reduces the probability of FMR l gene full mutation. Carriers with premutation are at increased risk of premature ovarian failure. This report describes the results of 3 IVF attempts in a 38 year old woman with fragile X premutation and reduced ovarian reserve. After signing informed consents, the patient underwent ovulation induction using short Lupron protocol. A 3 colour DNA FISH labelling was performed in single blastomeres obtained at the 8-cell stage embryos with probe set specifically for chromosomes 18, X, and Y. All 8-cell embryos were biopsied and only blastocysts with XX complement were transferred. The mechanical impact of the biopsy did not appear to compromise blastocyst formation. Abdominal chorionic villus sampling (CVS) performed at 12 weeks gestation revealed a 46,XX foetal karyotype and normal alleles (2.8 kb unmethylated fragments) excluding premutation. The patient delivered a normal female infant via caesarean section who weighed 3.9 Kg. ln conclusion, IVF generated femaIe embryos reduce the probability af full fragile X mutation; nevertheless, prenatal diagnosis is still indispensable.