THE INCIDENCE OF UNIPARENTAL DISOMY ASSOCIATED WITH INTRAUTERINE GROWTH-RETARDATION IN A COHORT OF 35 SEVERELY AFFECTED BABIES

OBJECTIVE: Our purpose was to screen for uniparental disomy 35 babies with idiopathic intrauterine growth retardation < 5th percentile. STUD Y DESIGN: The placenta and the baby's blood were conventionally karyot yped. Deoxyribonucleic acid from the parents, the baby's blood, and th e placenta were then screened for uniparental disomy for 12 candidate chromosomes with use of chromosome-specific polymorphic deoxyribonucle ic acid markers. RESULTS: Two cases of maternal uniparental disomy for chromosome 16 were found associated with confined placental mosaicism for chromosome 16. No other uniparental disomy was found for any of t he 12 chromosomes tested. Four structural chromosome abnormalities wer e also found in this cohort through standard karyotyping. CONCLUSION: Uniparental disomy for the chromosomes tested does not explain the eti ology of the majority of cases of intrauterine growth retardation < 5t h percentile. Maternal uniparental disomy for chromosome 16 accounts f or 5% of this cohort. Structural chromosomal abnormalities are also mu ch higher than expected at 11%.