Paternal origin of trisomy 21 following intracytoplasmic sperm injection (ICSI).

One important aspect in the debate on the genetic risks associated with intracytoplasmic sperm injection (ICSI) is the possible increased rate of chromosomal abnormalities in resulting pregnancies. ICSI was performed in a 27 year old man with asthenoteratozoospermia and his 25 year old wife. There was a spontaneous miscarriage at 9 weeks of gestation. Cytogenetic investigation revealed trisomy 21. Analysis of two polymorphic microsatellite markers showed that the additional chromosome was paternal. This is in contrast to the fact that the vast majority of trisomic concepti are maternal in origin. Identifying the parent of origin in trisomic conceptions achieved by ICSI may reveal whether ICSI is associated with an increased risk of paternally derived aneuploidy.