Pathological Findings in the Complete Trisomy 9 Syndrome: Three Case Reports and Review of the Literature

The term "complete trisomy 9" is used to indicate trisomy of the entire chromosome 9 without evidence of mosaicisms. It is a relatively rare chromosomal abnormality because the vast majority of affected pregnancies result in 1st trimester spontaneous abortions. The purpose of this paper is to delineate the complete trisomy 9 syndrome, based on autopsy findings. We performed an exhaustive review of the literature of complete forms of this trisomy with autopsy examination and added 3 new cases from our center with new findings not previously described.