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April 1982

The Lessons of Polyploidy: Relation to Congenital Asymmetry and the Russell-Silver Syndrome

Author Affiliations

Department of Pediatrics State University of New York Upstate Medical Center Syracuse, NY 13210

Am J Dis Child. 1982;136(4):292-293. doi:10.1001/archpedi.1982.03970400010002

Elsewhere in this issue (p 367), Pai et al report still another phenotypic manifestation of triploidy in man: increased RBC indices. This can be added to those already described in triploidy, such as increased size of other types of cells,1 arborizing polyps of the amnion,2 ocular colobomata, asymmetry, syndactyly of fingers and toes, and intrauterine growth retardation.3 Most observations have been made on patients with diploid-triploid mosaicism, since the longest known survival in a case of pure triploidy is five months.4

Triploidy is a triplication of each chromosome, rather than the duplication seen in the normal diploid set. Thus, the sex chromosomes must be abnormally triplicated (69,XXX or 69,XXY), with the strong possibility of genital abnormalities in the male. That the entirely triploid babies are able to survive even a few months seems remarkable, considering the magnitude of the chromosome changes. Of course, most are never