Digynic triploid infant surviving for 46 days

We report on a triploid infant who survived for 46 days. She had severe int rauterine growth retardation, relative macrocephaly, and a small, noncystic placenta, which are manifestations compatible with type II phenotype. Cult ured amniotic fluid cells, skin fibroblasts, cord blood, and peripheral blo od lymphocytes all showed a nonmosaic 69,XXX karyotype. Analysis of chromos omal heteromorphisms and microsatellite DNA polymorphisms in the infant and her parents indicated that the extra haploid set in the infant resulted fr om nondisjunction at maternal second meiosis. Postzygotic, mitotic nondisju nction was ruled out because of the presence of both homozygous and heteroz ygous markers of maternal origin. A search of the literature demonstrated f ive triploid infants, including the girl we described, who survived 4 weeks or more, and the parental origin of whose triploidy was studied: four were digynic and one was diandric, These findings support the notion that type II triploids are digynic in parental origin and that they survive longer th an type I, diandric triploids. (C) 1999 Wiley-Liss, Inc.