Analysis of the Origin of the Extra Chromosome in Trisomy 8 in 4 Cases of Spontaneous Abortions

Abstract

Objective: To determine the origin of the extra chromosome in trisomy 8 in spontaneous abortions. Methods: We analyzed 4 cases of nonmosaic trisomy 8 in 1st-trimester spontaneous abortions and their parents with DNA polymorphism analysis using microsatellite DNA markers. Results: In 3 cases the extra chromosome was maternal in origin and in 1 case paternal in origin. In 2 of the cases the nondisjunction had occurred in maternal meiosis, while the other 2 cases were consistent with a postzygotic (mitotic) origin of the additional chromosome. Conclusion: Although a small number of cases studied, these results suggest differences from the common autosomal trisomies 21, 18, 16, and 13 where the vast majority of cases are due to errors in maternal meiosis.

Origin of nondisjunction in trisomy 8 and trisomy 8 mosaicism

“…Preliminary results of nondisjunction analysis for the spontaneous abortions have been reported elsewhere. 33 The prenatal diagnoses were chorionic villus samplings (CVS). One was due to advanced maternal age ( …”

Trisomy 8 mosaicism in a patient born to a mother with 47,XXX

“…Since uniparental disomies have been shown to cause anomalies and mental retardation, it could, therefore, be a factor in phenotypic variability. Concerning the mechanism of formation, it is known that common autosomal trisomy (including mosaic) are due to errors in maternal meiosis in majority of the cases [Nicolaidis et al, 1998]. In trisomy 8 and trisomy 8 mosaicism, the studies carried out by Karadima et al [1998] demonstrated that nondisjunction was probably due to mitotic (postzigotic) duplication.…”

Trisomy 8 mosaicism in the placenta: A Danish cohort study of 37 cases and a literature review

“…2 Trisomy 8 mosaicism (T8M) in the live birth is almost always the result of postzygotic non-disjunction with the extra chromosome being either maternal (2:3) or paternal (1:3) in origin, while T8M of meiotic origin is almost exclusively seen in spontaneous abortions. [2][3][4][5][6][7] However there have been a few reports of T8M of meiotic origin in live patients who do not exhibit any of the common features of trisomy 8 mosaicism. 8,9 T8M in the live born population (Warkany syndrome) appears with a prevalence between 1:25,000 and 1:50,000.…”