Non-Mosaic Trisomy 20
Non-Mosaic Trisomy 20 (NMT20) is a chromosome abnormality where all cells contain three copies of chromosome 20.
NMT20 is not normally compatible with advanced fetal development.
The article below describes a pregnancy where NMT20 was detected at amniocentesis and the fetus was examined at autopsy.
| Prenatal Diagnosis 2001 May;21(5):387-9 | |
Non-mosaic trisomy 20 presenting at 21 weeks' gestation as a thoraco-abdominal mass.Driggers RW, Bernstein H, Lantz M, Stetten G, Escallon CS, Perlman E, Blakemore KJ.Non-mosaic trisomy 20 is rare in fetuses surviving beyond the first trimester. We report a case of a fetus with non-mosaic trisomy 20 in amniotic fluid cultures obtained during the prenatal evaluation of an unusual thoraco-abdominal mass which was found at autopsy to be pulmonary sequestration. Gross inspection and autopsy of the fetus revealed multiple anomalies.
An older article describes a terminated pregnancy in which NMT20 was detected at amniocentesis, and only minor physiological anomalies were detected in the fetus post-termination.
| Clinical Genetics 1989 Apr;35(4):233-6 | |
Non-mosaic trisomy 20 in amniotic fluid cultures with minor anomalies in the fetus.Myers TL, Prouty LA.A non-mosaic trisomy 20 was discovered in all cells in two separate cultures from an age-related genetic amniocentesis. Karyotypes of cells obtained via amniocentesis at the time of termination and of cells cultured from the placenta gave the same unambiguous results. However, the fetus, under macro- and microscopic analysis, showed only two minor anomalies: left simian crease and low-set ears. These findings are more suggestive of a normal or at most mosaic trisomy 20 state. The significance of this finding for prenatal diagnosis is discussed. What is Trisomy 20?
Trisomy 20 Mosaicism Amniocentesis and T20M
