Nine (9) marker chromosomes diagnosed prenatally in 6,234 cases and their outcome
- Medical Genetics Emanuel Hospital & Health Center, Portland, OR (United States); and others
Marker chromosomes have a frequency of 0.06-0.08 per 1000 in prenatal diagnosis specimens and often pose a dilemma in counseling because of an inability in most cases to identify the marker chromosome cytogenetically. An attempt is made in this study to characterize the marker chromosomes we found in our prenatal diagnosis from 1991-1993. We diagnosed 9 cases of marker chromosomes out of 6,234 prenatal diagnostic studies. Eight cases were patients referred because of advanced maternal age and one (GS) was referred after abnormal ultrasound findings. Six cases were mosaic for a marker. Seven of these patients continued their pregnancies, one patient had a dizygotic twin pregnancy (CM) where the co-twin had normal chromosome complement. Parental chromosomes on all of these cases were normal (in one couple the wife (VA) had a 46,XX/47,XXX karyotype). Special staining methods used for identifying the markers were DAPI/DA, NOR, C, R and FISH. Of the seven pregnancies that were continued, two babies were born with complications, and one of them (GS) subsequently died at six months of age. The marker in this baby was identified as chromosome 14 in origin by FISH. The other (LM) baby was born with extrophy of the bladder. The marker in the dizygotic twin (CM) was identified as chromosome 13 in origin by FISH. The rest of the pregnancies with a marker chromosome had a normal outcome with phenotypically normal babies without any complications. By parental report, babies were developing normally at 1 day (VA), 4 months (CM), 8 months (CL), 9 months (KP) and 22 months (EN) of age. Results of FISH studies on these cases will be presented along with a detailed table.
- OSTI ID:
- 134605
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-1342
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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