Prenatal detection of a rec (21),dup q,inv(21)(p11q22) utilizing FISH
- Integrated Genetics, Miami, FL (United States)
- Integrated Genetics, Framingham, MA (United States); and others
Region-specific probes to chromosomes 13, 18, 21, X, and Y have been used to determine ploidy level in uncultured anmiocytes. The case described here is the first reported instance of an observed trisomic hybridization pattern in a fetus with a recombinant chromosome 21. The 30-year-old G3P010 patient was referred at 13 weeks gestation due to abnormalities seen on ultrasound (cystic hygroma and edema surrounding the head and body). Amniotic fluid was submitted for aneuploidy detection for chromosomes 13, 18, 21, X & Y by FISH in addition to cytogenetic analysis. Molecular analysis with a chromosome-specific 21q22.3 probe showed a hybridization pattern in which 89% of hybridized nuclei had three signals, consistent with trisomy 21. Cytogenetic analysis showed a male karyotype with a modal number of 46; one no. 21 showed an abnormal G-banding pattern in the short arm. Subsequent metaphase analysis using the 21q22.3 probe showed hybridization to two regions on an F-group sized chromosome. Maternal chromosome analysis revealed a 46,XX,inv(21)(p11q22) karyotype. The abnormal chromosome 21 seen in the amniocyte cell represents a recombinant chromosome which has resulted from a meiotic crossover. This interpretion is consistent with the FISH results which indicate the presence of 3 copies of region 21q22.3. FISH analysis in this case was particularly helpful because of the short arms of chromosome no. 21 are highly polymorphic and this rearrangement was fairly subtle.
- OSTI ID:
- 133775
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0508
- 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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