Identification by FISH of 21q22 duplication in patient with Down syndrome and apparent 46,XX karyotype

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:133786

Yu, Chih-yu; Anyane-Yeoba, K; Warburton, D ^[1]

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1. Columbia Univ., New York, NY (United States)

Karyotype analysis of a 3-day-old child referred for clinical evaluation of Down syndrome was originally reported as normal 46,XX. The child had many features of Down syndrome, including a leukemoid reaction at birth. Because of the strongly suggestive clinical features, and a slightly unusual appearance of the short arm of one chromosome 21, FISH analysis was carried out using a probe specific for the 21q22.3 region (ONCOR). Signal was seen as expected in the distal long arm of both chromosomes 21, but also in the short arm with the morphological variant. DNA analysis with a number of long arm probes confirmed the presence of duplication of a large portion of band 21q22. Parental karyotypes were normal. The mother of this case had declined amniocentesis. However, it is very likely that routine prenatal chromosome analysis would not have detected the duplication, since the short arm was not strikingly different from many normal variants. Only screening with a 21q22 FISH probe (interphase or metaphase) would have predicted the Down syndrome in this child.

• OSTI ID: 133786
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
CHROMOSOMAL ABERRATIONS
DETECTION
DNA
DNA HYBRIDIZATION
DOWNS SYNDROME
FLUORESCENCE
HUMAN CHROMOSOME 21
INFANTS
KARYOTYPE
PROBES
SENSITIVITY