Cytogenetic and molecular characterization of a subtle familial 9q duplication in affected and normal individuals
- Yale Univ. School of Medicine, New Haven, CT (United States)
- Yale Univ. School of Medicine, New Haven, CT (United States); and others
A subtle duplication of 9q [dup(9)(q21.1{yields}21.2)] was identified in two unrelated families. In family A, it was present in the proband with congenital neuroblastoma and no other physical abnormalities, as well as his clinically normal father and paternal aunt. In family B, a similar dup(9q) was found in an eleven-year-old male with developmental and mental retardation and his phenotypically normal mother. All other chromosomes in those individuals studied appeared normal. The extra positive G-band was C-band negative suggesting its euchromatic nature which was further confirmed by two-color FISH using two satellite DNA probes specific for chromosome 9 centromere and heterochromatin (9qh). Due to the subtlety of this duplication, FISH with a chromosome 9-specific library was performed to establish that it is not more than a simple duplication. Hybridization signals, even throughout both chromosome 9s of patients and their normal relatives, were observed and were not detected on any other chromosomes. Thus, the extra band is of chromosome 9 origin and can be best interpreted as part of 9q21.1-21.2 based on high resolution karyotypes. There are two reports describing duplications involving 9q13-22 in normal individuals and abnormal family members. However, the origin and euchromatic nature of these chromosome findings have yet to be confirmed by further molecular studies. Euchromatic variant bands, in most reported cases, represent an extra band within the elongated 9qh region and are accompanied by an extra C-band (9qh+). The dup(9)s identified in our two families are apparently different than previously reported 9qh+ variant and may represent a rare variant whose clinical significance remains unclear.
- OSTI ID:
- 133712
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0443
- 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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