Molecular cytogenetic analysis of the 18q- syndrome
- Thomas Jefferson Univ., Philadelphia, PA (United States)
- Univ. of Pennsylvania, Philadelphia, PA (United States); and others
The 18q- syndrome is a partial aneuploidy disorder that is caused by a deletion of the distal part of the long arm of chromosome 18 (18q). Classically, patients exhibit growth deficiency, midfacial hypoplasia, carp-like mouth, developmental delay, and mental retardation. We report on the analysis of 33 patients with a deletion of 18q. The patients exhibit a wide variety of clinical symptoms and severity. The location and size of each deletion was determined by fluorescence in situ hybridization using 200 lambda phage clones that had been mapped to distinct regions of the chromosome. Deletion breakpoints ranging from 18q21.2 to 18q22.3 were observed. None of the deletions were interstitial based on the lack of hybridization of a 18q telomeric YAC clone to the deleted chromosome 18 homologue. A possible role for genomic imprinting was investigated by determination of the parental origin of the deletion using microsatellite markers. An equal frequency of paternally-derived deletions and maternally derived deletions was observed. In contrast to our previous findings with the larger patient sample, no correlation could be made between the size of the deletion, the parental origin of the deletion, the severity of the developmental delay, and the presence of specific clinical features. These results suggest that a critical region for the 18q- syndrome maps to 18q22.3-qter, a region that confers the potential for having the different clinical features associated with the syndrome. Thus, accurate prognosis can not be made based on the size of the deletion and other factors such as the environment and genetic background may have a large influence on the severity of the disorder.
- OSTI ID:
- 133764
- 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
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