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Clinical characteristics of 8p inversion duplication and other 8p rearrangements

University of British Columbia

The main goal of the project reported in this thesis is to summarize the current knowledge of the 8p inversion duplication clinical features, to add observations of our own patients, and to correlate the resulting clinical definition with the new information on the molecular analysis of these cases. I present detailed clinical and cytogenetic findings of four patients with 8p inversion duplication, three of which were previously unreported. Two of these patients had an atypical inverted chromosome. In this atypical variant the center of symmetry was found to be more distal on the 8p arm of chromosome 8 so that the portion of 8p23.2 was duplicated in addition to more proximal bands. The report of our two patients is the first focused on this variant. The secondary goal of this thesis was to determine if these variants could be distinguished from the common form in order to add to our knowledge regarding the critical region responsible for the abnormal phenotype in this group of patients. After a detailed clinical comparison of the two types of 8p inversion duplication, I found that in one of the patients with the atypical variant, the physical features were not clearly different from the common type, although the developmental deficit was less marked. In the second patient with the atypical variant the developmental delay and dysmorphism were minimal. In this case the duplication was short, terminating in 8p21.3 band. This case might point to the more exact location of the critical region on 8p. A cosmid 153G8, containing repetitive sequences hybridizing to 4p and to 8p, was used as FISH probe in four cases of 8p inversion duplication. In cases A. and B., 153G8 hybridized to the center of symmetry at 8p23.1. In cases C. and D. with the center of symmetry at 8p(23.2), two FISH signals flanked the center of symmetry. This finding provides the evidence that that repetitive sequences are present in the 8p23.1 region, and that in the atypical variant, the center of symmetry is distal to 8p23.1.

Thesis/Dissertation

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2009-05-25

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http://hdl.handle.net/2429/8164

Medical Genetics

University of British Columbia

UBCV

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