Genomic imprinting as a probable explanation for variable intrafamilial phenotypic expression of an unusual chromosome 3 abnormality
- Univ. of Virginia Health Science Center, Charlottesville, VA (United States); and others
We present a 4 generation family in which an abnormal chromosome 3 with dup(3)(q25) segregated from great-grandmother to grandmother to son without phenotypic effect. The son`s 2 daughters have dysmorphic features, mild developmental delays and congenital heart disease. Both girls have the abnormal chr. 3 but are the only family members with the abnormality to have phenotypic effects. An unaffected son of the father has normal chromosomes. FISH with whole chromosome paints for chromosomes 1, 2, 6, 7, 8, 14, 18, and 22 excluded these as the origin of the extra material. Chromosome 3-specific paint revealed a uniform pattern, suggesting that the extra material is from chromosome 3. Comparative genomic hybridization and DNA studies are pending. Possible explanations for the discordance in phenotypes between the 4th generation offspring and the first 3 generations include: an undetected rearrangement in the previous generations that is unbalanced in the two affected individuals; the chromosome abnormality may be a benign variant and unrelated to the phenotype; or, most likely, genomic imprinting. Genomic imprinting is suggested by the observation that a phenotypic effect was only seen after the chromosome was inherited from the father. The mothers in the first two generations appear to have passed the abnormal chr. 3 on without effect. This is an opportunity to delineate a region of the human genome affected by paternal imprinting.
- OSTI ID:
- 133681
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0411
- 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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