Uniparental isodisomy for paternal 7p and maternal 7q in a child with growth retardation
- Perkin Elmer Corp., Foster City, CA (United States) Univ. of California, San Francisco, CA (United States)
- Univ. of California, San Francisco, CA (United States)
Uniparental isodisomy resulting from the simultaneous presence of isochromosomes of the p and q arms of a chromosome and absence of a normal homologue is an exceptionally rare event. The authors have observed a growth-retarded female infant in whom the normal chromosome 7 homologues were replaced by what appeared cytogenetically to be isochromosomes of 7p and 7q. Polymorphic microsatellite loci spanning the length of 7p and 7q were analyzed in the proband and her parents to ascertain the parental origin and extent of heterozygosity of the proband's rearranged chromosomes. These studies demonstrated that the 7p alleles of the proband were derived only from the father, the 7q alleles were derived only from the mother, and there was homozygosity for all chromosome 7 loci analyzed. The mechanisms leading to the formation of the proband's isochromosomes could reflect abnormalities of cell division occurring at meiosis, postfertilization mitosis, or both. The authors believe that the present case may result from incomplete mitotic interchange in the pericentromeric regions of chromosome 7 homologues, with resolution by sister-chromatid reunion in an early, if not first, zygotic division. Phenotypically, the proband resembled three previously reported cases of maternal isodisomy for chromosome 7, suggesting that lack of paternal genes from 7q may result in a phenotype of short stature and growth retardation. 76 refs., 5 figs., 2 tabs.
- OSTI ID:
- 6872589
- Journal Information:
- American Journal of Human Genetics; (United States), Vol. 55:2; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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