Uniparental disomy as an explanation of presumptive low penetrance
- Univ. of Helsinki (Finland)
Reduced penetrance has been proposed to account for an observed deficiency of affected individuals in the recessively inherited developmental disorder, cartilage-hair hypoplasia (CHH, MIM No.250250). We recently mapped the gene for CHH to the short arm of chromosome 9, and have shown that reduced penetrance is an unlikely explanation as no unaffected sibs with a genotype identical to that of the affected children were observed at any of the closest marker loci studied. Here we report that two CHH patients out of 45 Finnish uniplex patients had maternal uniparental disomy (UPD) for chromosome 9. The patients were tested with eighteen chromosome 9-specific markers and no paternal contribution was observed in any of the informative meioses. Paternity was confirmed by typing markers from all autosomes other than chromosome 9, and the X chromosome. Both patients were homozygous for all chromosome 9 markers with the exception of one of them who was heterozygous for the maternal alleles at two marker loci on 9q. Further studies will show what proportion of individuals homozygous for CHH is caused by UPD allowing its quantitative significance to be assessed. Based on the data presented here we propose UPD as a main mechanism contributing to the observed deficiency of affected individuals in CHH families.
- OSTI ID:
- 133290
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0017
- 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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