Osteogensis imperfecta type I is commonly due to a COLIAI null allel of type I collagen
- Univ. of Iowa, Iowa City, IA (United States)
- Univ. of Washington, Seattle, WA (United States)
Dermal fibroblasts from most individuals with osteogenesis imperfecta (OI) type I produce about half the normal amount of type I procollagen, as a result of decreased synthesis of one of its constituent chains, pro[alpha](I). To test the hypothesis that decreased synthesis of pro[alpha](I) chains results from mutations in the COL1A1 gene, the authors used primer extension with nucleotide-specific chain termination to measure the contribution of individual COL1A1 alleles to the mRNA pool in fibroblasts from affected individuals. A polymorphic Mn/I restriction endonuclease site in the 3'-untranslated region of COL1A1 was used to distinguish the transcripts of the two alleles in heterozygous individuals. Twenty-three individuals from 21 unrelated families were studied. In each case there was marked diminution in steady-state mRNA levels from one COL1A2 allele. Loss of an allele through deletion or rearrangement was not the cause of the diminished COL1A1 mRNA levels. Primer extension with nucleotide-specific chain termination allows identification of the mutant COL1A1 allele in cell strains that are heterozygous for an expressed polymorphism. It is applicable to sporadic cases, to small families, and to large families in whom key individuals are uninformative at the polymorphic sites used in linkage analysis, making it a useful adjunct to the biochemical screening of collagenous proteins for OI. 40 refs., 3 figs., 1 tab.
- OSTI ID:
- 5044332
- Journal Information:
- American Journal of Human Genetics; (United States), Vol. 51:3; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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