Mackay K, Lund A M, Raghunath M, Steinmann B, Dalgleish R
Department of Genetics, University of Leicester, UK.
Hum Genet. 1993 Jun;91(5):439-44. doi: 10.1007/BF00217768.
A patient with perinatal lethal osteogenesis imperfecta (OI) type II has been studied in order to identify the causative mutation. By analysis of the type I collagen produced by cultured fibroblasts from the patient, the defect was mapped to alpha 1 cyanogen bromide peptide 7, a region corresponding to 271 amino acid residues of either the alpha 1(I) or alpha 2(I) collagen chains. Polymerase chain reaction (PCR) amplification of the corresponding region of the alpha 1(I) mRNA followed by single-strand conformation polymorphism analysis of restriction enzyme digestions of the PCR products allowed further mapping of the mutation to a small region of COL1A1. A heterozygous transversion of G to T within the last glycine codon of exon 32 was identified by DNA sequence analysis. This resulted in the substitution of glycine-565 by a valine residue, disrupting the repeating Gly-Xaa-Yaa sequence that is obligatory for correct formation of the collagen molecule. The mutation was shown to have occurred de novo and is thought to result in the OI phenotype.
为了确定致病突变，对一名患有围生期致死性II型成骨不全症（OI）的患者进行了研究。通过分析患者培养的成纤维细胞产生的I型胶原蛋白，发现缺陷位于α1溴化氰肽7，该区域对应于α1（I）或α2（I）胶原蛋白链的271个氨基酸残基。对α1（I）mRNA的相应区域进行聚合酶链反应（PCR）扩增，然后对PCR产物进行限制性酶切的单链构象多态性分析，可将突变进一步定位到COL1A1的一个小区域。通过DNA序列分析，在第32外显子的最后一个甘氨酸密码子内发现了一个G到T的杂合颠换。这导致甘氨酸-565被缬氨酸残基取代，破坏了胶原蛋白分子正确形成所必需的重复Gly-Xaa-Yaa序列。该突变显示为新发突变，被认为导致了OI表型。
