Direct sequencing of PCR products derived from cDNAs for the proα1 and proα2 chains of type I procollagen as a screening method to detect mutations in patients with osteogenesis imperfecta

More than 150 mutations in the genes for type I procollagen have been found in unrelated patients with osteogenesis imperfecta (OI), but mutations have been difficult to define in many patients with the mildest forms of the disease. Here, we have used robotically automated sequencing of the cDNAs for type I procollagen to screen for mutations in 12 patients suspected of having nonlethal OI (types I, III, and IV). Single base mutations that changed codons for obligate glycine residues were found in seven of the patients. Altogether, we analyzed 4,379 bp of sequences of both alleles of the proα1(I) collagen (8,758 bp of allelic sequences) and 4,200 bp of sequences of both alleles of the proα2(I) collagen (8,400 bp of allelic) from each patient.