Abstract 221

Background: Osteogenesis imperfecta (OI) is a generalized connective tissue disorder caused by a qualitative and quantitative impairment of collagen type I. Materials: 17 families with osteogenesis imperfecta were examined (6 of the simplex type and 11 of the multiplex type) in order to evaluate intragenic polymorphic sites in COL1A1 and COL1A2 loci.

Interventions: For COL1A1 the following intragenic markers were used: PCR-RFLP (COL1A1), G/A polymorphism in exon 45 of COL1A1 and C/T polymorphism in +88 position of COL1A1 non-translatable 3′end. For COL1A2 PCR-VNTR was analysed. In five patients with sporadic forms of osteogenesis imperfecta a BESS-T-Scan analysis of cDNA COL1A1 and COL1A2 obtained by RT-PCR from patients fibroblasts was performed.

Results: In 8 out of 11 multiplex families the segregation of the markers revealed correlation with OI, whereas the other 3 were non-informative. The method was not useful in simplex families. The BESS-T-Scan analysis revealed the presence of structural changes in two regions of cDNA COL1A1 in two patients. No quantitative changes referring to COL1A2 gene were noted in any patient.

Conclusions: The study represents the first application of the BESS-T-Scan technique in a molecular diagnosis of OI, which seems to be useful as the screening tool to detect and locate mutations.