Hereditary collagen disease a cause of glaucoma
The mutations in collagen genes that cause osteogenesis imperfecta (OI) also appear to cause primary open-angle glaucoma (POAG) in affected individuals, indicating that collagen abnormalities may also underlie glaucomatous pathology, said Emer Doolan MD at the Annual Conference of the Irish College of Ophthalmologists.
Dr Doolan, who is based at the Mater Misericordiae University Hospital Dublin, noted that OI comprises a group of inherited disorders characterised by bone fragility and the ocular finding of ‘blue sclera’ in addition to numerous ocular manifestations. The OI conditions are cased by autosomal dominant mutations in the COL1A1 and Col11A2 genes in 90% of cases. The types of collagen the genes code for are found in the bone skin sclera and cornea.
Dr Doolan and her associates carried out genetic testing and corneal hysteresis and central corneal thickness measurements in eight members of an OI-affected family they encountered in their clinical practice
They found that all six family members affected with OI were heterozygous for a pathogenic mutation in intron 26 of the COL1A1 gene. In addition, two of the affected individuals had developed POAG at ages 40 and 45 years respectively, and all of those with OI had significantly thinner CCT and lower CH than normal.
Dr Doolan therefore recommended screening for glaucoma in all OI-affected individuals, and that the testing should include including corneal hysteresis measurements