A novel posterior keratoconus with osteogenesis imperfecta by mutation in COL1A1

Background Posterior keratoconus is a rare, non-progressive corneal condition in the posterior surface of the cornea. Also known as keratoconus posticus, it is characterized by thinning of the posterior cornea without ectasia of the anterior cornea. Osteogenesis imperfecta (OI) is a rare inherited connective tissue disease affecting collagen production. The manifestations in OI patients have not been well studied in the case of keratoconus, especially posterior keratoconus. Here, we observe that a clinical patient has the syndrome of OI caused by mutations in the COL1A1 genes and Descemet membrane detachment. Case presentation We report a 27 years old Chinese male with skeletal deformity and hirsutism complained of blurred vision in his left eye for one month. He had hearing loss in his both ears 6 years ago. There were many times of bone fragility history. Cardiac ultrasound indicated cardiac insufficiency. On examination, best corrected visual acuity (BCVA) was 20/40 in the right eye and light perception in the left eye. Slit lamp examination of the left eye showed corneal edema, paracentral corneal thinning without ectasia of the anterior cornea and a peripheral circular band of corneal opacity which was sharply demarcated. Examination of the right eye was normal except a peripheral circular band of corneal opacity as the same as the left eye. Topographic analysis of the cornea has further shown that there are in fact anterior surface changes in posterior keratoconus, including paracentral steepening in the area of the posterior corneal depression with gradual peripheral flattening. Ultrasound biomicroscopy has been shown the local anterior bulging of the posterior corneal surface, thinning of the superior stroma, a central Descemet’s detachment and enhanced stromal reflectivity corresponding to the stromal opacity seen in circumscribed posterior keratoconus. The diagnosis of posterior keratoconus accompanied with bilateral peripheral circular corneal degeneration was made and the patient underwent penetrating keratoplasty of the left eye. After the operation, both anatomic and visual development success were obtained. However, the patient was suffering from overall dysplasia. We speculated that it might be a systemic syndrome. So we performed gene testing of blood samples from patient and his family members after obtaining their informed consent. The results indicated a mutation in the COL1A1 gene (NM_000088.4:exon7:c.572_573 delins AA: p.G191E). Conclusions This is the first report which covers posterior keratoconus occurring in patient with OI. This novel report reminds us the importance of taking eye examinations into consideration in systemic syndrome.