Purpose: The "nail-patella syndrome" (NPS) is an autosomal dominant hereditary systemic disease. The underlying defect of the LMX1B gene is localised on chromosome 9q34 and causes various typical clinical signs such as onychodysplasia, patella hypoplasia, renal involvement and open angle glaucoma.
Patients: A 42-year-old mother and her 4-year-old son were examined in our hospital in order to exclude ocular involvement in a genetically confirmed "nail-patella syndrome". A clinical examination including corneal topography, gonioscopy as well as measurement of intraocular pressure and bulbus length was performed.
Results: The examination of both patients showed NPS-specific symptoms, however the boy revealed no indications of glaucoma. He suffered from marked amblyopia caused by excessive astigmatism of the left eye and a bilateral moderate hyperopia.
Conclusion: Because of the co-segregation between the syndrome and open angle glaucoma, NPS patients should undergo regular ophthalmological controls including measurement of intraocular pressure. Experiments on mice have shown that mutations of the LMX1B gene result in alterations of several structures of the anterior segments. Thus, the described refraction abnormality could be the consequence of structural changes at the corneal level due to NPS.