Severe myopia, either congenital or presenting in infancy, is present in almost every patient and requires corrective lenses. Ophthalmologic exams are recommended yearly and should include periodic fundoscopy. The optic disk and peripapillary appearance in Donnai-Barrow syndrome is characterized by thin emanating vessels and multiple rings of depigmentation obscuring the edge of the reduced neuroretinal rim. Retinal detachment is relatively common. Prophylactic peripheral barrier photocoagulation has been successfully performed in some patients to prevent further detachments. Subcapsular opacity and cataracts are possible.
Congenital or early-onset hearing loss is present in almost every individual. It is moderate or profound and can be progressive. Periodic evaluation is recommended. Treatment with hearing aids or cochlear implants have been successful.
Developmental delay is variable in affected individuals. The presence and degree of learning disability must be assessed before and after the optimization of the sensory deficiencies to determine the most effective educational support. Sign language has been used to facilitate communication in the classroom and in other setting.
Chronic proteinuria and tubular dysfunction may result in irreversible tubular damage in some DBS patients. Focal segmental glomerulosclerosis has been reported in at least two patients. Periodic assessments of renal function are recommended. The presence of type-3 Carbonic Anhydrase (CAIII) in the urine has been proposed by Dachy and colleagues as an early marker of proximal tubular cell injury before changes in renal function or morphology. Nephrolithiasis, nephrocalcinosis, and renal rickets have also been reported.