X-linked retinoschisis: clinical phenotype and RS1 genotype in 86 UK patients.

BACKGROUND: Inactivating mutations of the gene RS1 lead to X-linked retinoschisis, a progressive retinal dystrophy characterised by schisis within the inner layers of the neuroretina. The mutation spectrum is large and the phenotype variable. AIM: To determine whether there is a correlation between mutation type and disease severity. METHODS: We identified the causative mutation in 86 affected patients and examined each of these patients in detail. Different categories of mutation were compared for each phenotypic characteristic. RESULTS: We found a reduction in visual acuity with increasing age and worsening macular pathology in patients over 30 years old (p <or = 0.001), but there was no correlation between mutation type and severity of disease. Furthermore, we found a wide variation in phenotype even within families. CONCLUSIONS: Identifying the causative mutation in patients with X-linked retinoschisis is helpful in confirming diagnosis and in counselling of family members but cannot be used to predict prognosis for an individual patient.