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.