|Programm||"Degeneration und Regeneration– Grundlagen, Diagnostik und Therapie"|
Retinal Degenerations Causing Severe Visual Handicap in Childhood. Actual Aspects
Lorenz B., Preising M.
The prevalence of blind or severely visually handicapped children is 0.23 to 1.1 per 1000 children (World Health Organization WHO, Prevention of Childhood Blindness, Genf 1992). It is lowest in industrialized countries, and highest in developing countries. The causes are inherited in 16% to 50%. Retinal degenerations are the most frequent hereditary conditions, and account for about 50% in Europe and in Indonesia (Gilbert et al. 1995, Sitorus et al. 2003), 80% in India (Rahi et al. 1995), and 30% in Saudi Arabia (Tabbara and Badr 1985). Leber congenital amaurosis (LCA) is the most severe form of global retinal degenerations. This diagnosis is usually made when infants react only to light (Heckenlively 1988). The fundus may be initially unremarkable. The pupillary reaction may be absent or very sluggish, and nystagmus is a frequent feature. Molecular genetics are increasingly clarifying its etiology. To date, 7 genes have been identified (http://www.retina-international.org/sci-news/disdat.htm), that are associated with LCA or early onset retinitis pigmentosa RP. Detailed analysis of the phenotypes indicates that at least some genotypes are associated with a specific phenotype (Lorenz et al. 2000, Lorenz et al. 2003). Of particular interest is LCA2, a form that is associated with mutations in the RPE65 gene. In a naturally occurring dog model, sub retinal injection of