|Programm||"Degeneration und Regeneration– Grundlagen, Diagnostik und Therapie"|
Etiology of congenital ocular motor disorders with synkinesis. Actual aspects.
Congenital ocular motor disorders with synkinesis comprise Duane Syndrome DURS, fibrosis of extraocular muscles CFEOM, and Marcus Gunn jaw winking. Significant progress in disclosing the etiology of such disorders are being achieved by at least 4 different approaches: (1) differential analysis of distinct populations of neurons that control specific types of eye movements, (2) deteciton of specific properties of eye muscles, (3) detection of brainstem abnormalities with modern imaging methods and neuropathological examination, and (4) genetic analyses that ultimately disclose the molecular etiologies (Engle and Leigh 2002). The autosomal recessive form of CFEOM, CFEOM3, is associated with mutations in the homeodomain transcription factor ARIX (Nakano et al. 2001). Gene expression studies in mice and zebrafish have shown selective expression in the nuclei of Nn.III and IV. The autosomal dominant form of CFEOM is genetically heterogeneous, 2 gene loci have been assigned at present (FEOM1, FEOM3). The genes have yet to be identified. Okihiro syndrome represents the association of forearm malformations and features of DURS. Recently, heterozygous SALL4 mutations have been detected in this autosomal dominantly inherited syndrome (Kohlhase et al. 2002). Because of similarities of Okihiro syndrome with thalidomide embryopathy, patients with this condition have b