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Congenital cranial dysinnervation disorders (CCDDs) are responsible for 1-2% of infant strabismus cases. Insufficient innervation and misinnervation of aberrant nerve fibres lead to motility restrictions and synkinesis. We present the most common CCDDs and explain their pathogenesis and the resulting clinical features. Furthermore, we emphasize essential diagnostic steps and treatment aspects.

Currently, different syndromes with congenital, nonprogressive, sporadic, or familial developmental abnormalities of the cranial nerves and its nuclei are classified as congenital cranial dysinnervation syndromes (CCDD). One of these syndromes, congenital fibrosis of extraocular muscles (CFEOM), is characterized mainly by bilateral ophthalmoplegia of the oculomotor and trochlear nerves. Within the scope of an overview, the case of a 60-year-old patient with congenital fibrosis of extraocular muscles type 1 (CFEOM1) with autosomal dominant inheritance and typical phenotype, but additional progression of the ocular symptoms, is presented. Symptoms were caused by the common C2860-->T mutation in exon 21 of the KIF21A gene on chromosome 12. Further CCDD syndromes include the following phenotypes: congenital ptosis, Duane syndrome, horizontal gaze palsy, Möbius' syndrome, and congenital facial palsy. There are 13 different known gene loci for one of these phenotypes. Five gene products have been identified: the kinesin motor protein Kif21a, the transcription factors ARIX and SALL4, and the carboxypeptidase CPAH.