The challenge of axonal path-finding.

Congenital syndromes of altered nervous system connectivity are reviewed along with recent findings on axonal growth: achiasma, congenital nystagmus, congenital horizontal gaze palsy, mirror movements and the syndromes of Kallmann, Wildervanck, Duane and Marcus Gunn. Identical guidance molecules are most likely involved in making axonal connections after injury and during development. Thus, investigations into variants of connectivity may help develop strategies to treat disconnections of axons in the adult.