Congenital third cranial nerve palsy with prenuclear dysinnervation involving otolithic pathways: Underpinnings of a novel congenital cranial dysinnervation disorder

A 10-year-old boy with unilateral cryptorchidism and renal aplasia displayed features of unilateral congenital pupil sparing third cranial nerve palsy with exotropia manifesting novel dysinnervation encompassing synergistic divergence with upshoot, convergence on attempted upgaze, gaze-evoked phasic conjugate torsion, and gaze-evoked nystagmus. Congenital third nucleus/nerve hypoplasia with secondary dysinnervation is classfied as congenital cranial dysinnervation disorder (CCDD). It is speculated that miswiring between prenuclear structures, otolithic pathways, interstitial nucleus of Cajal (INC), nucleus prepositus hypoglossi, and third and sixth nerve nuclei likely resulted in this novel dysinnervation. Cryptorchidism and renal aplasia if seen may point towards an overlapping phenotype with Duane-radial ray syndrome and acro-renal-ocular/IVIC syndromes.