Familial Congenital Facial Synkinesis Due to 12q Duplication: A Case Report and Literature Review.

Inverse Marcus Gunn phenomenon is a rare form of congenital facial synkinesis in which jaw movement temporarily elicits ptosis, either unilateral or bilateral. This phenomenon is presumed to result from dysinnervation of facial muscles during development of the nervous system. We describe 2 brothers, both with inverse Marcus Gunn phenomenon in the context of multiple other congenital anomalies, all presumed secondary to a chromosomal abnormality involving 12q duplication and 1p36 deletion.