Bilateral Duane's syndrome Type 1 in siblings: Case report.

Duane's rectraction syndrome type 1 is a congenital eye movement disorder. The syndrome is unilateral in 82%. Most cases are sporadic, but familial cases have been estimated at 10% by most authors. We report a case of two siblings both with bilateral Duane's syndrome type 1. To our knowledge, several examples of bilateral familial Duane's syndrome exist in literature. Hereditary patterns of Duane syndrome ad familial occurrence with dominant inheritance patterns have been described. Abnormalities on chromosomes 4, 8 and 22 have been associated with Duane's retraction syndrome. Certainly, Duane's syndrome occurs in autosomal dominant mode; this case is therefore, a new germinal mutation. The other possibility is that it is an autosomal recessive mode and we think there are only few cases suggesting this mode of inheritance. We report our experience about these new cases.