Ophthalmologic and SystemicFeatures in Möbius Syndrome An Italian Case Series

Purpose: To describe clinical features in a large series of Möbius Syndrome (MBS) cases, investigating whether specific neuro-ophthalmologic pattern disease may provide further insight into MBS pathogenesis. Design: Case series. Participants: Fifty-five affected subjects. Methods: To make an MBS diagnosis we followed the criteria recommended in the First Scientific Conference on Möbius Syndrome. Patients who did not meet the minimal criteria were classified as Möbius-like cases and considered separately. Complete ophthalmologic evaluation; eyelid measurements, presence of abnormal tearing and ocular motility were also assessed. Main Outcome Measures: pattern of ocular motility alteration; visual function disturbances; eyelid and tearing defect. Results: Forty-six sporadic cases of true MBS are described, with three specific patterns of ocular motility alterations. Pattern named “A”, consisting of orthotropia in primary position with a complete defect in both abduction and adduction ocular movements, was found in 41% of cases. Pattern named “B” with large angle esotropia, crossed fixation, and a relative sparing of convergence and adduction, was documeted in 50% of cases. Pattern named “C”, characterized by a large angle exotropia in primary position with torcicollis, absence of convergence and vertical eye misalignment, was present in the minority of the patients (9%). Bilateral complete facial nerve palsy with lagophthalmos was present in 83% of patients; lacrimation showed abnormalities in 33% of cases. Visual acuity was good or only moderately impaired in all tested patients. Binocular function was testable in 31/46 patients and all of them showed a complete absence of stereopsis with suppressive scotoma. Conclusions: Based on the observed three different ocular motility defect patterns, we inferred the most compatible site and extension of the brainstem damage. We hypothesized that each pattern may reflect different types of injury likely occurred during embryogenesis. The comparison of the characteristics of our series with those reported in different geographic areas supports the evidence that MBS does not differ phenotypically worldwide.