Ophthalmologic and Systemic Features in Möbius Syndrome: An Italian Case Series

Abstract

To describe clinical features in a large series of Möbius syndrome (MBS) cases, investigating whether specific neuro-ophthalmologic patterns of disease may provide further insight into MBS pathogenesis. Observational, prospective study. Fifty-five affected subjects. To make an MBS diagnosis, the criteria recommended in the First Scientific Conference on Möbius Syndrome were followed. Patients who did not meet the minimal criteria were classified as Möbius-like cases and were considered separately. Complete ophthalmologic evaluation, eyelid measurements, presence of abnormal tearing, and ocular motility also were assessed. Pattern of ocular motility alteration, visual function disturbances, and eyelid and tearing defect. Forty-six sporadic cases of true MBS were identified, with 3 specific patterns of ocular motility alterations. Pattern A, consisting of orthotopia in primary position with a complete defect in both abduction and adduction ocular movements, was found in 41% of cases. Pattern B, with large-angle esotropia, crossed fixation, and a relative sparing of convergence and adduction, was documented in 50% of cases. Pattern C, characterized by a large-angle exotropia in primary position with torticollis, 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 impaired only moderately in all tested patients. Binocular function was testable in 31 of 46 patients, and all of them showed a complete absence of stereopsis with suppressive scotoma. Based on the observed 3 different ocular motility defect patterns, the most compatible site and extension of the brainstem damage was inferred. Each pattern may reflect a different type of injury likely occurred during embryogenesis. The comparison of the characteristics of this series with those reported in different geographic areas supports the evidence that MBS does not differ phenotypically worldwide. The author(s) have no proprietary or commercial interest in any materials discussed in this article.