Oculopharyngeal Muscular Dystrophy
It is a rare genetic disorder caused due to mutation of PABN1 gene, characterized by the progressive weakening of ocular and pharyngeal muscles. Unlike other muscular dystrophies, it is more prevalent in the middle ages and above. Affected individuals may have difficulty in speaking, eating, some of the individuals may have weakness of upper and lower limbs, weakness of other facial muscles.
Ocular muscles weaken progressively; limitation of the upward gaze is the earliest symptom. Bilateral ptosis (drooping of the upper eyelids) is one of the most initial signs. During the initial period of the disease, a person may have difficulty in keeping eyelids open at the end of the day, when a person is tired, but as the disease progresses, it becomes a problem from the very start of the day. Slight ophthalmoplegia (weakening of the muscles of the eyes) is also present. Consequently, a person may have difficulty in maintaining the gaze; there may be a slight doubling of vision(5).