Oculopharyngeal Spinal Muscular Atrophy (OPSMA), also known as Oculopharyngeal Muscular Dystrophy (OPMD), is a rare inherited neuromuscular disorder characterized by progressive weakening of the muscles involved in eye movement (oculo-), swallowing (pharyngeal), and voluntary muscle control (spinal muscular atrophy).
OPSMA is caused by a genetic mutation resulting in the abnormal expansion of a specific DNA sequence in the PABPN1 gene, which prevents the production of normal PABPN1 protein. This leads to the buildup of protein clumps within the muscle cells, impairing their normal function.
Symptoms manifest most commonly in middle-aged individuals, typically in their 40s or 50s, but can also affect younger or older individuals. Individuals with OPSMA may experience drooping eyelids (ptosis), difficulty in moving their eyes freely (ophthalmoplegia), and weakness or wasting of the muscles involved in swallowing (dysphagia). In some cases, it can also affect facial muscles, causing difficulty in facial expressions and speaking.
As the disease progresses, muscle weakness may extend to other parts of the body, leading to general muscular weakness and atrophy, particularly in the shoulders, upper arms, and pelvic region. This can cause challenges in performing activities of daily living and increase the risk of falls.
While there is currently no cure for OPSMA, symptomatic treatments can help manage specific manifestations such as eyelid surgery for ptosis or dietary modifications and swallowing techniques for dysphagia. Physical and occupational therapy may also be beneficial for maintaining muscle strength and mobility. Researchers continue to investigate potential therapeutic options for the future.
