What is Nemaline Myopathy?

Nemaline myopathy is a rare genetic disease involving the skeletal muscles. People with this condition have muscle weakness of varying severity that can lead to difficulty walking, breathing, eating, and speaking. Like many other genetic disorders, nemaline myopathy cannot be cured, but there are treatment options available to help people manage this disease. At least six different forms are recognized and it is important to be aware that even the same form can present differently in different patients.

A number of different genes are involved in nemaline myopathy. The hallmark finding of this condition is a scattering of small structures that look like rods inside the skeletal muscles. This condition is also known as rod myopathy in a reference to these structures. The condition was first identified in the 1950s and named in the 1960s. Initially, researchers thought the rods were artifacts on the biopsy samples, and dismissed the original description of this disease.

Nemaline myopathy is usually not progressive, and the patient should not grow weaker over the course of a lifetime. Some people are born with muscle weakness and have a distinctive floppy appearance as babies. In the adult onset form, people live healthy childhoods and develop muscle weakness as adults. Depending on the severity of the muscle weakness, nemaline myopathy may be a relatively mild condition, or it may create muscle weakness that leads to the need for mobility aids and other assistive devices. Some patients develop a spinal curvature because their spines do not receive enough support.

One of the biggest concerns with nemaline myopathy is that some patients find it difficult to breathe because of their weakened muscles. Some patients may require ventilator support and respiratory therapy to breathe comfortably and in young children, difficulty breathing is an especially important concern. Babies born with nemaline myopathy are monitored closely for signs of respiratory distress so that interventions can be provided as quickly as possible.

Another issue experienced by some patients is difficulty swallowing due to weakness in the facial and throat muscles. Some patients cannot take food by mouth and rely on a feeding tube for nutrition. For people with facial and throat muscle weakness, spoken communication can be challenging. It may be necessary to use sign language or a communication board to be understood. A speech-language pathologist can work with a patient to provide an assessment and treatment plan if the patient experiences these common difficulties.