Distal myopathy is a group of rare genetic disorders that cause muscle damage and weakness, predominantly in the hands and/or feet. Mutation of many different genes can be causative. Many types involve

dysferlin Dysferlin also known as dystrophy-associated fer-1-like protein is a protein that in humans is encoded by the ''DYSF'' gene. Dysferlin is linked with skeletal muscle repair. A defect in the DYSF gene, located on chromosome 2p12-14, results in sev ...

Signs and symptoms

All of the different types affect different regions of the extremities and can show up as early as 5 years of age to as late as 50 years old. Distal myopathy has slow progress therefore the patient may not know that they have it until they are in their late 40s or 50s. Miyoshi myopathy affects the posterior muscles of the lower leg, more so than the anterior muscles of the lower leg.

Cause

The cause of this myopathy is very hard to determine because it can be a mutation in any of at least eight genes and not all are known yet. These mutations can be inherited from one parent, autosomal dominant, or from both parents, autosomal recessive. There are eight known types of distal myopathy.

Types

Diagnosis

In terms of diagnosis, Vocal cord and pharyngeal distal myopathy should be assessed via serum CK levels, as well as

muscle biopsy In medicine, a muscle biopsy is a procedure in which a piece of muscle tissue is removed from an organism and examined microscopically. A muscle biopsy can lead to the discovery of problems with the nervous system, connective tissue, vascular sys ...

of the individual suspected of being afflicted with this condition

Management

As of 2011, no disease modifying treatments are known. Foot drop can be managed with ankle-foot orthoses or surgical

tendon transfer A tendon transfer is a surgical process in which the insertion of a tendon is moved, but the origin remains in the same location. Tendon transfer involves redistribution of muscle power, not recreation. Tendons are transferred at the distal atta ...

, in which the

tibialis posterior muscle The tibialis posterior muscle is the most central of all the leg muscles, and is located in the deep posterior compartment of the leg. It is the key stabilizing muscle of the lower leg. Structure The tibialis posterior muscle originates on the i ...

is repurposed to function as a

tibialis anterior muscle The tibialis anterior muscle is a muscle in humans that originates along the upper two-thirds of the lateral (outside) surface of the tibia and inserts into the medial cuneiform and first metatarsal bones of the foot. It acts to dorsiflex and inve ...

. In select types of distal myopathy, evaluation of the heart may be indicated. Scoliosis and contractures can be surgically managed.

References

External links

{{musculoskeletal-disease-stub Muscular dystrophy