Distal Muscular Dystrophy
Distal muscular dystrophy is a group of disorders characterized by onset in the hands or feet. Many types involve dysferlin, but it has been suggested that not all cases do.
Types
| Name | OMIM | Locus |
|---|---|---|
| Miyoshi myopathy (in Japan) | 254130 | DYSF at 2p13.3-p13.1(DYSF is also associated with limb-girdle muscular dystrophy type 2B.) |
| Distal myopathy with anterior tibial onset | 606768 | DYSF at 2p13.3-p13.1 |
| Welander distal myopathy | 604454 | TIA1 at 2p13 |
Cause
The cause of this dystrophy 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. Along with being able to inherit the mutated gene, distal muscular dystrophy has slow progress therefore the patient may not know that they have it until they are in their late 40s or 50s. There are eight known types of distal muscular dystrophy. They are Welander’s distal myopathy, Finnish (tibial) distal myopathy, Miyoshi distal myopathy, Nonaka distal myopathy, Gowers–Laing distal myopathy, Hereditary inclusion-body myositis type 1, Distal myopathy with vocal cord and pharyngeal weakness, and ZASP-related myopathy. All of these affect different regions of the extremities and can show up as early as 5 years of age to as late as 50 years old.
Diagnosis
In terms of diagnosis, Vocal cord and pharyngeal distal myopathy should be assessed via serum CK levels, as well as muscle biopsy of the individual suspected of being afflicted with this condition