Tibial muscular dystrophy
| Tibial muscular dystrophy | |
|---|---|
| Other names | Udd (Distal) Myopathy, Tardive tibial muscular dystrophy, Udd-Markesbery muscular dystrophy |
| Selected MR images from different patients with TMD. Tibialis anterior (TA) is early involved, even in patients with minimal fat replacement (A). Generally tibialis anterior is severely involved (B–D). Extensor digitorum longus (EDL) is assymetrically involved. Some patients have assymetric and non-homogeneous involvement of soleus (SOL) and gastrocnemius (GM). Axial images from pelvis and thigh of four different patients. Notice the asymmetry and very selective involvement of some muscles. The involvement of gluteus minimus (Gmin) that could be mild (G) / severe (E). Gluteus medium (GMed) could also be involved (E). Semimembranosus (SM), semitendinosus (ST) and biceps femoris (BFSH-short head and BFLH—long head) are the other most commonly involved muscle outside the leg. Some patients may have severe atrophy of rectus femoris (RF). | |
| Specialty | Neurology |
| Symptoms | Weakness and atrophy of tibialis anterior, extensor digitorum longus, extensor hallucis longus |
| Usual onset | 35-55 years |
| Prognosis | Patients usually remain ambulant, although some of them need mobility aids |
Tibial muscular dystrophy (TMD) (also known as Udd myopathy) is a rare hereditary disorder, which is caused by a mutation in a gene TTN. TMD usually begins at the age of 35-55 years and the disease progresses slowly. The disorder causes weakness and atrophy of tibialis anterior, extensor digitorum longus, extensor hallucis longus. TMD is an autosomal dominant condition.
TMD is most common in Finland, which is estimated to be 15:100,000 individuals due to founder effect.