Distal myopathy explained

Distal myopathy
Synonyms:Distal muscular dystrophy
Field:Neurology, neuromuscular medicine
Symptoms:Weakness of hands and/or feet
Complications:Cardiomyopathy
Onset:Variable
Duration:Lifetime
Types:Classic, myofibrillar myopathy, other
Causes:Genetic mutation of various genes
Diagnosis:Genetic testing, muscle biopsy
Frequency:Rare

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.[1]

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.[2] [3]

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

Classic distal muscular dystrophies
TypeEponymInheritanceOMIMGeneLocusGene also implicated in:
Late adult-onset type 1WelanderADTIA1[4] 2p13[5]
Late adult-onset type 2a[6] - Finnish (tibial)UddADTTN2q31.2
Late adult-onset type 2bMarkesbery–GriggsADZASP10q23.2
Early adult-onset type 1[7] NonakaARGNE9p13.3
style='border-style: solid solid dashed solid;' Early adult-onset type 2style='border-style: none solid dashed solid;' MiyoshiARDYSF2p13.3-p13.1style='border-style: solid solid dashed solid;' limb-girdle muscular dystrophy type 2B.[8]
style='border-style: none solid solid solid;' Distal myopathy with anterior tibial onset (DMAT)[9] [10] style='border-style: none solid solid solid;' style='border-style: none solid solid solid;' DMAT can be considered a variant of Miyoshi.
Early adult-onset type 3Laing (Gower)ADMYH714q11.2
AD = autosomal dominant; AR = autosomal recessive
Myofibrillar myopathies classifiable as distal myopathy
TypeEponymInheritanceOMIMGeneLocusGene also implicated in:
Desmin — adult onset (MFM1)Hereditary inclusion-body myositis type 1AD
αB-crystallin — early - mid adult (MFM2)AD
ZASP— late adult (MFM4)AD
ScapuloperonealAD
MFM = myofibrillary myopathy; AD = autosomal dominant; AR = autosomal recessive

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[12]

Management

As of 2011, no disease modifying treatments are known.[13] Foot drop can be managed with ankle-foot orthoses or surgical tendon transfer, in which the tibialis posterior muscle is repurposed to function as a tibialis anterior muscle. In select types of distal myopathy, evaluation of the heart may be indicated. Scoliosis and contractures can be surgically managed. In 2024 a drug to treat distal myopathy was approved in Japan.[14]

Further reading

Notes and References

  1. Murakami N, Sakuta R, Takahashi E, etal . Early onset distal muscular dystrophy with normal dysferlin expression . Brain Dev. . 27 . 8 . 589–91 . December 2005 . 16310593 . 10.1016/j.braindev.2005.02.002 . 28957231 .
  2. Soares CN, de Freitas MR, Nascimento OJ, da Silva LF, de Freitas AR, Werneck LC . Myopathy of distal lower limbs: the clinical variant of Miyoshi . Arq Neuropsiquiatr . 61 . 4 . 946–9 . December 2003 . 14762596 . 10.1590/S0004-282X2003000600011. free .
  3. Aoki. Masashi. Dysferlinopathy. GeneReviews. 1 January 1993. 20301480. 10 May 2016.
  4. Hackman P, Sarparanta J, Lehtinen S, Vihola A, Evilä A, Jonson PH, Luque H, Kere J, Screen M, Chinnery PF, Åhlberg G, Edsröm L, Udd B . Welander Distal Myopathy Is Caused by a Mutation in the RNA-Binding Protein TIA1. Annals of Neurology . 73 . 4 . 500–509 . January 2013 . 23401021 . 10.1002/ana.23831. 13908127 .
  5. von Tell D, Bruder CE, Anderson LV, Anvret M, Ahlberg G . Refined mapping of the Welander distal myopathy region on chromosome 2p13 positions the new candidate region telomeric of the DYSF locus . Neurogenetics . 4 . 4 . 173–7 . August 2003 . 12836053 . 10.1007/s10048-003-0154-z. 27539044 .
  6. Dimachkie . MM . Barohn . RJ . Distal myopathies. . Neurologic Clinics . August 2014 . 32 . 3 . 817-42, x . 10.1016/j.ncl.2014.04.004 . 25037092. 4109660 .
  7. Saperstein . DS . Amato . AA . Barohn . RJ . Clinical and genetic aspects of distal myopathies. . Muscle & Nerve . November 2001 . 24 . 11 . 1440–50 . 10.1002/mus.1167 . 11745945. 26573674 .
  8. Illa I . Distal myopathies . J. Neurol. . 247 . 3 . 169–74 . March 2000 . 10787109 . 10.1007/s004150050557 . 39723106 . https://archive.today/20130213012235/http://link.springer.de/link/service/journals/00415/bibs/0247003/02470169.htm . dead . 2013-02-13 .
  9. Liu . J . Aoki . M . Illa . I . Wu . C . Fardeau . M . Angelini . C . Serrano . C . Urtizberea . JA . Hentati . F . Hamida . MB . Bohlega . S . Culper . EJ . Amato . AA . Bossie . K . Oeltjen . J . Bejaoui . K . McKenna-Yasek . D . Hosler . BA . Schurr . E . Arahata . K . de Jong . PJ . Brown RH . Jr . Dysferlin, a novel skeletal muscle gene, is mutated in Miyoshi myopathy and limb girdle muscular dystrophy. . Nature Genetics . September 1998 . 20 . 1 . 31–6 . 10.1038/1682 . 9731526. 12018395 .
  10. Illa . I . Serrano-Munuera . C . Gallardo . E . Lasa . A . Rojas-García . R . Palmer . J . Gallano . P . Baiget . M . Matsuda . C . Brown . RH . Distal anterior compartment myopathy: a dysferlin mutation causing a new muscular dystrophy phenotype. . Annals of Neurology . January 2001 . 49 . 1 . 130–4 . 10.1002/1531-8249(200101)49:1<130::AID-ANA22>3.0.CO;2-0 . 11198284.
  11. Johnson . JO . Pioro . EP . Boehringer . A . Chia . R . Feit . H . Renton . AE . Pliner . HA . Abramzon . Y . Marangi . G . Winborn . BJ . Gibbs . JR . Nalls . MA . Morgan . S . Shoai . M . Hardy . J . Pittman . A . Orrell . RW . Malaspina . A . Sidle . KC . Fratta . P . Harms . MB . Baloh . RH . Pestronk . A . Weihl . CC . Rogaeva . E . Zinman . L . Drory . VE . Borghero . G . Mora . G . Calvo . A . Rothstein . JD . ITALSGEN. . Drepper . C . Sendtner . M . Singleton . AB . Taylor . JP . Cookson . MR . Restagno . G . Sabatelli . M . Bowser . R . Chiò . A . Traynor . BJ . Mutations in the Matrin 3 gene cause familial amyotrophic lateral sclerosis. . Nature Neuroscience . May 2014 . 17 . 5 . 664–666 . 10.1038/nn.3688 . 24686783. 4000579 .
  12. Book: Distal muscular dystrophies . Handbook of Clinical Neurology . 1 January 2011 . 101 . 239–262 . 10.1016/B978-0-08-045031-5.00016-5 . 21496636 . en . 0072-9752. Udd . Bjarne . Muscular Dystrophies . 9780080450315 .
  13. Book: Udd . B . Distal muscular dystrophies . Muscular Dystrophies . Handbook of Clinical Neurology . 2011 . 101 . 239–62 . 10.1016/B978-0-08-045031-5.00016-5 . 21496636. 9780080450315 .
  14. News: Persistence pays off with approval of distal myopathy drug . The Japan Times . 20 May 2024.

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