9d58

Structural highlights

Disease

DMD_HUMAN Defects in DMD are the cause of Duchenne muscular dystrophy (DMD) [MIM:310200. DMD is the most common form of muscular dystrophy; a sex-linked recessive disorder. It typically presents in boys aged 3 to 7 year as proximal muscle weakness causing waddling gait, toe-walking, lordosis, frequent falls, and difficulty in standing up and climbing up stairs. The pelvic girdle is affected first, then the shoulder girdle. Progression is steady and most patients are confined to a wheelchair by age of 10 or 12. Flexion contractures and scoliosis ultimately occur. About 50% of patients have a lower IQ than their genetic expectations would suggest. There is no treatment.^{[1] [2] [3] [4]} Defects in DMD are the cause of Becker muscular dystrophy (BMD) [MIM:300376. BMD resembles DMD in hereditary and clinical features but is later in onset and more benign.^[5] Defects in DMD are a cause of cardiomyopathy dilated X-linked type 3B (CMD3B) [MIM:302045; also known as X-linked dilated cardiomyopathy (XLCM). Dilated cardiomyopathy is a disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.^{[6] [7] [8]}

Function

DMD_HUMAN Anchors the extracellular matrix to the cytoskeleton via F-actin. Ligand for dystroglycan. Component of the dystrophin-associated glycoprotein complex which accumulates at the neuromuscular junction (NMJ) and at a variety of synapses in the peripheral and central nervous systems and has a structural function in stabilizing the sarcolemma. Also implicated in signaling events and synaptic transmission.^[9]

References

1. ↑ Prior TW, Papp AC, Snyder PJ, Burghes AH, Bartolo C, Sedra MS, Western LM, Mendell JR. A missense mutation in the dystrophin gene in a Duchenne muscular dystrophy patient. Nat Genet. 1993 Aug;4(4):357-60. PMID:8401582 doi:http://dx.doi.org/10.1038/ng0893-357
2. ↑ Prior TW, Bartolo C, Papp AC, Snyder PJ, Sedra MS, Burghes AH, Mendell JR. Identification of a missense mutation, single base deletion and a polymorphism in the dystrophin exon 16. Hum Mol Genet. 1994 Jul;3(7):1173-4. PMID:7981690
3. ↑ Lenk U, Oexle K, Voit T, Ancker U, Hellner KA, Speer A, Hubner C. A cysteine 3340 substitution in the dystroglycan-binding domain of dystrophin associated with Duchenne muscular dystrophy, mental retardation and absence of the ERG b-wave. Hum Mol Genet. 1996 Jul;5(7):973-5. PMID:8817332
4. ↑ Goldberg LR, Hausmanowa-Petrusewicz I, Fidzianska A, Duggan DJ, Steinberg LS, Hoffman EP. A dystrophin missense mutation showing persistence of dystrophin and dystrophin-associated proteins yet a severe phenotype. Ann Neurol. 1998 Dec;44(6):971-6. PMID:9851445 doi:10.1002/ana.410440619
5. ↑ Eraslan S, Kayserili H, Apak MY, Kirdar B. Identification of point mutations in Turkish DMD/BMD families using multiplex-single stranded conformation analysis (SSCA). Eur J Hum Genet. 1999 Oct-Nov;7(7):765-70. PMID:10573008 doi:10.1038/sj.ejhg.5200370
6. ↑ Ortiz-Lopez R, Li H, Su J, Goytia V, Towbin JA. Evidence for a dystrophin missense mutation as a cause of X-linked dilated cardiomyopathy. Circulation. 1997 May 20;95(10):2434-40. PMID:9170407
7. ↑ Feng J, Yan JY, Buzin CH, Sommer SS, Towbin JA. Comprehensive mutation scanning of the dystrophin gene in patients with nonsyndromic X-linked dilated cardiomyopathy. J Am Coll Cardiol. 2002 Sep 18;40(6):1120-4. PMID:12354438
8. ↑ Feng J, Yan J, Buzin CH, Towbin JA, Sommer SS. Mutations in the dystrophin gene are associated with sporadic dilated cardiomyopathy. Mol Genet Metab. 2002 Sep-Oct;77(1-2):119-26. PMID:12359139
9. ↑ Haenggi T, Fritschy JM. Role of dystrophin and utrophin for assembly and function of the dystrophin glycoprotein complex in non-muscle tissue. Cell Mol Life Sci. 2006 Jul;63(14):1614-31. PMID:16710609 doi:10.1007/s00018-005-5461-0
10. ↑ Streeter O, Shi K, Vavra J, Aihara H, Ervasti JM, Evans R 3rd, Muretta JM. Human dystrophin tandem calponin homology actin-binding domain crystallized in a closed-state conformation. Acta Crystallogr D Struct Biol. 2025 Mar 1;81(Pt 3):122-129. PMID:40007458 doi:10.1107/S2059798325001457