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PubMed This is a summary of 57 peer-reviewed journal articles Updated
Neurology · Limb-Girdle Muscular Dystrophy R1

Understanding LGMDR1 (Calpainopathy)

At a Glance

LGMDR1, also known as calpainopathy or LGMD2A, is a rare genetic disorder causing slowly progressive weakness in the shoulder and pelvic muscles. It typically spares the heart and brain. Management focuses on physical therapy and respiratory monitoring to maintain mobility and quality of life.

A diagnosis of LGMDR1 (also known as calpainopathy) can feel overwhelming, but understanding the nature of this condition is the first step toward managing it effectively. This condition is a subtype of limb-girdle muscular dystrophy (LGMD), a group of rare genetic disorders that primarily cause weakness and wasting in the muscles of the pelvic and shoulder girdles [1][2].

The Naming Update: From LGMD2A to LGMDR1

You may see your condition referred to by several names. Historically, it was called LGMD2A. In 2018, the naming system was updated to be more descriptive and standardized [3].

  • The “R” in LGMDR1 stands for recessive, meaning a person typically inherits two altered copies of the gene (one from each parent) [3].
  • The “1” indicates it was the first recessive limb-girdle dystrophy to be genetically identified [4].
  • It is also commonly called calpainopathy because it is caused by a deficiency in a protein called calpain-3, which is produced by the CAPN3 gene [4][5].

Understanding Your Condition

LGMDR1 is considered one of the most common forms of limb-girdle muscular dystrophy worldwide, yet it is still classified as a rare disease [1][6]. It primarily affects the skeletal muscles—the muscles you use for movement—while typically sparing other major organs [7].

Three Stabilizing Facts

  1. Sparing of the Heart and Mind: Unlike some other forms of muscular dystrophy, LGMDR1 rarely affects the heart muscle (cardiac dysfunction is infrequent) [8][9]. Additionally, the condition does not typically impact cognitive function or intelligence [7].
  2. Slow Progression: While LGMDR1 is a progressive condition, the decline in muscle strength usually occurs slowly over many years or decades [10][11]. This allows many patients a long window of time to adapt and utilize supportive therapies.
  3. Variable Onset: The age at which symptoms first appear varies greatly. While many experience “classic” onset in their teens or early twenties, some individuals are not diagnosed until much later in life, sometimes as late as their 60s [12][13].

Managing the Path Ahead

There is currently no cure for LGMDR1, but management focuses on maintaining function and preventing complications through supportive care [14][15].

  • Physical Therapy: Supervised, gentle exercise and stretching can help manage joint tightness (contractures) and maintain mobility [16][10].
  • Respiratory Monitoring: While the heart is usually spared, the muscles used for breathing can weaken over time. Regular monitoring of respiratory function is a standard part of care, especially as the disease progresses [8][11].
  • Family Planning: Understanding your specific CAPN3 mutation can help clarify the inheritance pattern. For the recessive form (LGMDR1), unless your partner is also a carrier of a CAPN3 mutation or has the disease, your children will only be “carriers” of one mutated gene and will not develop symptoms [17][18].

Research is actively evolving, with scientists investigating new strategies such as gene therapy and pharmacological treatments to target the underlying cause of calpain-3 deficiency [19][20].

To learn more, explore the pages in this guide:

01

Symptoms and Disease Progression

Learn about LGMDR1 (calpainopathy) symptoms and disease progression. Understand early signs like joint contractures, muscle weakness patterns, and timelines.

02

The Science of Calpain-3 and Getting a Clear Diagnosis

Learn about the science of Calpain-3 and LGMDR1. Understand CAPN3 mutations, why misdiagnosis with inflammatory myopathy is common, and genetic testing.

03

The Path to a Diagnosis: Tests and Reports

Learn how LGMDR1 (calpainopathy) is diagnosed. Understand your test reports, including CAPN3 genetic testing, muscle MRIs, CK levels, and biopsies.

04

Treatment Options and the Research Horizon

Explore treatment options for LGMDR1 (calpainopathy). Learn about supportive care, physical therapy guidelines, and the latest gene therapy research.

05

Building Your Care Team and Long-Term Monitoring

Learn how to build your LGMDR1 care team and manage long-term monitoring. Understand respiratory tests, mobility aids, and critical anesthesia precautions.

Common questions in this guide

What is the difference between LGMDR1 and LGMD2A?
There is no difference. LGMD2A is the historical name for the condition. In 2018, the medical naming system was updated to LGMDR1 to specify that it is an inherited recessive disorder caused by a specific genetic mutation.
Will LGMDR1 (calpainopathy) affect my heart or brain?
No, LGMDR1 typically spares the heart muscle and does not impact cognitive function or intelligence. It primarily affects the skeletal muscles you use for everyday movement.
How fast does LGMDR1 usually progress?
LGMDR1 is generally a slowly progressive condition. The decline in muscle strength usually occurs gradually over many years or even decades, which allows patients time to adapt and use supportive therapies.
Can physical therapy help with my LGMDR1 symptoms?
Yes, supervised, gentle exercise and stretching are key components of managing LGMDR1. Physical therapy helps maintain mobility and prevents severe joint tightness, known as contractures.
Will my children inherit LGMDR1 from me?
Because LGMDR1 is a recessive genetic condition, both parents must carry a mutation for a child to develop symptoms. If your partner does not carry a CAPN3 mutation, your children will be carriers but will not develop the disease.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is my specific genetic mutation in the CAPN3 gene, and is it inherited in a recessive (LGMDR1) or dominant (LGMDD4) pattern?
  2. 2.Can you refer me to a physical therapist who has experience with calpainopathy or limb-girdle muscular dystrophies?
  3. 3.How often should we monitor my respiratory function, and what baseline tests do I need now?
  4. 4.Are there local or national patient registries for LGMDR1 that I should join to stay informed about clinical trials?
  5. 5.Based on my current muscle strength, what types of exercise are safe and most beneficial for me right now?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (20)
  1. 1

    Calpainopathy (Leyden-Mobius Limb-Girdle Muscular Dystrophy Type 2A Phenotype) and Dysferlinopathy (Miyoshi Distal Myopathy Limb-Girdle Muscular Dystrophy Type 2B Phenotype) of Preadolescent Onset: Case Reports of Two Male Filipinos.

    Quilacio JMS, Rosales RL, Ampil ER

    Cureus 2022; (14(1)):e21353 doi:10.7759/cureus.21353.

    PMID: 35198268
  2. 2

    Natural history of LGMD2A for delineating outcome measures in clinical trials.

    Richard I, Hogrel JY, Stockholm D, et al.

    Annals of clinical and translational neurology 2016; (3(4)):248-65 doi:10.1002/acn3.287.

    PMID: 27081656
  3. 3

    229th ENMC international workshop: Limb girdle muscular dystrophies - Nomenclature and reformed classification Naarden, the Netherlands, 17-19 March 2017.

    Straub V, Murphy A, Udd B,

    Neuromuscular disorders : NMD 2018; (28(8)):702-710 doi:10.1016/j.nmd.2018.05.007.

    PMID: 30055862
  4. 4

    Disease Progression and Mutation Pattern in a Large Cohort of LGMD R1/LGMD 2A Patients from India.

    Ganaraja VH, Polavarapu K, Bardhan M, et al.

    Global medical genetics 2022; (9(1)):34-41 doi:10.1055/s-0041-1736567.

    PMID: 35169782
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    Mutational Spectrum of CAPN3 with Genotype-Phenotype Correlations in Limb Girdle Muscular Dystrophy Type 2A/R1 (LGMD2A/LGMDR1) Patients in India.

    Pathak P, Sharma MC, Jha P, et al.

    Journal of neuromuscular diseases 2021; (8(1)):125-136 doi:10.3233/JND-200547.

    PMID: 33337384
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    Expert panel curation of 31 genes in relation to limb girdle muscular dystrophy.

    Mohan S, McNulty S, Thaxton C, et al.

    Annals of clinical and translational neurology 2024; (11(9)):2268-2276 doi:10.1002/acn3.52127.

    PMID: 39215466
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    Limb Girdle Muscular Dystrophies.

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    Neurologic clinics 2020; (38(3)):493-504 doi:10.1016/j.ncl.2020.03.009.

    PMID: 32703463
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    Cardiopulmonary dysfunction in patients with limb-girdle muscular dystrophy 2A.

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    Muscle & nerve 2017; (55(4)):465-469 doi:10.1002/mus.25369.

    PMID: 27500519
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    Evaluation of heart involvement in calpainopathy (LGMD2A) using cardiovascular magnetic resonance.

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    Muscle & nerve 2015; (52(4)):661-3 doi:10.1002/mus.24717.

    PMID: 26032656
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    Fatty infiltration evaluation and selective pattern characterization of lower limbs in limb-girdle muscular dystrophy type 2A by muscle magnetic resonance imaging.

    Feng X, Luo S, Li J, et al.

    Muscle & nerve 2018; (58(4)):536-541 doi:10.1002/mus.26169.

    PMID: 29797799
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    Over three decades of natural history of limb girdle muscular dystrophy type R1/2A and R2/2B: Mathematical modelling of a multifactorial study.

    LoMauro A, Gandossini S, Russo A, et al.

    Neuromuscular disorders : NMD 2021; (31(6)):489-497 doi:10.1016/j.nmd.2021.02.018.

    PMID: 33836912
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    A rare case of late-onset limb-girdle muscular dystrophy: Calpainopathy.

    Painkra B, Mallick R, Das S, et al.

    Aging medicine (Milton (N.S.W)) 2022; (5(3)):237-240 doi:10.1002/agm2.12219.

    PMID: 36247336
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    Limb-girdle muscular dystrophy type 2A in Brazilian children.

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    Arquivos de neuro-psiquiatria 2015; (73(12)):993-7.

    PMID: 26677118
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    Current and Future Therapeutic Strategies for Limb Girdle Muscular Dystrophy Type R1: Clinical and Experimental Approaches.

    Şahin İO, Özkul Y, Dündar M

    Pathophysiology : the official journal of the International Society for Pathophysiology 2021; (28(2)):238-249 doi:10.3390/pathophysiology28020016.

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    Calpainopathy (limb-girdle muscular dystrophy type R1): clinical features, diagnostic approaches, and biotechnological treatment methods.

    Bardakov SN, Sorochanu I, Mkrtchyan LA, et al.

    Journal of neuromuscular diseases 2025; (12(5)):594-618 doi:10.1177/22143602251345967.

    PMID: 40452441
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    Muscle exercise in limb girdle muscular dystrophies: pitfall and advantages.

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    Allosteric Modulation of GSK-3β as a New Therapeutic Approach in Limb Girdle Muscular Dystrophy R1 Calpain 3-Related.

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This page provides an educational overview of LGMDR1 (calpainopathy). It is not a substitute for professional medical advice, diagnosis, or treatment from your neurologist or genetic counselor.

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