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Brody myopathy
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Brody Myopathy

Brody myopathy is a rare genetic condition affecting skeletal muscles, causing cramping and stiffening after exercise due to mutations in the ATP2A1 gene, which delays muscle relaxation.

Overview

Brody myopathy is a condition that affects the skeletal muscles, which are the muscles used for movement. It is a rare condition, although its exact prevalence is unknown.

Symptoms

Affected individuals experience muscle cramping and stiffening after exercise or other strenuous activity, especially in cold temperatures. These symptoms typically begin in childhood. They are usually painless, but in some cases can cause mild discomfort. The muscles usually relax after a few minutes of rest. Most commonly affected are the muscles of the arms, legs, and face (particularly the eyelids).

In some people with Brody myopathy, exercise leads to the breakdown of muscle tissue (rhabdomyolysis). The destruction of muscle tissue releases a protein called myoglobin, which is processed by the kidneys and released in the urine (myoglobinuria). Myoglobin causes the urine to be red or brown.

Causes & Risk Factors

Mutations in the ATP2A1 gene cause Brody myopathy. The ATP2A1 gene provides instructions for making an enzyme called sarco(endo)plasmic reticulum calcium-ATPase 1 (SERCA1). The SERCA1 enzyme is found in skeletal muscle cells, specifically in the membrane of a structure called the sarcoplasmic reticulum. This structure plays a major role in muscle contraction and relaxation by storing and releasing positively charged calcium atoms (calcium ions). When calcium ions are transported out of the sarcoplasmic reticulum, muscles contract; when calcium ions are transported into the sarcoplasmic reticulum, muscles relax. The SERCA1 enzyme transports calcium ions from the cell into the sarcoplasmic reticulum, triggering muscle relaxation.

ATP2A1 gene mutations lead to the production of a SERCA1 enzyme with decreased or no function. As a result, calcium ions are slow to enter the sarcoplasmic reticulum and muscle relaxation is delayed. After exercise or strenuous activity, during which the muscles rapidly contract and relax, people with Brody myopathy develop muscle cramps because their muscles cannot fully relax.

Learn more about the gene associated with Brody myopathy

  • ATP2A1

Inheritance

Brody myopathy is usually inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Some people with autosomal recessive Brody myopathy do not have an identified mutation in the ATP2A1 gene; the cause of the disease in these individuals is unknown.

Other Names for This Condition

  • Brody disease

Frequently Asked Questions

While both conditions cause muscle stiffness after exertion, electromyography (EMG) reveals a critical difference. In myotonia congenita, an EMG records electrical bursts known as myotonic runs or dive-bomber discharges. In contrast, muscles in Brody myopathy remain electrically silent during contracture episodes, proving the stiffness stems from impaired calcium reuptake inside muscle fibers rather than abnormal electrical membrane firing. Genetic testing for ATP2A1 mutations provides definitive confirmation.
Patients should monitor for tea-colored or dark brown urine, severe muscle swelling, profound weakness, and sudden intense muscle pain following strenuous exercise or cold exposure. These symptoms indicate muscle fiber breakdown that releases myoglobin into the bloodstream, posing a high risk for acute kidney injury. Immediate medical attention and intravenous hydration are required if these symptoms appear.
While there is no cure, calcium channel blockers such as verapamil and muscle relaxants like dantrolene have been used off-label to lessen stiffness and cramping. Practically, individuals manage the condition by performing slow, graded warm-ups before physical exertion, avoiding sudden bursts of high-intensity activity, and wearing thermal layers to keep muscles warm, as cold exposure directly exacerbates delayed relaxation.
Because Brody myopathy involves defective calcium transport within skeletal muscle, affected individuals face potential risks with depolarizing neuromuscular blockers such as succinylcholine and certain volatile anesthetics. Patients should alert their surgical and anesthesia teams well in advance so that alternative, non-triggering anesthetic agents are selected to avoid prolonged muscle contractures or hyperthermic complications.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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