Protein that causes muscle weakness identified: Know the reasons behind this condition

Protein that causes muscle weakness identified: Know the reasons behind this condition
Muscle weakness can be caused by a variety of conditions including metabolic diseases, neurologic diseases, muscle diseases and even poisoning. © Shutterstock

Scientists have identified a protein that may cause muscle weakness as you age. But this can happen also due to a sedentary lifestyle or certain health conditions. Read on to know more.

Written by Editorial Team |Updated : August 9, 2019 5:02 PM IST

When you don't use your muscles, it becomes weak. A sedentary lifestyle is actually one of the most common causes of muscle weakness. But ageing can also cause your muscles to lose strength and bulk and become weaker. Muscles power is maximum when we are in our 20s to 30s.

As we age, we experience ageing symptoms accompanied by muscle loss. In a new study, researchers at the Max Delbrueck Center for Molecular Medicine (MDC) have identified a protein that has a major influence on healthy ageing by supporting muscle strength and lifespan. They found that animals lacking the protein LIN-53 have severe muscle defects and limited mobility. LIN-53 deficiency can cause premature death.

LIN-53 binds to molecules called histones that are wrapped tightly inside long DNA strands within the cell nucleus. Histone modifications can turn gene expression levels up or down, ultimately affecting the development, function and lifespan of an organism.

Because of its interaction with histones, LIN-53 is considered an 'epigenetic factor', which can influence the activation and deactivation of gene expression without changing the underlying DNA sequence. LIN-53 affected muscle development through the molecular complex NuRD, yet affected lifespan through a separate complex, Sin3. According to the experts, the fact that these distinct pathways both involve LIN-53 strongly indicates that the protein is a link between health-span and lifespan. The journal Aging Cell published this study.


Muscle weakness can be mild or severe, temporary or permanent, reversible or irreversible. It is be caused by a variety of conditions including metabolic diseases, neurologic diseases, muscle diseases and even poisoning.

Addison's disease

It is a disorder that occurs when the adrenal glands located at the top of the kidneys do not produce enough hormones. The adrenal glands are made up of the outer portion called cortex and the inner portion medulla. Addison's disease is the damage to the adrenal cortex. The damage can be caused by autoimmune diseases, infections like HIV, tuberculosis or fungal infections, haemorrhage, tumours and blood thinning drugs.


When the parathyroid glands produce too much parathyroid hormone (PTH), the disorder is termed hyperparathyroidism. Parathyroid glands, located in the neck behind the thyroid glands, regulate calcium, phosphorus, and vitamin D levels in the body.


It is a common disorder in women. It is due to overactive thyroid glands symptoms with infection or stress. Other symptoms may include fever, abdominal pain and decreased alertness. Thyrotoxicosis can also occur because of Grave's disease (autoimmune hyperthyroidism).

Guillain-Barre syndrome

GBS is an autoimmune disorder in which the body's immune system attacks a part of the nervous system, especially the nerve covering called myelin sheath. This leads to nerve inflammation that causes muscle weakness and paralysis.

Bells' palsy

This is a disorder which affects the nerve which controls movement of muscles in the face. Damage to this nerve causes muscle weakness or paralysis in the face.

Amyotrophic lateral sclerosis (ALS)

This is also called Lou Gehrig's disease. ALS affects the nerve cells in the brain and spinal cord that control voluntary muscle movement. Generally, the symptoms such as difficulty breathing and swallowing, slurred speech, drooling, along with muscle cramps and muscle weakness appear after the age of 50 but it may also appear earlier in some. Muscle weakness gets worse slowly over time. First it affects one part of the body (arm or hand) that eventually leads to difficulty in climbing stairs, walking, and lifting objects.

Multiple sclerosis

MS is a chronic debilitating disorder in which the body's immune system eats away at the myelin sheath (nerve cover). It is similar to GBS but the only difference is GBS affects the peripheral nerves whereas MS affects the central nervous system. Symptoms of MS include muscle weakness, numbness in one or more parts of the body, fatigue, dizziness, and slurred speech, loss of vision in one eye or double vision or blurry vision.


A stroke can happen when blood flow to the brain is interrupted by a clot (ischemic stroke) or if there us a ruptured blood vessel (haemorrhagic stroke). This causes lack of oxygen in the brain and the brain cells die suddenly. The symptoms can be inability to speak, loss of balance and coordination, memory loss, numbness, muscle weakness, or paralysis on one side of the body.

McArdle' disease

People born with this type of metabolic muscle disorder are unable to produce an enzyme called muscle phosphorylase that helps produce the energy required by the skeletal muscles for exercise. Another name for this disease is Glycogen Storage Disease Type V (GSD V).


Myositis or muscle inflammation involve a group of muscle diseases such as dermatomyositis which is a muscle inflammation with patchy, dusky and red or purple skin rashes, polymyositis, more common in women than in men, in which muscle weakness happens over days, weeks or months and begins in the neck, hip, back, and shoulder muscles, inclusion-body myositis, mostly occurring in men, in which the muscle weakness and shrinking is first observed in the thigh muscles, forearm muscles and muscles below the knee, juvenile myositis occurring in children under the age of 18 and skin rash as the first symptom.

Muscular dystrophy

It is a group of inherited disorders that involve muscle weakness that gets worse over time with subsequent muscle loss. Common muscle dystrophies include Becker muscular dystrophy, a slowly progressing condition that affects only male and causes weakness and wastage of muscles, Duchenne muscular dystrophy, a progressive neuromuscular condition caused by a lack of a protein called dystrophin and Myotonic dystrophy, a condition that involves weakness and slowly progressive wasting of voluntary muscles in the face, neck, and lower arms and legs.


It is a type of poisoning caused by Clostridium botulinum bacteria. This bacteria thrives in improperly canned or processed foods or they may enter the body through wounds. Symptoms include muscle weakness and paralysis on both sides of the body and abdominal cramps in adults. In infants, it is constipation, difficulty swallowing and speaking, nausea and vomiting.

Myasthenia gravis

It is an autoimmune disorder. The body produces antibodies that block the voluntary muscle cells from receiving messages from nerve cells. This causes muscle weakness and excessive fatigue.


Pernicious anaemia is a condition in which the body can't make enough red blood cells. This is because it does not have enough vitamin B12. Vitamin B12 deficiency causes nerve damage. This then causes tingling sensation in hands and feet, muscle weakness, and loss of reflexes.

Post-polio syndrome

It is a condition that affects polio survivors. The symptoms include weakening in the muscles previously affected by polio infection, fatigue and gradual decrease in the size of the muscles. Although it is rarely life threatening, it negatively affects the quality of life as the affected person is unable to function independently.