概述
Amyloid light-chain (AL) amyloidosis is a rare and serious condition in which a substance called amyloid builds up in the body. The amyloid forms when certain proteins fold the wrong way and stick together. Those proteins are called light chains.
Other names for AL amyloidosis are:
- Immunoglobulin light chain amyloidosis.
- Primary amyloidosis.
- Systemic AL amyloidosis.
As amyloid builds up in the body, it can cause life-threatening organ damage. AL amyloidosis may affect the heart, kidneys, nervous system, liver, digestive tract and other parts of the body. If the condition affects the heart, it can lead to heart failure.
AL amyloidosis sometimes happens with a cancer of the bone marrow called multiple myeloma. However, most people with AL amyloidosis do not have multiple myeloma.
AL amyloidosis symptoms depend on the parts of the body affected. The symptoms may seem like those of common conditions. For example, you might feel very tired or be short of breath. Letting your care team know when you don't feel well may help find AL amyloidosis earlier. Newer medicines can slow the disease and are helping people live longer. Some people also may need a blood stem cell transplant, although that's now becoming less common.
Types
There are different types of amyloidosis. The type of amyloidosis is based on the protein that forms the amyloid deposits. This article focuses on AL amyloidosis.
Other types of amyloidosis include:
- Amyloid transthyretin (ATTR) amyloidosis.
- Amyloid A amyloidosis, also called AA amyloidosis.
- Other, rarer types, including apolipoprotein A-I (AApoAI) and apolipoprotein A-II (AApoAII).
Amyloidosis also may be grouped by how much of the body it affects.
- If the condition affects more than one part of the body, it's called systemic amyloidosis.
- If the condition only affects one part of the body, it's called localized amyloidosis.
If amyloidosis affects the heart, it's called cardiac amyloidosis.
症状
Symptoms of AL amyloidosis happen as amyloid builds up in the body. They vary depending on which organs are affected. The symptoms may look like those of other conditions.
AL amyloidosis symptoms often affect more than one part of the body. That means it's a systemic condition. Common symptoms may include:
- Feeling very tired, even after getting rest.
- Feeling weak or not able to do as much physical activity as usual.
- Shortness of breath or trouble breathing with activity or even at rest.
- Swelling in the legs, ankles or feet.
- Not feeling very hungry.
- Losing weight without trying.
- Numbness, tingling or burning in the hands or feet.
AL amyloidosis often affects the heart. If this happens, it's called cardiac AL amyloidosis. Symptoms can include:
- Chest pain, especially during activity.
- Low blood pressure.
- Fast, pounding or fluttering heartbeats.
- Feeling dizzy or fainting, especially after standing up.
- Swelling in the legs, ankles, feet or belly area, which can be a sign of heart failure.
If AL amyloidosis affects your kidneys, you may have foamy or frothy urine.
If the condition affects your digestive system, symptoms may include:
- Diarrhea, constipation or changes between the two.
- Nausea.
- Weight loss.
- Belly pain.
- Bleeding, such as blood in the stool, or black, tarry stools.
- Feeling full quickly during meals.
- Trouble swallowing.
Some people with AL amyloidosis also have:
- Easy bruising.
- Bruising or purple-colored skin around the eyes. Depending on skin color, this change may be easier or harder to see.
- Swollen tongue, called macroglossia.
Tell your healthcare team about all the symptoms you have. Your care team can do tests to find the cause of your symptoms. Your care team may test for amyloidosis if you have several of these symptoms together.
When to see a doctor
Make an appointment for a health checkup if you have symptoms of AL amyloidosis.
If you have AL amyloidosis, tell your care team about new symptoms or symptoms that get worse. Quick care matters because it may help limit further organ damage.
When to seek emergency care
AL amyloidosis can affect the heart. It can lead to serious heart symptoms.
Get medical help right away if you have:
- Chest pain.
- Sudden, severe shortness of breath.
- Very fast or irregular heartbeats with shortness of breath, chest pain or fainting.
病因
In all types of amyloidosis, proteins fold the wrong way and stick together. This causes deposits called amyloid. But the amyloid can form from different starting proteins.
In AL amyloidosis, the starting proteins come from white blood cells called plasma cells. Plasma cells make antibodies that help the body fight infection. Antibodies contain two types of light chains, called kappa and lambda. Everyone typically has both kappa and lambda light chains. In AL amyloidosis, one group of plasma cells makes too much of one of these types of light chains.
The group of plasma cells that has changed and makes the light chains that fold the wrong way is called a clone. A condition in which one group of plasma cells works differently from the other plasma cells is called a plasma cell disorder. Another name for it is a clonal plasma cell disorder.
An example of a plasma cell disorder is monoclonal gammopathy of undetermined significance (MGUS). MGUS is a condition in which a small group of plasma cells makes a harmful protein but does not cause organ damage. Some people are diagnosed with MGUS before they get AL amyloidosis. Once AL amyloidosis develops, the condition is no longer considered MGUS.
Multiple myeloma also is a plasma cell disorder. It's a cancer of the bone marrow. Some people have both AL amyloidosis and multiple myeloma.
Less commonly, AL amyloidosis happens with other blood conditions. Examples are:
风险因素
Growing older raises the risk of AL amyloidosis. The condition is more common in older adults, often those in their mid-60s.
Having a plasma cell disorder called monoclonal gammopathy of undetermined significance (MGUS) also may raise your risk. But most people with MGUS do not develop AL amyloidosis.
并发症
AL amyloidosis causes harmful proteins to build up in the body's organs and tissues. The complications depend on the part of the body affected.
Possible complications include:
- Heart failure. This condition is common with AL amyloidosis. The amyloid deposits make the heart thick and stiff. That makes it harder for the heart to stretch and fill with blood. When this happens, it's called restrictive cardiomyopathy. The heart can't pump enough blood to meet the body's needs. Without treatment, heart failure can be life-threatening.
- Irregular heartbeats, called arrhythmias. Damage from AL amyloidosis can affect the electrical signals that tell the heart to beat. The heart may beat too fast or too slow. Or the heartbeat may not follow a steady pattern. Some irregular heartbeats can lead to fainting, stroke or, rarely, sudden cardiac arrest.
- Kidney damage. AL amyloidosis can cause the body to pass too much protein in the urine. This is called nephrotic syndrome. The syndrome can cause the kidneys to stop working as they should over time. A severe loss in the kidneys' ability to work is called end-stage kidney disease. A lot of protein loss from the kidneys also raises the risk of blood clots.
- Nerve damage. Amyloid can damage nerves that control feeling and movement. This can lead to numbness, pain or weakness. Damage also can affect the part of the nervous system that controls digestion, sexual function and blood pressure.
- Liver or digestive system damage. Amyloid can make the liver swell and affect how it works. The changes may make it harder for the body to absorb nutrients. Changes in the digestive tract may cause symptoms such as nausea, diarrhea, constipation, weight loss or bleeding.
- Bleeding. AL amyloidosis can cause low levels of a protein that helps blood clot. That protein is called factor X. If blood doesn't clot, you may be at risk of easy bruising and serious bleeding.
Regular health checkups can help your care team watch for these complications.
Sept. 01, 2026