In 2007, a group of American researchers discovered a new, very rare type of amyloidosis — one that targets a person’s kidneys. (1)
Like other forms of amyloidosis, this newly discovered type involves the improper folding of protein molecules. This improper folding leads to the harmful buildup of amyloid, which is the name for the fibrous clumps of protein molecules that then accumulate in the body.
LECT2 Amyloidosis Usually Affects the Kidneys and May Be Confused With Other Types
This new form of amyloidosis is thought to involve a type of blood protein called leukocyte chemotactic factor 2 (LECT2), which is made in the liver and circulates throughout the body. (2) Scientists are still working out what role LECT2 plays in our bodies, but current research suggests it plays a part in immune function as well as many other physiological processes. (The word “leukocyte” refers to white blood cells that help defend the body from harmful invaders.)
There’s some evidence that the LECT2 protein is involved with cell growth and repair, but further research is required to understand its specific function in the cell. (3) LECT2 is a unique protein in that it can form amyloid deposits even in its unmutated form, according to a 2022 review.
LECT2 amyloidosis (known as ALECT2 for short) is considered a systemic form of amyloidosis, meaning it is not confined to one part of the body (thanks to the leukocyte chemotactic factor 2 circulating throughout the body). It can cause amyloid buildup in someone’s liver, spleen, colon, and adrenal glands. But in a majority of cases, ALECT2 causes the accumulation of amyloid in the kidneys (though doctors aren’t sure exactly why this happens). (2)
Because another, more common form of amyloidosis — known as AL amyloidosis — can also cause kidney problems, there’s evidence that ALECT2 is sometimes misdiagnosed as the AL type. (2) This is a problem because AL amyloidosis is occasionally treated with chemotherapy — something that won’t help people with LECT2 amyloidosis, and which can be very harmful. (3)
There are no set figures on the number of patients with LECT2 amyloidosis. But the disease is thought to be quite rare, accounting for approximately 3 percent of all amyloidosis cases. Men and women are affected equally. (3,4) However, it seems to be much more common among people with Hispanic ancestry. (5) Also, though doctors have diagnosed ALECT2 in patients as young as age 43, the average age of diagnosis is 66. (2) Only a very small number of people have ever been diagnosed with ALECT2 before age 50. (1)
Fortunately, the prognosis for ALECT2 is better than that of AL and AA types. That said, the kidney is the most commonly involved organ in ALECT2, and when affected, ALECT2 can result in nephrotic syndrome or kidney failure if not treated. (4)
The Most Common Symptoms of LECT2 Amyloidosis Are Kidney Problems
Because LECT2 amyloidosis can cause problems in a number of different organs, its symptoms come in many types and levels of severity. But the most common symptoms of ALECT2 are related to kidney dysfunction, involving nephrotic syndrome. These symptoms include high levels of protein in the urine, high cholesterol levels, low blood protein levels, and swelling in the legs and arms. (2)
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LECT2 Amyloidosis Is Diagnosed With Urine Analysis and Kidney Biopsy
Most ALECT2 patients end up seeing a doctor because of kidney-related complaints like those mentioned above — fatigue, high cholesterol, swelling of the limbs, and other symptoms associated with kidney damage. These sorts of complaints lead to a urine analysis. If that analysis reveals that a patient has high levels of protein in their urine, your doctor may want to examine the type of protein found in the urine. If necessary, a follow-up kidney biopsy may reveal the buildup of amyloid. (2)
While these initial steps can help a doctor diagnose a patient with amyloidosis, more complicated testing is required to identify ALECT2. All of these tests involve closely examining the biopsied tissue to determine what type of amyloid they contain.
More Research Is Needed to Better Identify Treatments for LECT2 Amyloidosis
There are no treatments specifically designed for LECT2 amyloidosis. Most patients are treated with diuretics and other medications that help manage urine production and body fluid levels.
Low-sodium diets may also be helpful because they reduce the body’s retention of water. People with the disorder are told to limit their fluid intake to about 50 ounces (1.5 liters) a day, and to spread that intake evenly throughout the day (6). In severe cases, ALECT2 patients may require dialysis (blood purification) or a kidney transplant. (2)
Because ALECT2 amyloidosis is a relatively newly discovered disease, doctors are still trying to get a handle on its specific symptoms, its progression, and the best methods of treatment. (2) A lot more research is needed, but scientists and doctors are working to better understand this disease.