Question 1

What is CD55 deficiency (CHAPLE disease)?

Accepted Answer

CD55 deficiency, also known as CHAPLE disease (Complement Hyperactivation, Angiopathic Thrombosis, and Protein-Losing Enteropathy), is a rare genetic disorder where the immune system overreacts and damages intestinal and vascular tissues.
[Source]

Question 2

What are the symptoms of CD55 deficiency?

Accepted Answer

Symptoms can include severe diarrhea, low protein levels, weight loss, fatigue, anemia, blood clots, and frequent infections. Many patients experience swelling (edema) and nutrient loss due to protein-losing enteropathy.

Question 3

What causes CD55 deficiency?

Accepted Answer

CD55 deficiency is caused by mutations in the CD55 gene, which normally helps regulate part of the immune system called the complement pathway. When CD55 is missing or nonfunctional, the immune system can overreact and damage healthy tissues.

Question 4

How is CHAPLE disease diagnosed?

Accepted Answer

CHAPLE disease is diagnosed through genetic testing, blood tests showing low protein or complement activation, and sometimes a biopsy of the small intestine. Early diagnosis is important to begin treatment before complications develop.

Question 5

Is CD55 deficiency inherited?

Accepted Answer

Yes, CD55 deficiency is an inherited autosomal recessive disorder, meaning a child must inherit two copies of the mutated gene - one from each parent - to develop the condition.

Question 6

What is the function of CD55 in the body?

Accepted Answer

CD55, also called decay-accelerating factor (DAF), helps protect healthy cells from immune system attack by regulating the complement system. It acts like a shield against overactive immune responses.

Question 7

What happens when CD55 is deficient?

Accepted Answer

When CD55 is lacking or nonfunctional, the body’s complement system becomes overactive, which can damage blood vessels and the lining of the intestines. This leads to chronic inflammation, blood clots, and nutrient loss.

Question 8

How is CHAPLE disease treated?

Accepted Answer

Complement inhibitors like eculizumab or pozelimab are used to control symptoms, along with nutritional and anticoagulant support.
[FDA Source]

Question 9

What is the prognosis for someone with CD55 deficiency?

Accepted Answer

With proper treatment, most patients experience symptom relief and improved quality of life.
[Source]

Question 10

How rare is CHAPLE disease?

Accepted Answer

CHAPLE is extremely rare, with fewer than 100 reported cases worldwide.
[Source]

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