Familial Amyloidosis

Amyloidosis is a disease in which the body produces abnormal proteins called amyloid. Deposits of these proteins build up in tissues and organs of the body and can cause a range of symptoms. There are various types of amyloidosis, including primary amyloidosis, secondary amyloidosis, and familial amyloidosis.

Causes of familial amyloidosis

Familial amyloidosis, also called ATTR amyloidosis, is caused by an abnormal gene inherited from an affected parent. The most common form is caused by the transthyretin (TTR) protein, and more than 100 mutations of this protein have been associated with the disease.

Familial amyloidosis is autosomal dominant, which means that a child has a 50% chance of inheriting the disease if just one parent carries the genetic trait for it.

Symptoms of familial amyloidosis

Although the abnormal gene is present at birth, symptoms do not appear until later in life, after amyloid deposits have accumulated. Familial amyloidosis often affects the liver, heart, kidneys, and nerves.

Symptoms may include:

  • Neuropathy (numbness or tingling in the hands and feet)
  • Cardiomyopathy (enlargement of the heart)
  • Irregular heartbeat
  • Diarrhea or constipation
  • Weight loss
  • Dizziness upon standing (orthostatic hypotension)
  • Swelling of the legs and ankles
  • Weakness
  • Shortness of breath
  • Severe fatigue
  • Purplish patches around the eyes
  • Enlarged tongue
  • Skin changes such as easy bruising or thickening
  • Protein in the urine

If the disease causes damage to the kidney, nerves, or heart, such damage can be life threatening.

Diagnosing familial amyloidosis

The following tests may be used to diagnose familial amyloidosis:

  • Blood tests
  • Urine tests
  • Physical exam
  • Tissue biopsy

Treatments for familial amyloidosis

The primary treatment for familial amyloidosis is liver transplantation. The abnormal TTR protein is made in the liver, but a newly transplanted liver will make only normal transthyretin protein.

In addition to liver transplantation, other supportive measures may be needed to address the effects of amyloidosis on other organs. For instance if the kidneys are affected, patients may need to take diuretics, restrict dietary salt, wear compression garments, and elevate their legs to reduce swelling. Dietary changes and medications may be needed to treat gastrointestinal effects.