Amyloidosis is a condition that occurs when amyloid, a substance composed of abnormally folded protein, is deposited in various organs of the body. Some types of amyloidosis are hereditary in dogs. (Chinese Shar-Peis are known to be at risk for hereditary amyloidosis.) Others occur as a result of diseases such as heartworm infection, various cancers, or other inflammatory or immune-related conditions. However, the cause is often unknown.

Amyloid can be deposited throughout the body, or in just one specific area. This causes damage by displacing normal cells. The disease can become fatal if amyloid is deposited into the tissue of critical organs, such as the kidneys, liver, or heart. All domestic mammals may develop amyloidosis, and aged animals commonly have minor deposits of amyloid without signs or problems.

There are several types of amyloid, and the classification of amyloidosis is based on which amyloid protein is involved. Deposits of AA amyloid can result from chronic inflammatory diseases, chronic bacterial infections, and cancer. The amyloid is usually deposited in organs such as the spleen or kidneys. The animal may not show any signs of disease. If AA amyloid is deposited in the kidneys, it can lead to a buildup of protein and result in kidney failure. AL amyloid is another common form of amyloid. AL amyloid tends to be deposited in nerve tissue and joints.

Because of its wide distribution and stealthy onset, amyloidosis is difficult to diagnose. However, your veterinarian might suspect amyloidosis if your dog has a chronic infection or inflammation and develops kidney or liver failure. No specific treatment can prevent the development of amyloidosis or promote the reabsorption of the protein deposits.

Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); David A. Ashford, DVM, MPH, DS; Craig E. Greene, DVM, MS; Eugene D. Janzen, DVM, MVS; Bert E. Stromberg, PhD; Max J. Appel, DMV, PhD; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Kenneth R. Harkin, DVM, DACVIM; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD; Jodie Low Choy, BVMS; Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM