This condition is fairly rare and is characterized by the deposition of amyloid (a protein) in the kidneys. The sequelae of this amyloid deposition is inflammation, inability of the kidneys to function normally (kidney disease) and protein loss. Because it presents similarly to other glomerular diseases, definitive diagnosis requires biopsy, which is not commonly performed. Though the condition is not reversible and carries a worrisome prognosis, some aspects of it can be treated. It is believed that there is a genetic predisposition to this condition in some breeds, such as Abyssinian cats, for example.
1) Veterinary Partner. Veterinarypartner.com
2) Tilley, L. P., & Smith, F. W. (2005). The 5-minute veterinary consult: Canine and feline. Philadelphia: Lippincott Williams & Wilkins.