Amyloidosis, often with a diagnostically suggestive distribution, eventually occurs in many cases of familial Mediterranean fever (FMF). It appears at variable times after the onset of classical attacks of abdominal pain and is not necessarily related to the frequency and number of the preceding episodes of abdominal pain. In a small number, amyloid is the earliest indication of disease and only subsequently do the characteristic symptoms of FMF become manifest.
Sohar et al1 described as phenotype 1 those cases in which the febrile painful attacks appeared first and phenotype 2, those in which amyloidosis appeared first. Of 114 patients with amyloidosis, 106 were phenotype 1 and 8 were phenotype 2. In five of the eight with phenotype 2, attacks of abdominal pain appeared later, while only in three did amyloid remain the sole manifestation. Follow up of these three was for a maximum of three years. Support for the
Hurwich BJ, Schwartz J, Goldfarb S. Record Survival of Siblings With Familial Mediterranean Fever, Phenotypes 1 and 2Case of Renal Vein Thrombosis Complicating the Amyloidosis (Phenotype 2). Arch Intern Med. 1970;125(2):308-311. doi:10.1001/archinte.1970.00310020114015