ABSTRACT
Senile systemic amyloidosis may be derived from the wild type of transthyretin and it is postulated that the monomer frequently undergoes proteolytic digestion. The most frequent type of cardiac amyloid is derived from the immunoglobulin light chain; however, it is increasingly recognized that among older patients amyloid derived from transthyretin (ATTR) is within the main differential diagnosis. Examination of the amyloid tissue deposits demonstrated two closely related peaks corresponding to TTR monomer. One peak, which was shorter by 2 amino acids, was twice as abundant. The negative control sample did not demonstrate a dominant peak in the corresponding region. Endomyocardial biopsy showed abundant interstitial deposits of ATTR; deposits were also detectable in several gastro-intestinal biopsies. At autopsy, very abundant interstitial deposits of amyloid were present in the myocardium and both lungs. Less abundant interstitial deposits were also seen in the skeletal muscles and adjacent adipose tissue.
