Apolipoprotein A-IV Associated Amyloidosis ICD-10: E85.8; ICD-11: 5D00.2Y

Rare, nonhereditary, systemic amyloidosis characterized by slowly progressive renal dysfunction, elevated serum creatinine, usually normal urinalysis without significant proteinuria, and associated cardiac disease. Cardiac involvement manifests as hypertrophic obstructive cardiomyopathy, left ventricular outflow tract obstruction, coronary artery disease, and conduction system abnormalities.

m>w

Average age of 63.5 years (Dasari S et al. 2016).

Signs of renal insufficiency, monoclonal gammopathy is possible

Renal biopsy results showed large amounts of eosinophilic Congo red-positive amyloid deposits that were confined to the renal medulla and spared the renal cortex. Detection of peritubular amyloid possible. Later signs of renal tubular atrophy, interstitial fibrosis, and glomerular sclerosis.

Electron microscopy showed nonbranched fibrils 7 to 10 nm in diameter.

Laser microdissection of amyloid deposits and subsequent mass spectrometry usually yielded a large number of spectra (a semiquantitative measure of abundance) for AApoAIV protein between 49 and 169 (average 85), serum amyloid protein (average 19), and apolipoprotein E (average 48) (Dasari S et al. 2016).

1. Dasari S et al (2016) Clinical, biopsy, and mass spectrometry characteristics of renal apolipoprotein A-IV amyloidosis. Kidney Int. 90:658-664.
2. Said SM et al (2013) Renal amyloidosis: origin and clinicopathologic correlations of 474 recent cases. Clin J Am Soc Nephrol 8:1515-1523.
3. Sethi S et al (2012) Medullary amyloidosis associated with apolipoprotein A-IV deposition. Kidney Int 81:201-206