Cryofibrinogen-Associated Glomerulonephritis

Cryofibrinogen is an under-recognized cryoprotein. Cryofibrinogen is a cryoprecipitate that develops following plasma refrigeration, but does not occur in cold serum. People with cryofibrinogenemia may be asymptomatic, but this cryoprotein can be associated with thromboembolic disease, particularly affecting the skin. Kidney manifestations are relatively uncommon, but are likely underestimated. We describe clinical features and kidney biopsy results in 2 patients with cryofibrinogen-related kidney disease.