The formation and deposition of fibrils derived from immunglobulin light chains is a hallmark of systemic AL amyloidosis. A particularly remarkable feature of the disease is the diversity and complexity in pathophysiology and clinical manifestations. This is related to the variability of immunoglobulins, as virtually every patient has a variety of mutations resulting in their own unique AL protein and thus a unique fibril deposited in the body. Here, I review recent biochemical and biophysical studies that have expanded our knowledge on how versatile the structure of AL fibrils in patients is and highlight their implications for the molecular mechanism of fibril formation in AL amyloidosis.
