Fibrinogen alpha amyloidosis: insights from proteomics

Introduction: Systemic amyloidosis is a diverse group of diseases that, although rare, pose a serious health issue and can lead to organ failure and death. Amyloid typing is essential in determining the causative protein and initiating proper treatment. Mass spectrometry-based proteomics is currently the most sensitive and accurate means of typing amyloid. Areas covered: Amyloidosis can be systemic or localized, acquired or hereditary, and can affect any organ or tissue. Diagnosis requires biopsy, histological analysis, and typing of the causative protein to determine treatment. The kidneys are the most commonly affected organ in systemic disease. Fibrinogen alpha chain amyloidosis (AFib) is the most prevalent form of hereditary renal amyloidosis. Select mutations in the fibrinogen A alpha (FGA) gene lead to AFib. Expert commentary: Mass spectrometry is currently the most specific and sensitive method for amyloid typing. Identification of the mutated fibrinogen alpha chain can be difficult in the case of 'private' frameshift mutations, which dramatically change the sequences of the expressed fibrinogen alpha chain. A combination of expert pathologist review, mass spectrometry, and gene sequencing can allow for confident diagnosis and determination of the fibrinogen alpha chain mutated sequence.