Fibrinogen alpha amyloidosis: insights from proteomics

Area of Science:

• Nephrology
• Genetics
• Proteomics

Background:

• Systemic amyloidosis, though rare, is a severe condition leading to organ failure.
• Accurate amyloid typing is critical for determining the causative protein and guiding treatment strategies.
• The kidneys are frequently affected in systemic amyloidosis, with hereditary renal amyloidosis being a significant concern.

Purpose of the Study:

• To highlight the importance of amyloid typing in systemic amyloidosis.
• To discuss the role of mass spectrometry in amyloid protein identification.
• To address challenges in diagnosing specific mutations, such as those in fibrinogen alpha chain amyloidosis (AFib).

Main Methods:

• Mass spectrometry-based proteomics for sensitive and accurate amyloid typing.
• Biopsy and histological analysis for initial diagnosis.
• Gene sequencing to identify specific mutations, particularly in hereditary forms like AFib.

Main Results:

• Mass spectrometry is established as the most sensitive and specific method for amyloid typing.
• Fibrinogen alpha chain amyloidosis (AFib), linked to FGA gene mutations, is the most common hereditary renal amyloidosis.
• Identifying 'private' frameshift mutations in the fibrinogen alpha chain can be challenging.

Conclusions:

• Accurate diagnosis of systemic amyloidosis requires precise identification of the causative protein.
• Mass spectrometry, combined with expert pathologist review and gene sequencing, enables confident diagnosis, even for complex mutations.
• Effective management of amyloidosis hinges on timely and accurate typing of the amyloid protein.