Challenges in classification of novel CFH variants in patients with atypical hemolytic uremic syndrome

Abstract

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by dysregulation of the alternative pathway of complement. Heterozygous variants in complement and complement regulatory proteins may increase risk for aHUS and, to date, the highest frequency of disease-causing variants in aHUS has been identified in the CFH gene encoding complement factor H. Clinical laboratory classification of variants identified in CFH can be challenging, particularly in the case of novel variants. In this report, we describe 6 patients with aHUS found to have rare variants in CFH and highlight challenges faced with variant classification in rare disorders such as aHUS.

Keywords

• Alternative pathway
• Thrombotic microangiopathy
• Complement factor H
• Genetic variant classification