A novel compound heterozygous mutation in DGKE in a Chinese patient causes atypical hemolytic uremic syndrome

Abstract

Objectives:DGKE mutations can lead to hemolysis and thrombus in patients with atypical hemolytic uremic syndrome (aHUS). However, the sequence variants of DGKE in Chinese patients with aHUS have not been reported, and the protein function and crystal structure of DGKE remain unresolved. Methods: Targeted exome sequencing was accomplished in one affected patient from each family using the Illumina NextSeq 500 platform. Protein modeling and functional analysis in DGKE were also performed to understand the impact of identified variants on the phenotype. Results: We report a novel compound heterozygous mutation in the DGKE gene in a Chinese consanguineous family in which a child was diagnosed with aHUS, which includes a c.231C>G missense mutation and a c.790_791delTG frameshift mutation derived from his father and mother, respectively. Our bioinformatic analysis suggested that the allelic mutations at different sites in DGKE yield abnormal crystal structures and conformations, leading to dysregulation of its downstream signaling. Conclusions: Our study further expands the spectrum of the sequence variants reported in the DGKE gene and also indicates that different races may have different DGKE variants. Moreover, the altered structures and conformations, caused by DGKE mutations, disrupt the binding of DGKE with its partners, and leading to the occurrence of aHUS.