Clinically Different Presentations of Family Members With the Same Homozygote Diacylglycerol Kinase Epsilon Mutation: Case Report

Membranoproliferative glomerulonephritis and renal microangiopathies may manifest similar clinical presentations and histology. Many genetic mutations that cause these diseases have been reported. Studies on mutations in the gene encoding diacylglycerol kinase epsilon identified a novel pathophysiologic mechanism leading to atypical hemolytic uremic syndrome and/or membranoproliferative glomerulonephritis. Here, we present the different clinical presentations and treatments in 4 family members who carried the same homozygous diacylglycerol kinase epsilon mutation. The first patient (age 5 years, 3 months old at diagnosis) had nephrotic syndrome. The kidney biopsy was membranoproliferative glomerulonephritis; partial remission was achieved with cyclophosphamide, cyclosporine, and mycophenolate mofetil treatment. The second patient (age 5 years, 7 months at diagnosis) presented with overlapping atypical hemolytic uremic syndrome and membranoproliferative glomerulonephritis. Remission could not be achieved with cyclophosphamide, cyclosporine, and mycophenolate mofetil, and hemodialysis treatment was started. At 10 years from first admission, the patient had end-stage kidney disease, and kidney transplant was performed successfully. The third patient was admitted with the diagnosis of nephrotic syndrome at 13 months of age, kidney biopsy showed membranoproliferative glomerulonephritis, and spontaneous remission developed during followup. He presented with hemolytic uremic syndrome 15 months after the first admission, and dialysis was started. Remission was achieved with plasma infusion and eculizumab treatment. The fourth patient (a 7-month-old boy and brother of patient 3) had no clinical or laboratory findings. All patients had genetic analysis, and mutation in exon 2:c.473G>A(p. W158*) was detected. Our related patients with the same mutation showed different clinical and histological findings. However, we did not observe a clear genotype-phenotype correlation in patients with diacylglycerol kinase epsilon nephropathy, suggesting additional factors mediating phenotypic heterogeneity.