Analysis of genetic variants in a patient with Familial hemophagocytic lymphohistiocytosis

Objective: To explore the genetic basis for a patient with Familial hemophagocytic lymphohistiocytosis (FHL).

Methods: A 35-day-old male infant who was admitted to the Oriental Hospital Affiliated to Xiamen University on August 3, 2021 due to fever for over 7 hours was selected as the study subject. Whole exome sequencing (WES) was carried out for the proband and his parents, and candidate variants were selected based on the clinical phenotypes of the proband and confirmed by Sanger sequencing.

Results: WES and Sanger sequencing results revealed that the proband had harbored compound heterozygous c.67_71delinsGCCC and c.65delC variants of the PRF1 gene, which were respectively inherited from his mother and father. The c.67_71delinsGCCC variant was unreported previously. Based on the guidelines of American College of Medical Genetics and Genomics and clinical manifestations, it was classified as pathogenic (PVS1+PM2_Supporting+PM3+PP4). c.65delC was a known pathogenic variant (PVS1+PM2_Supporting+PM3_Strong+PP4).

Conclusions: The compound heterozygous variants of c.67_71delinsGCCC and c.65delC of the PRF1 gene probably underlay the disease in the proband. The identification of the novel variant has expanded the mutational spectrum of the PRF1 gene.