Characterization of a Novel Pathogenic PLCG2 Variant Leading to APLAID Syndrome Responsive to a TNF inhibitor.

OBJECTIVE: Autoinflammation and PLCγ2-associated antibody deficiency and immune dysregulation (APLAID) syndrome is an autoinflammatory disease caused by gain-of-function variants in PLCG2. This study investigates the pathogenic mechanism of a novel variant of PLCG2 in a patient with APLAID syndrome. METHODS: Whole exome sequencing and Sanger sequencing were used to identify the pathogenic variant in the patient. Single-cell RNA sequencing, immunoblotting, luciferase assay, IP-one ELISA, calcium flux assay, quantitative PCR, and immunoprecipitation were used to define inflammatory signatures and evaluate the effects of the PLCG2 variant on protein functionality and immune signaling. RESULTS: We identified a novel de novo variant, PLCG2 p.D993Y, in a patient with colitis, pansinusitis, skin rash, edema, recurrent respiratory infections, B cell deficiencies, and hypogammaglobulinemia. The single-cell transcriptome revealed exacerbated inflammatory responses in the patient's PBMCs. Expression of the D993Y variant in HEK293T, COS-7, and PLCG2 knock-out THP-1 cell lines showed heightened PLCγ2 phosphorylation, elevated IP3 production and intracellular Ca2+ release, and activation of the MAPK, NFκB, and NFAT signaling pathways compared to control-transfected cells. In vitro experiments indicated that the D993Y variant altered amino acid properties, disrupting the interaction between the catalytic and auto-inhibitory domains of PLCγ2, resulting in PLCγ2 auto-activation. CONCLUSIONS: Our findings demonstrated that the PLCG2 D993Y variant is a gain-of-function mutation via impairing its auto-inhibition, activating multiple inflammatory signaling pathways, thus leading to APLAID syndrome. This study further broadens the molecular underpinnings and phenotypic spectrum of PLCγ2-related disorders.

Whole-exome sequencing reveals an association of rs112065068 in TGOLN2 gene with distant metastasis of non-small cell lung cancer.

Early prediction and prevention of recurring illness is critical for improving the survival rates of patients with non-small cell lung cancer (NSCLC). Previously, we demonstrated that the presence of premalignant epithelial changes in the small bronchi distant to the primary tumor is associated with NSCLC progression: isolated basal cell hyperplasia (iBCH) indicates a high risk of distant metastasis, BCH combined with squamous metaplasia (BCHSM) - a high risk of locoregional recurrence. Here, we aimed to identify germline single nucleotide variants (SNVs) and insertions and deletions (InDels) associated with distant metastasis and locoregional recurrence in cases with iBCH and BCHSM using whole-exome sequencing of 172 NSCLC patients. The rs112065068 of the TGOLN2 gene was identified only in iBCH patients and was associated with a high risk of distant metastasis (P < .001) and worse metastasis-free survival (HR = 4.19 (95 %CI 1.97-8.93); P < .001). This variant was validated in a group of 109 NSCLC patients using real-time PCR and Sanger sequencing analyses. To our knowledge, this study is the first to identify a germline variant associated with NSCLC distant metastasis.