A rare case of an NLRP12-associated autoinflammatory disease

NLRP12-associated autoinflammatory disease: A novel causal mutation and bioinformatics analyses

Nucleotide-binding leucine-rich repeat-containing receptor 12-associated autoinflammatory disease (NLRP12-AID) is a rare autosomal dominant disorder. In this study, we reported a case of this rare disease with a novel NLRP12 mutation (A218V, rs749659859). The patient displayed typical symptoms, including recurrent fever, arthralgia, and skin allergies. Elevated serum IgE, decreased apolipoprotein A1, high-density lipoprotein cholesterol, and fluctuating levels of various leukocyte subtypes, procalcitonin, IL6, creatine kinase, and 25-hydroxyvitamin D were also detected. Inflammatory lesions were observed in multiple organs using 18F-FDG PET/CT. By mining single-cell transcriptome data, we identified relatively high expression of NLRP12 in monocytes compared to other human peripheral blood mononuclear cells. NLRP12-positive monocytes exhibited reduced expression of IL18, CCL3, and TNFA compared to NLRP12-negative monocytes. Structural analyses suggested that the A218V mutation, along with A218T and F402L, may reduce the ATP-binding affinity of the NLRP12 protein. These findings may provide new insights into the mechanisms of NLRP12-AID, and suggest the potential ATP-based therapy for further investigation.

A rare case of uncharacterized autoinflammatory disease: Patient carrying variations in NLRP3 and TNFRSF1A genes

Tumor necrosis factor type 1A receptor-associated periodic syndrome (TRAPS) and cryopyrin-associated autoinflammatory syndrome (CAPS) are rare monogenic autoinflammatory diseases (AIDs) mainly caused by pathogenic variations in the TNFRSF1A and NLRP3 genes, respectively. Here, we describe a unique patient presenting with symptoms overlapping both TRAPS and CAPS, without known pathogenic variants in the respective genes. The patient harbored the p.Val200Met variation in NLRP3 and the p.Ser226Cys variation in TNFRSF1A, prompting us to delve deeper into the functional analysis due to conflicting or inconclusive pathogenicity interpretations of the variants across various databases. Molecular dynamics analysis of the p.Val200Met variation in NLRP3 revealed a rigid conformation in the helical domain 2 subdomain of the NACHT domain. This increased rigidity suggests a potential mechanism by which this variation supports the assembly of the NLRP3 inflammasome. Notably, the patient's peripheral mononuclear blood cells demonstrated an elevated IL-1β response upon lipopolysaccharides (LPS) induction. Subsequent initiation of anti-IL-1β therapy resulted in a significant alleviation of the patient's symptoms, further supporting our hypothesis. We interpret these findings as suggestive of a potential pathophysiological role for the NLPR3 p.Val200Met variation in shaping the patient's clinical phenotype, which was also supported by clinical and genetic analysis of the family. This case underscores the complexity of the genetic landscape in AIDs and highlights the value of combining family genetic and functional data to refine the understanding and management of such challenging cases.

NLRP12-associated autoinflammatory disease in Chinese adult patients: a single-centre study

BACKGROUND

NLRP12-associated autoinflammatory disease (NLRP12-AID) is an autosomal dominant autoinflammatory disorder caused by variants of NLRP12 gene. We aimed to report a cohort of Chinese adult patients with NLRP12-AID and summarised phenotypes and genotypes.

METHODS

Twenty patients were diagnosed with NLRP12-AID after performing whole-exome sequencing and were included in our cohort. Demographic information, clinical data and treatment response were collected and evaluated. A literature review of NLRP12-AID was performed, and the clinical features and mutated sites were summarised and compared with our cohort.

RESULTS

Among the 20 NLRP12-AID patients, the main clinical features of NLRP12-AID included fever, cutaneous rash, arthralgia/arthritis, pharyngitis/tonsillitis, lymphadenopathy, myalgia and abdominal pain/diarrhoea. Thirteen NLRP12 variants were detected as F402L, G39V, R1030X, R7G, E24A, Q90X, A218V, A259V, W581X, G729R, R859W, c.-150T>C and c.*126G>C. Glucocorticoids were used in 14 patients, immunosuppressive agents in 13, and tocilizumab in 2. Seventeen patients had good responses to therapy. When compared with 50 NLRP12-AID patients from other countries, Chinese patients had fewer variants in exon 3, higher incidences of cutaneous rash, pharyngitis/tonsillitis and lymphadenopathy. Among all these 70 NLRP12-AID patients, patients carrying non-exon-3 variants had higher frequencies of ocular involvement, pharyngitis/tonsillitis, headache and lymphadenopathy than those with exon-3 variants.

CONCLUSION

This is the largest cohort of NLRP12-AID in the world and seven novel variants of NLRP12 were identified. Chinese adult patients of NLRP12-AID had more non-specific symptoms such as pharyngitis/tonsillitis and lymphadenopathy when compared with patients from other countries, for which the less occurrence of exon-3 variants might be one possible reason.

Autoinflammatory Recurrent Pericarditis Associated with a New NLRP12 Mutation in a Male Adolescent

Idiopathic recurrent pericarditis (IRP) can be the hallmark of an autoinflammatory syndrome with recurrent attacks of chest pain and symptom-free intervals following an acute episode. The recurrence rate may be 35% in the pediatric population, frequently with less severe manifestations than at the first episode. Pericarditis can be the sole clinical manifestation or may be part of a systemic autoinflammatory disease (SAID), especially in the case of a recurrence. Familial Mediterranean Fever (FMF), Tumor Necrosis Factor Receptor-Associated Periodic Syndrome (TRAPS), Mevalonate-Kinase Deficiency (MKD), nucleotide-binding oligomerization domain 2 (NOD2)-associated autoinflammatory syndrome, and others are closely related to IRP based on similar clinical manifestations and treatment responses to anti-interleukin 1 (IL-1) agents, such as anakinra, and should therefore be excluded in patients with IRP. A newly described SAID, an autosomal dominant disorder known as NLRP12-AID (nucleotide-binding leucine-rich repeat-containing receptor 12-related autoinflammatory disease) is caused by heterozygous mutations in the NLRP12 gene and most commonly affects children. Fewer than 40 pediatric patients with NLRP12-AID have been described in the medical literature, with none presenting with RP. We report a case of relapsing pericarditis responsive to anti-IL-1 therapy in a male adolescent who carried a missense mutation in the NLRP12 gene potentially causative of the excessive activation of inflammatory pathways. This is a unique case in the medical literature that associates recurrent pericarditis in an adolescent presumed to be related to the missense mutation in the NLRP12 gene. The role of the NLRP12 inflammasome in generating and maintaining recurrent pericardial inflammation should be considered.

Contrasting role of NLRP12 in autoinflammation: evidence from a case report and mouse models

Objective

To explore at the molecular level the phenotype of a patient suffering an autoinflammatory syndrome which was diagnosed as familial cold autoinflammatory syndrome type 2 (FCAS-2). To explore the functions of Nlrp12 in inflammation using mouse models.

Methods

Whole exome sequencing and Nlrp12 targeted resequencing were performed on DNA isolated from the patient and her family members. In vivo and ex vivo models of inflammation (urate crystals-dependent acute joint inflammation and urate crystals-induced peritonitis) were analysed in Nlrp12-deficient and Nlrp12-competent mice.

Results

A rare missense NLRP12 variant (c.857C>T, p.P286L) was identified in the patient and her healthy relatives. Nlrp12-deficient mice exhibit reduced systemic inflammation and neutrophilic infiltration.

Conclusion

Nlrp12 mediates proinflammatory functions in mice. In humans, the identification of Nlrp12 variants must be cautiously interpreted depending on clinical and paraclinical data to diagnose FCAS-2.