NLRP12 gene mutation in India: case finding and diagnosis made easy in the days of whole exome sequencing

NLRP12 c.1382dup promotes the development of Crohn's disease through the ERK/NLRP3/ IL-1β pathway

Whole-genome sequencing was used to identify a dominant inherited NLRP12 c.1382dup mutation in refractory familial Crohn's disease (CD) patients. Additionally, we observed a T insertion at position 1382 in the third exon of NLRP12, leading to a frameshift mutation. Isolation of peripheral blood from mutation carriers and subsequent experiments demonstrated increased interleukin (IL)-1β in CD patients with the NLRP12 c.1382dup mutation. However, the mechanisms by which the NLRP12 c.1382dup mutation mediates IL-1β remain unclear. Our research findings reveal a close correlation between elevated p-ERK levels and increased expression of NLRP3 and IL-1β in the presence of the NLRP12 c.1382dup mutation. Further experiments demonstrate that inhibiting p-ERK with PD98059 effectively reduces the production of NLRP3 and IL-1β. This discovery provides new insights into the pathogenesis of CD, highlighting the significant role of the ERK/NLRP3/IL-1β pathway in the progression of CD. Not only does this offer novel therapeutic targets for treating CD, but it also lays the groundwork for the development of treatment strategies targeting this pathway.

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.