Variants in autoinflammatory diseases-related genes in a family with cold-induced autoinflammatory syndrome.

Objectives: To characterise what immunogenetic alterations are present in a Spanish family having several members with a familial cold-induced autoinflammatory syndrome (FCAS), a kind of autoinflammatory disease (AID).

Methods: We present the case of two sisters (cases 1 and 2) with a similar clinical picture since their childhood. The symptoms start after exposure to cold and consist of recurrent fever, papules or urticaria, and oedema in hands and fingers. The mother had similar symptomatology as her daughters, which remitted after her first pregnancy, whereas the father is healthy. Patients and their parents were genotyped in a panel of 14 candidate genes using Next-Generation Sequencing (NGS). Real-time PCR was used to quantify IL1β mRNA levels from LPS-stimulated monocytes. ELISA was used to measure the IL1β and IL18 concentrations in supernatants and sCD25 levels in sera. IL1β, IL4, IL6, IL8, IL10, IL17A, IL18 and TNF-α serum levels were assessed using xMAP® Technology.

Results: All the genetic variants found in this family are benign with two exceptions: NLRC4 p.Leu339Pro (present in both cases and their mother) and PSTPIP1 p.Gln219His (present in Case 1 and her father). The monocytes stimulated of the individuals with the NLRC4 variant produce higher levels of IL1β (protein and mRNA). Levels of TNF-α, IL4, and IL6 were higher in Case 1 than in the age-matched controls.

Conclusions: The familial segregation and the clinical picture compatible with FCAS suggest that NLRC4 p.Leu339Pro causes the AIDs syndrome diagnosed in several family members.