Genetic and clinical features of cryopyrin-associated periodic syndromes in Turkish children.

Objectives: The aim of this study was to present the genetic and clinical data of the largest cohort of Turkish cryopyrin-associated periodic syndromes (CAPS) patients.
Methods: This is a two-centre descriptive study of Turkish children with clinical diagnosis of CAPS. NLRP3 analyses were performed by Sanger sequencing and by massively parallel sequencing. ASC dependent NF-κB activation and transfection-induced THP-1 cell death assays determined the functional consequences of the detected variants. Disease activity and response to anti interleukin 1 (anti-IL-1) treatment was also assessed.
Results: Heterozygous germline NLRP3 mutation was detected in 8 of 14 enrolled patients (57.1%). Two novel somatic mutations Y560H and G307D were found which induced both THP-1 cell death and ASC dependent NF-kB activation. With anti-IL-1 treatment the disease activity was improved in all patients except one. Except two patients with macrophage activation syndrome (MAS) attack, there were no serious adverse events requiring hospitalisation.
Conclusions: CAPS should be considered in all patients with typical symptoms even if Sanger-based genetic analysis is negative, since a considerable number of patients have mosaicism. Treatment should be patient-tailored and MAS should be considered as a rare complication.