Background Autoinflammatory diseases (AUID) is a group of disorders characterized by dysfunction of innate immunity which caused by gene mutations leading to coded proteins changes, finally causing uncontrolled systemic inflammation. AUID are usually diagnosed during pediatric age. However, adult-onset disease or diagnosis during adulthood has been occasionally described. Moreover, AUID have been hardly reported in the Chinese population.
Objectives We aimed to characterize the clinical and genetic phenotypes of Chinese adult patients with AUID.
Methods We prospectively evaluated clinical and genetic features of adult patients (≥16 years) suspected monogenic AUID in the period April 2015 to May 2016, at the adult AUID center, Department of Rheumatology, Peking Union Medical College Hospital. The definite diagnosis of each disease was deemed to be present if both clinical phenotypes and genetic confirmation were met.
Results During the study period, a total of 37 adult patients with clinical phenotypes suspicious of monogenic AUID requested for a genetic study. A final diagnosis of monogenic AUID was achieved in 16 patients (43.2% of patients tested). Two additional patients were diagnosed with periodic fever, aphthous stomatitis, pharyngitis and adenitis (PFAPA) syndrome. Finally, a total of 18 patients with AUID were diagnosed and follow-up in our center, including 7 (38.9%) familial Mediterranean fever (FMF), 2 (11.1%) tumor necrosis factor-receptor associated periodic syndrome (TRAPS), 3 (16.7%) cryopyrin-associated periodic syndrome (CAPS), 3 (16.7%) NLRP12-autoinflammtory disease (NLRP12-AD), 1 (5.6%) Blau syndrome (BS), and 2 (11.1%) PFAPA. Disease onset during adulthood was observed in 15 (83.3%) patients, and the final diagnosis was delayed with a mean time of 10 years. Adult AUID patients usually carried low-penetrance mutations and gene variants were presented as heterozygosis or compound heterozygosis.
Conclusions Adult AUID is not uncommon. FMF, CAPS, and NLRP12-AD are relatively common monogenic AUID in Chinese adult patients. Adult-onset AUID may be related to the presence of low-penetrance mutations, being characterized by nonspecific, incomplete or atypical disease patterns, leading to a delay of diagnosis. The interpretation of gene analysis in adult suspected AUID should be performed with caution, and if possible, should be referred to expert physicians in the field in adult AUID center.
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Disclosure of Interest None declared