Manthiram K, Preite S, Dedeoglu F, Demir S, Ozen S , et al.
Proceedings of the National Academy of Sciences of the United States of America •
Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is the most common periodic fever syndrome in children. The disease appears to cluster in families, but the pathogenesis is unknown. We queried two European-American cohorts and one Turkish cohort (total = 231) of individuals with PFAPA for common variants previously associated with two other oropharyngeal ulcerative disorders, Behçet's disease and recurrent aphthous stomatitis. In a metaanalysis, we found that a variant upstream of (rs17753641) is strongly associated with PFAPA (OR 2.13, = 6 × 10). We demonstrated that monocytes from individuals who are heterozygous or homozygous for this risk allele produce significantly higher levels of IL-12p70 upon IFN-γ and LPS stimulation than those from individuals without the risk allele. We also found that variants near , , and were significant susceptibility loci for PFAPA, suggesting that the pathogenesis of PFAPA involves abnormal antigen-presenting cell function and T cell activity and polarization, thereby implicating both innate and adaptive immune responses at the oropharyngeal mucosa. Our results illustrate genetic similarities among recurrent aphthous stomatitis, PFAPA, and Behçet's disease, placing these disorders on a common spectrum, with recurrent aphthous stomatitis on the mild end, Behçet's disease on the severe end, and PFAPA intermediate. We propose naming these disorders Behçet's spectrum disorders to highlight their relationship. alleles may be factors that influence phenotypes along this spectrum as we found new class I and II associations for PFAPA distinct from Behçet's disease and recurrent aphthous stomatitis.
The Periodic fever syndromes (PFS) are a group of disorders of the innate immune system. We investigated patients diagnosed with PFS at the Dartmouth Hitchcock Pediatric Rheumatology Clinic. Case acquisition was performed by reviewing ICD 9/10 coded records for familial Mediterranean fever (ICD 9 277.31), laboratory test records for PFS genetic screening, and clinic records between 1/1/2011 and 12/31/2017. Twenty-seven cases had clinical evaluations including PFS genetic screening. Clinical diagnoses included familial Mediterranean fever (FMF) (10 cases), Muckle-Wells (2 cases), tumor necrosis factor receptor associated periodic syndrome (TRAPS) (4 cases), hyper IgD syndrome (HIDS) (1 case), Crohn's Disease (1 case), systemic onset juvenile idiopathic arthritis (SoJIA) (1 case), fever of unknown origin (FUO) (1 case), periodic fever adenitis pharyngitis aphthous ulcer (PFAPA) (6 cases), and cold-induced urticaria (1 case). Fifteen cases were associated with a genetic cause. Seven of the 10 FMF cases were confirmed genetically and were either heterozygous or compound heterozygotes. Both cases of Muckle-Wells had either a compound heterozygote for CIAS 1 or a NOD gene mutation. Both TRAPS cases presented atypically with patients developing systemic lupus erythematosus (SLE) or being asymptomatic. Two patients had novel syndromes. One FMF patient had a TRNT1 gene mutation who responded to intravenous immunoglobulin (IVIg) and colchicine after failing multiple treatments. The other had SoJIA with a LPIN 2 gene mutation but responded to colchicine. Only one of the 15 genetically proven cases had classical presentation and genetics (HIDS secondary to a mevalonate kinase (MVK) gene mutation). PFS screening was helpful in over half of the cases to develop therapeutic treatment plans. Given the atypical clinical presentations seen with genetically determined PFS, extensive genetic testing is indicated for all patients presenting with a PFS, excluding classical PFAPA syndrome.
