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Incidence of TNFRSF1A mutations in German children: epidemiological, clinical and genetic characteristics.

OBJECTIVE
TNF receptor 1-associated periodic syndrome (TRAPS) is a rare disease belonging to the heterogeneous group of hereditary periodic fever (HPF) syndromes. By their monogenic origins, the HPF syndromes are clearly differentiated from other periodic inflammatory episodes occurring in autoimmune, neoplastic and infectious diseases. We aim to determine the incidence of TRAPS and the spectrum of mutations in the TNFRSF1A gene, and to give a brief survey of clinical signs.


METHODS
A prospective surveillance of children with TRAPS was conducted in Germany during a time period of 3 years (2003-06). Monthly inquiries were sent to 370 children's hospitals by the German Pediatric Surveillance Unit (Clinic-ESPED, n1) and to 23 laboratories (Laboratory-ESPED, n2). Inclusion criteria were TNFRSF1A mutation-positive patients < or =16 years of age, more than three self-limiting episodes of fever >38.5 degrees C, and increased inflammation markers. Clinical, epidemiological and genetic data were evaluated via questionnaires.


RESULTS
Of the 23 cases included, 19 were identical in 20 clinical and 22 laboratory reports. The incidence of TRAPS in German children was estimated to be approximately 5.6 per 10(7) person-years. In 20 TRAPS patients of the Clinic-ESPED, median age of onset and duration of fever periods were 6 (range 1-16) years and 6.3 (range 2-24) days, respectively. Main symptoms were arthralgia, abdominal pain, lymphadenopathy, headache and skin involvement. The R92Q substitution was found in 19 (83%) of 23 cases.


CONCLUSION
The incidence of TRAPS is low and corresponds to 6-10 newly diagnosed patients < or =16 years per year in Germany.