The periodic fever syndromes are autoinflammatory diseases that present with recurrent fever, serositis and rash. Familial Mediterranean fever is the most common periodic fever syndrome and characterized by recurrent attacks of fever, arthritis, peritonitis, pleuritis that typically last 1-3 days. Hyperimmunoglobulinemia D syndrome is another example of periodic fever syndromes and patients have recurrent fever attacks for 3-7 days accompanied by abdominal pain, rash, vomiting, diarrhea, arthralgia, arthritis, aphthous ulcers, and cervical lymphadenopathy. In some cases the clinical picture of the patient does not fit to one autoinflammatory syndrome because of the digenic inheritance. This may cause to overlap or atypical clinical features or an unexpected response to treatment. Herein we report two cases of hyperimmunoglobulinemia D syndrome that also had MEFV gene mutations and familial Mediterranean fever phenotype.

Keywords: digenic inheritance, familial Mediterranean fever, hyperimmunoglobulinemia D syndrome, periodic fever