Comprehensive analysis of genotype-phenotype correlation in the diagnosis of undifferentiated recurrent fever syndrome in children

Syndrome of undifferentiated recurrent fever (SURF) is a heterogeneous group of autoinflammatory diseases characterized by episodes of systemic inflammation without a confirmed molecular diagnosis and not meeting the criteria for Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Adenopathy (PFAPA) syndrome. Overall, a genetic diagnosis cannot be established in 30-60% of children with recurrent fever syndrome. Aim - to present a clinical case of undifferentiated recurrent fever syndrome in a child triggered by COVID-19 and to raise awareness of this syndrome within the medical community. The clinical case involves a 6-year-old boy experiencing recurrent fever accompanied by arthralgia, fatigue, and significant inflammatory changes in the blood. The first fever episode followed a SARS-CoV-2 infection with pneumonia, and subsequent episodes occurred 2-3 weeks after respiratory infections. Genetic testing revealed a variant of uncertain significance in a heterozygous state in a gene associated with MEFV-like diseases. The absence of sufficient clinical criteria ruled out the diagnosis of Familial Mediterranean fever at this stage, allowing for a diagnosis of undifferentiated recurrent fever syndrome (SURF). Conclusions. Thus, identifying the cause of recurrent fever in children is not always easy or possible. The analysis of genotype-phenotype correlation has an important role in diagnosis in the case of variants of uncertain significance. Viruses, especially SARS-CoV-2, can triggered hyperinflammation. Raising awareness of this syndrome among the medical community will contribute to timely treatment and the prevention of complications. The study was conducted according to the principles of the Helsinki Declaration. Informed consent was obtained from the patient for the study. The author declares no conflict of interest.