Clinical and molecular evaluation of children with Familial Mediterranean Fever and their siblings: A single center study in Upper Egypt.

Background: Familial Mediterranean Fever (FMF) represents the most prevalent monogenic auto inflammatory disease, with its etiology primarily attributed to mutations within the MEFV gene.
Objective: To characterize the clinical patterns of FMF, identify common gene mutations, and monitor the response to therapy in children suffering from FMF and their siblings.
Patients and Methods: The Pediatric Department of Sohag University Hospital served as the setting for this one-year prospective observational study (August 2022 - August 2023). Children and their siblings, all diagnosed with Familial Mediterranean Fever (FMF) based on Tel Hashomer criteria, were included in the research.
Results: A total of 99 children were included (85 children already diagnosed and 14 of their siblings). Patients were divided into 3 groups:  negative- gene group(n=16), homozygous group(n=30) and heterozygous group(n=53). Fever and abdominal pain were the most common presentations in 96.9% and 93.9% of patients, respectively. Homozygous group had significantly higher severity score than other groups (p value=0.048). Response to colchicine therapy was complete in 82.8% of patients, incomplete in 16.1% and no response in one patient. The most frequent mutations were M-694-V, M-694I, E-148-Q and V-726-A reported in 30.12%,25.30%,15.66% and 10.84%. of patients, respectively.   
Conclusion: In our cohort study, fever and abdominal pain were the most common presentations of FMF and the most frequent mutations were M-694-V, M-694I, E-148-Q and V-726-A. Most of newly diagnosed patients had the same genetic mutation as their siblings. Patients in homozygous group had higher severity score than other patients. Most patients achieved complete response to therapy with favourable response noted with E148Q mutations followed by M694V mutations.