Spectrum of Variants and Genotypes among Clinically Diagnosed FMF Patients from Southern Lebanon.

Familial Mediterranean Fever (FMF) is an autosomal recessive auto-inflammatory disease characterized by pathogenic variants in the gene, with allele frequencies greatly varying between countries, populations and ethnic groups. In order to analyze the spectrum of variants and genotypes among clinically diagnosed FMF patients from South Lebanon, data were collected from 332 participants and 23 variants were screened using a Real-Time PCR Kit. The mean age at symptom onset was 17.31 ± 13.82 years. The most prevalent symptoms were abdominal pain, fever and myalgia. molecular analysis showed that 111 patients (63.79%) were heterozygous, 16 (9.20%) were homozygous, and 47 (27.01%) carried two variants or more. E148Q was the most encountered variant among heterozygous subjects. E148Q/M694V was the most frequent in the compound heterozygous/complex genotype group, while M694I was the most common among homozygous patients. Regarding allele frequencies, M694V was the most common variant (20.7%), followed by E148Q (17.1%), V726A (15.7%) and M694I (13.2%). The high percentage of heterozygous patients clinically diagnosed as FMF highlights the pseudo-dominant transmission of the disease in Lebanon and emphasizes the importance of molecular testing for a more accurate diagnosis and better management and treatment of FMF.