Familial Mediterranean fever is a recessive autoinflammatory disease that is 
frequent in Armenians, Jews, Arabs, and Turks. The MEFV gene is responsible for 
this disease. We looked for MEFV gene variations (polymorphism and mutations) in 
a population that resides in Central Anatolia, Turkey. DNA was extracted from 
peripheral blood leukocytes of 802 familial Mediterranean fever patients. The 
DNA sequence data were examined for approximately 150 different mutations and 
polymorphisms, including single nucleotide polymorphisms in different exons of 
the MEFV gene. The male:female ratio of these patients was 1.44:1. Mutations 
were detected in 48.1% of the patients; 7.5% were homozygous, 11.1% were 
compound heterozygous and 31.5% had only one identifiable mutant allele. No 
mutations were detected in 51.9% of the patients. The main clinical 
characteristics of the patients were: abdominal pain in 20.6%, arthritis in 
22.9% and amyloidosis in 4.6%. Sixty-six percent of patients had a family 
history of familial Mediterranean fever; 19.4% of the patients were found to 
have parental consanguinity. We conclude that the genetics of familial 
Mediterranean fever is more complex than has previously been reported; 
heterozygous patients presenting a severe phenotype should be further analyzed 
for less common secondary MEFV mutations, using gene sequencing.