The MEFV gene involved in familial Mediterranean fever was recently cloned and four distinct sequence alterations (M680I, M694V, M6941 and V726A) were identified at the 3'-most exon. We genotyped 170 unrelated FMF patients from various ethnic groups in Israel and found that mutation M694V predominates in North African Jews, that mutation V726A is common in Jewish patients other than North African Jews and that all four mutations occur in patients of Arabian origin, namely, Moslems, Christians and Druze. Since these four distinct sequence alterations seem to account for the majority of mutations identified in FMF patients from the middle east, we have devised a simple protocol using PCR mediated site directed mutagenesis or naturally occurring recognition sites to scan for these mutations.