RESULTS: MEFV mutations were identified in 25 of 26 typical FMF patients and in two of 12 patients with atypical manifestations.

Isotopic fractionation of stable carbon isotopes Carbon-13 (13C) and Carbon-12 (12C) refers to the fluctuation in the carbon isotope ratios as a result of natural biochemical processes as a function of their atomic mass (Taylor, 1987).

Variations as such are unrelated to time and natural radioactive decay.

It is common practice in radiocarbon laboratories to correct radiocarbon activities for sample fractionation.

Adolescent, Adult, Base Sequence, Child, Preschool, Cohort Studies, Cytoskeletal Proteins, Familial Mediterranean Fever, Female, Greece, Homozygote, Humans, Male, Middle Aged, Mutation, Nucleic Acid Hybridization, Polymerase Chain Reaction, Proteins, Ribonucleases BACKGROUND: The MEFV gene is responsible for familial Mediterranean fever (FMF).

Several disease associated mutations have been identified.

The range of genetic variation in MEFV in Greek patients has not been determined.

OBJECTIVE: To describe a method that facilitates the routine screening of the entire coding sequence of MEFV (excluding exon 1).

METHODS: The non-isotopic RNase cleavage assay (NIRCA) was optimised and used as a first step screening method to screen exons 2 to 10 of MEFV.

Exons 2 and 10 were analysed separately at DNA level, while exons 3 to 9 were analysed together at c DNA level.