Plasma cholinesterase variants in population samples from south-west France.

The results of a study of distribution of plasma cholinesterase types in some Pyrenean groups (south-west of France) are reported. The samples examined were collected in several rural communities. The individuals tested were natives from the different areas. The data show significant differences between the geographic zones. At E1 locus the frequency of Ea1 gene reaches higher values in Luz Saint-Sauveur valley (7.7%). Among Basques and other groups this allele remains in the range of other caucasoid populations. A relatively high frequency of Es1 allele (2.1%) is found in Basques. The Ef1 gene was only found at a low rate in one community. At E2 locus, E+2 frequency is roughly similar to the values observed in Europeans except for Basque, Capcir and Toulouse people who share significantly lower values.