[A new PiN mutation at the Pi locus in human populations].

By a bidimensional immuno-isofocalisation electrophoresis method a new PiN allel was revealed in 365 samples collected in a Caucasoïd population from a Central Pyrenees Valley (Les Baronnies). Its high frequency (0,151) contributes to the decrease of the PiM one. The different NS, MN and NN phenotypes were formerly classed respectively as MS and MM phenotypes. PiN allel seems to be widely distributed in Mediterranean populations.