Colour blindness (CB) distribution in the male population of Albanian and Croatian communities of Molise, Italy (with a review of the published Caucasoid CB gene frequencies).

All the secondary school students of the Albanian and Croatian communities of Molise were tested for colour vision. Percent frequencies of red-green colour blindness were 5.91 +/- 1.73 and 7.02 +/- 3.38. These figures are in agreement with those found for Central Italy thus confirming the similarity of these communities with the rest of Italy as described for several other autosomal polymorphisms. The distribution of red-green CB genes in Europe shows that they are slightly more frequent in Northern Europe than in Southern Europe and Northern Africa.