We found that the HbG-San Jose mutation was associated with haplotype VII [
---- / - +] in four families from Campania and in one family from Calabria,
and with the haplotype IV [+ - + + / - +] in two families from Eastern Sic
ily. These results support the hypothesis that the mutation had a unique or
igin in Southern Italy and a subsequent recombination event gave rise to th
e background heterogeneity.