A total of 1647 cord blood samples (618 of scheduled tribes, 487 of schedul
ed castes and 542 of general castes) of newborns from the Banswara, Bhilwar
a, Chittorgarh, Dungarpur, Sirohi and Udaipur districts of the Aravali hill
y region of Rajasthan were investigated electrophoretically for evidence of
Hb-Bart's (alpha -thalassaemia). Hb-Bart's was encountered in 31 (1.88%) n
eonates constituting 1.8 to 12.6% of their total haemoglobin. Of these, 24
(1.46%) were of alpha -thalassaemia 1 and 7 (0.42%) of alpha -thalassaemia
2. The incidence of alpha -thalassaemia genes varied from 3.07% in the sche
duled tribes, 1.43% in the scheduled castes to 0.77% in the general castes
populations giving an overall incidence of 1.88%. Except Hb-Bart's allele,
no other mutant haemoglobins were observed.