454 CORRADO BAGLIONI 



acteristic of thalassemia and one parent is found to be affected by 

 thalassemia minor. The thalassemia in the Hb-H carrier and in the 

 affected parent is of the non-increased Hb-Aa type (Silvestroni et al., 

 in the infants, when Hb-A substitutes Hb-F. The presence of Hb-Bart's 

 in cord blood has been attributed in these cases to heterozygosity for a 

 chain thalassemic genes. These genes may manifest themselves with 

 ever, of no use for the carriers; its oxygen affinity is far too high to 

 permit release of oxygen to the tissues (Benesch et al., 1961). 



Hb-H is not inherited in a Mendelian way (Motulsky, 1956). The 

 parent affected by thalassemia does not show, in the majority of the 

 cases reported in the literature, any Hb-H; transmission from father to 

 son has been reported (Fessas, 1959). Only a small fraction of the 

 individuals presumably affected by a thalassemia are Hb-H carriers. 

 The unpredictable appearance of Hb-H may be related to other factors, 

 which affect the eiythropoiesis or the rate of destruction of red cells in 

 subjects affected by a thalassemia. The amount of Hb-H is quite vari- 

 able in the carriers and undetected amounts of this hemoglobin may 

 be present in individuals classified as normal. The presence of Hb-H 

 may also be caused by the interaction of two abnormal genes, one of 

 which has a very low expressivity and does not ajipreciably depress 

 hemoglobin synthesis in heterozygotes. 



2. Hb-Bart's 



Fessas and Papaspyrou (1957) and Ager and Lehmann (1958) 

 reported an abnormal hemoglobin in infants with a thalassemic blood 

 picture. This hemoglobin has been designated Hb-Bart's. Hunt and 

 Lehmann (1959) have fingerprinted Hb-Bart's and have shown that 

 tliis hemoglobin is made up of y'" chains only; Hb-Bart's seems to have 

 the structural fornnila 74'''. Like Hb-H, Hb-Bart's has been found to 

 be associated with a thalassemia. Baglioni et al. (1961) have shown the 

 presence of Hb-Bart's in a newborn, who inherited a thalassemic gene 

 interacting in his mother witli an a chain abnormality (Hb-I = a2 ^2^^) 

 and thought to be an a^^' gene. Recent studies on the hemoglobins of 

 newborns have shown that Hb-Bart's occurs with high frequency among 

 newborns in some populations. Vella (1959) observed a fast abnormal 

 component, presumably identical with Hb-Bart's, in 4% of the cord 

 bloods of Cliinese newborns. Hcndi'icksc et al. (1960) have found a 

 10% frequency of Hb-Bart's in cord bloods of Nigerian newborns. Sim- 

 ilar findings for the Negro population of the United States have been 

 reported by Minnich et al. (1962) and by Weatherall and Boyer (1961). 

 Lie-Injo (1961) has reported the occurrence of Hb-Bart's in Indonesians, 

 Malays, and Chinese. The high fi-criucnoe with wliich Hb-Bart's has been 



