Hb S, Hb G-Philadelphia and alpha-thalassemia-2 in a Black family.
A Black family is described in which Hb S, Hb G-Philadelphia and alpha-thalassemia-2 determinants occurred in different combinations. The propositus was a healthy fullterm neonate who had 46% Hb G-Philadelphia and about 5% Hb Bart's in cord blood together with a relative microcytosis (MCV = 85 fl) and hypochromia (MCH = 28 pg). This is consistent with a diagnosis of Hb G-Philadelphia trait in association with a homozygous alpha-thalassemia-2 (alpha 0 alpha/alpha 0 alpha G; beta A/beta A). The mother and another son also had Hb G-Philadelphia in association with Hb S trait but with 37% Hb G-Philadelphia and with 39% Hb S. Hemotological and biosynthetic studies confirm the assignment of the alpha alpha/alpha 0 alpha G; beta A/beta S genotype in both and that of the alpha alpha/alpha 0 alpha; beta A/beta A genotype in the father. Despite this evidence for a moderate alpha chain deficiency in the propositus, the biosynthetic alpha/non-alpha value in the neonatal period was a high 1.2. Similar values were observed in 8 control cord blood samples if the incubation was not delayed longer than 3 hours after collection (alpha/non-alpha = 1.28 +/- 0.14). When the propositus was studied again, but at six months of age, the proportion of Hb G-Philadelphia in peripheral blood was unchanged, a marked microcytosis and hypochromia were observed, and a distinct deficiency of alpha chain synthesis (alpha/non-alpha = 0.56) was present.
D000328:Adult; D000755:Anemia, Sickle Cell / Q000235:genetics; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006453:Hemoglobinopathies / Q000097:blood / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000096:biosynthesis; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013789:Thalassemia / Q000235:genetics
D006455:Hemoglobins, Abnormal