Hemoglobin D Los Angeles in Two Caucasian Families: Hemoglobin SD Disease and Hemoglobin D Thalassemia

11 EMOGLOBIN D LOS ANGELES, a2,82121g1m,l (Or D Punjab) is one of I I the more common hemoglobin variants, since it occurs in about 3 per cent of the Sikhs of the Punjab2 and sporadically in other ethnic groups, particularly those that have had considerable contact with India. In electrophoresis and chromatography, this variant is indistinguishable from hemoglobin S; however, it lacks the insolubility of hemoglobin S in the reduced form and, therefore, the ability to cause sickling. It also differs from hemoglobin S on electrophoresis in citrate agar, in which medium it moves like hemoglobin A. Several structurally different hemoglobin variants, such as D Ihadan, a2f328m’ lys.3 share these properties, while still others, such as L, F, and several varieties of G, are similar enough to be easily mistaken for hemoglobin D or for each other. Thus, several hemoglobins originally called D were later found identical with C Philadelphia,4 which, in turn, was first described as Stanleyville J#{149}5 Although a number of reports of sickle cell hemoglobin D disease have appeared, there are only a few in which the hemoglobin D has been precisely identified. Sturgeon et al.#{176} described a family of English, Irish, and American Indian ancestry carrying the genes for hemoglobins S and D Los Angeles.1 Two siblings in this family had inherited a gene for each of these variants and both suffered from a moderate hemolytic anemia. A similar case was described by Smith and Conley,7 and the hemoglobin D Los Angeles was identified by Baglioni.8 In contrast, the simultaneous presence of hemoglobins S and D Ibadan3 in two members of a Nigerian family, was not associated with any disease.