Hb Q(India) and its interaction with beta-thalassaemia: a study of 64 cases from India.
Haemoglobin Q (Hb Q), a relatively uncommon alpha-chain structural Hb variant, has been reported either in the heterozygous state or interacting with beta-thalassaemia. Individuals inheriting Hb Q generally are asymptomatic and are diagnosed by chance during population screening or as a part of a family study. This paper represents the first large study from India of 64 cases of Hb Q, documenting the haematological and molecular findings on 36 cases of Hb Q trait, 22 of Hb Q beta-thalassaemia trait and three of Hb Q beta-thalassaemia major, as well as a family of Hb Q homozygous cases. Hb Q is detected by Hb electrophoresis and chromatography. Hb Q levels in homozygous cases ranged from 32% to 35%, while in Hb Q heterozygotes the level was 20%. When there was an interaction of beta-thalassaemia heterozygotes the level was 14%, and in interacting beta-thalassaemia homozygotes the levels ranged from 7% to 9%. beta-thalassaemia mutations were characterised in cases showing elevated Hb A2 levels, which were markedly reduced in the majority of cases in which beta-thalassaemia was absent. Hb Q is rare and not a single homozygous case has been reported. However, Hb Q disease showed wide variation in clinical and haematological presentation in the same family.
Phanasgaonkar
S
S
Institute of Immunohaematology, K.E.M. Hospital, Parel, Mumbai, India.
Colah
R
R
Ghosh
K
K
Mohanty
D
D
Gupte
S
S
D014644:Genetic Variation; D006455:Hemoglobins, Abnormal / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007194:India; D010375:Pedigree; D010641:Phenotype; D013789:Thalassemia / Q000235:genetics / Q000378:metabolism; D017086:beta-Thalassemia / Q000235:genetics* / Q000378:metabolism
D006455:Hemoglobins, Abnormal; C048600:hemoglobin Q India