α-THALASSEMIA DOES NOT SIGNIFICANTLY CONTRIBUTE TO THE LOW MCV LEVEL OF Hb C TRAIT

Laboratory parameters provided by Advia 2120 analyser identify structural haemoglobinopathy carriers and discriminate between Hb S trait and Hb C trait

“…No differences in MCV were found between HbAC and HbAA, both of them without α-TT, in the study of Couto et al 20. However, Silva et al hypothesised that α-TT does not significantly contribute to the microcytosis in HbAC individuals, and the presence of HbC may itself cause a reduction in the RBC size 21. A slightly higher degree of microcytosis in HbAS and/or HbAC compared with HbAA has been described by many other authors, but the main cause for their lower MCV was not clear since analysis of the α genes was not performed and the iron status was not assessed 23–25…”

“…Hb A 2 levels, Hb F levels and the percentage of variant Hb were determined by HPLC in the HA-8160 analyser (Menarini Diagnostics, Florence, Italy). According to published studies, subjects with a percentage of variant Hb <35% (for HbS)16 27 or <37% (for HbC)20 21 were considered to have coexistent α-thalassaemia (α-TT). Subjects with a percentage of HbS <35% or percentage of HbC <37% and also ferritin levels <20 ng/mL and/or TSI <20% were considered to have both coexistent iron deficiency and α-TT.…”

Hemoglobina C em homozigose e interação com talassemia beta

“…1 Talassemia alfa pode estar associada ao traço ou a homozigotos, e isso reduz a concentração da C, podendo causar confusão diagnóstica. 9,10 Retinopatia e hematúria têm sido descritos no traço C. 11,12 Poderá haver interação também com hemoglobina Lepore, talassemia delta-beta e persistência hereditária da Hb Fetal. A raridade do diagnóstico C homozigoto e C talassemia beta nos pacientes portadores de hemoglobinopatias nos alertou para a necessidade de se conhecer melhor e estudar aspectos clínicos e hematológicos dos casos dessa mutação em homozigose e na interação com a talassemia beta (HbCC e Cβ talassemia) no ambulatório de anemias do Centro Regional de Hematologia e Hemoterapia de Ribeirão Preto, SP.…”

Microcytosis in patients with haemoglobin C trait: is α‐thalassaemia trait to blame?

“…1 The βglobin Glu6Lys substitution decreases HbC solubility, causing sickle cell disease when co-inherited with haemoglobin S. However, HbC trait is asymptomatic and displays normal haemoglobin concentration. While some have reported mean corpuscular volume (MCV) in the lower normal range, [2][3][4] others report microcytosis, [5][6][7] typically attributed to iron deficiency and/or co-inheritance of α-thalassaemia trait, as both are prevalent in this population. It thus remains uncertain whether HbC trait in isolation causes microcytosis.…”