Compromising for carrier detection of beta thalassemia based on measurement of HbA2 levels in unusual cases.
BACKGROUND
An increased HbA2 level is the hallmark for identification of β thalassemia carriers. However, in some carriers the level of HbA2 is not typically elevated creating difficulties in making a diagnosis.


METHODS
We describe a family having an affected child referred to us for confirmation of diagnosis of β thalassemia.


RESULTS
The father has a classical β thalassemia trait and the mother showed typical reduced red cell indices with a high RBC count but the HbA2 level was normal (2.4%). On molecular analysis she was a heterozygous carrier having IVS1 nt 5 (G→C) β thalassemia mutation. Further analysis of δ globin gene showed that the reduction in HbA2 was due to the presence of the δ mutation HbA2 Pelendri [CD 141(Leu→Pro, CTG→CCG)].


CONCLUSIONS
The diagnosis of a β thalassemia carrier could have been compromised, and states the importance of comprehensive molecular analysis for accurate diagnosis in couples where one partner has β thalassemia trait.
National Institute of Immunohaematology-ICMR, 13th Floor, New Multistoried Building, K.E.M. Hospital Campus, Parel, Mumbai‐400012, India.
Stacy
S
Colaco
Roshan
R
Colah
K
K
Ghosh
Anita
A
Nadkarni
D000328:Adult; D004909:Erythrocyte Indices; D005190:Family; D005260:Female; D006443:Hemoglobin A2 / Q000032:analysis* / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D055544:beta-Globins / Q000032:analysis* / Q000235:genetics; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000235:genetics*; D055546:delta-Globins / Q000032:analysis* / Q000235:genetics
D055544:beta-Globins; D055546:delta-Globins; D006443:Hemoglobin A2