Co‐inheritance of haemoglobin A2′ and beta‐thalassaemia in cis

Abstract

HbA2' is a haematologically silent delta chain variant that elutes in the S-region on high performance liquid chromatography. The major clinical significance of HbA2' is that failure to detect it might lead to failure to recognize beta-thalassaemia minor. Co-inheritance of HbA2' and beta-thalassaemia in cis has been described only once in a family from Suriname. We describe a new case of co-inheritance in cis of HbA2' and beta-thalassaemia in a family from Ghanaian origin with a HbA2' of more than 3%. Molecular investigation revealed the same mutations as in the family from Suriname, suggesting a common origin of both families.

An insight into the suspected HbA2' cases detected by high performance liquid chromatography in Pakistan

“…The levels of HbA2 were found to be higher than those of HbA2' in all cases similar to other published reports [2,6,14,16]. All cases with suspected HbA2' of >2% fell under the category of β-thalassaemia minor if S-window peak was taken into account, which was also consistent with previously published studies [10,14]. Despite the similarities of our HPLC chromatogram analysis with HbA2'studies published earlier, the mutation was absent on genetic analysis.…”

“…Many studies have reported double heterozygotes with HbA2' levels of >2% [2,6] and as high as 3.3% [10]. Blood transfusions in sickle cell disease may dilute HbS to as low as 2.6% [14].…”

“…This genetic disorder has been detected in homozygous [7] and heterozygous states [8], and may also be co-inherited with HbS [9], β-thalassaemia traits [10] and other minor hemoglobinopathies. The clinical significance of identification of HbA2' is in the detection of co-existing β-thalassaemia trait as, in the presence of HbA2', such individual might present with normal HbA2 levels resulting in under diagnosis of thalassaemia minor [11].…”

Heterozygous β‐thalassemia with complete absence of hemoglobin A2 in a Chinese adult

“…Through genetic counseling and the option of prenatal testing, such a couple can opt to bring to term only those pregnancies in which the fetus is unaffected. Elevation of HbA 2 is the most important feature in the detection of heterozygous b-thalassemia, but there are sometimes bthalassemia heterozygotes with normal HbA 2 , compromising the screening effectiveness [1][2][3][4][5]. b-thalassemia with the absence of HbA 2 is very rare.…”