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. 2024 Feb 12;5(1):33-38.
doi: 10.1002/jha2.857. eCollection 2024 Feb.

Haemoglobin Ottawa, sickle cell trait and vaso-occlusive crises

Cécile Bobillier  1 , Isabelle Derclaye  2 , Augustin Ferrant  3   4 , Diane Maisin  2
Affiliations

Haemoglobin Ottawa, sickle cell trait and vaso-occlusive crises

Cécile Bobillier et al. EJHaem. .

Abstract

A girl with a sickle cell trait had severe VOCs (vaso-occlusive crises), her father also had a sickle cell trait but mild VOCs, and her mother had no symptoms. Electrophoresis on agarose gel under alkaline conditions showed haemoglobin AS (HbAS) in the girl and in her father, with an S band increased more than expected (46.2% and 41.2% respectively), and a band migrating at C (16.8% and 8.9% respectively) in both. There was a band at S (19.6 %) in her mother. The C band was attributed to a hybrid tetramer with haemoglobin S (HbS) and a Hb variant. A homozygous c.46G>C mutation (Hb Ottawa, the Hb variant) was detected by Sanger sequencing in the girl. Heterozygosity for Hb Ottawa by Sanger sequencing was shown in both the father and the mother. The father, with HbAS and heterozygous for Hb Ottawa, had mild VOCs. Heterozygosity only for Hb Ottawa did not produce any abnormality in the mother. A sister and two brothers of the index patient presented a Hb variant, probably Hb Ottawa, migrating to the S zone (all 20%) at electrophoresis, without HbS. These last three were asymptomatic. We conclude that Hb Ottawa, an α-globin variant, contributes along with haemoglobin S (HbS) to VOC symptoms.

Keywords: haemoglobin variants; sickle cell trait; vaso‐occlusive crises.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

FIGURE 1
FIGURE 1
Haemoglobin electrophoreses on agarose at alkaline pH of the index patient, of her father and of her mother. The quantitative data are in Table 1.
FIGURE 2
FIGURE 2
Haemoglobin capillary electrophoresis of the index patient.
FIGURE 3
FIGURE 3
Family tree, squares are males, circles are females.
See this image and copyright information in PMC

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