NEW PUBLISHED ARTICLE: Bobillier et al., 2024

Congratulations to Dr. Bobillier, Dr Ferrant, and colleagues on the publication of their article “Haemoglobin Ottawa, sickle cell trait and vaso‐occlusive crises” in the 𝒆𝑱𝑯𝒂𝒆𝒎 journal. We are delighted to have contributed to the success of this article!

𝐇𝐞𝐦𝐨𝐠𝐥𝐨𝐛𝐢𝐧 (𝐇𝐛) 𝐎𝐭𝐭𝐚𝐰𝐚, also known as Hb Siam, is an α-globin variant caused by a GGT(Gly) to CGT(Arg) mutation in the HBA1 or HBA2 gene. Typically, heterozygous carriers of Hb Ottawa do not exhibit clinical symptoms. However, some 𝐧𝐨𝐧-𝐒 𝐡𝐞𝐦𝐨𝐠𝐥𝐨𝐛𝐢𝐧 𝐯𝐚𝐫𝐢𝐚𝐧𝐭𝐬 can cause 𝐯𝐚𝐬𝐨-𝐨𝐜𝐜𝐥𝐮𝐬𝐢𝐯𝐞 𝐜𝐫𝐢𝐬𝐞𝐬 (𝐕𝐎𝐂𝐬) when combined with the 𝐇𝐛𝐒 𝐦𝐮𝐭𝐚𝐭𝐢𝐨𝐧.

This article reports a patient, with a 𝐬𝐢𝐜𝐤𝐥𝐞 𝐜𝐞𝐥𝐥 trait, who was 𝐡𝐨𝐦𝐨𝐳𝐲𝐠𝐨𝐮𝐬 𝐟𝐨𝐫 𝐇𝐛 𝐎𝐭𝐭𝐚𝐰𝐚 𝐚𝐧𝐝 𝐡𝐞𝐭𝐞𝐫𝐨𝐳𝐲𝐠𝐨𝐮𝐬 𝐟𝐨𝐫 𝐇𝐛𝐒, experiencing severe VOCs. Her father, heterozygous for both Hb Ottawa and HbS, had mild VOCs, while her mother, heterozygous for Hb Ottawa, was asymptomatic. 𝐀𝐝𝐯𝐚𝐧𝐜𝐞𝐝 𝐝𝐢𝐚𝐠𝐧𝐨𝐬𝐭𝐢𝐜 𝐦𝐞𝐭𝐡𝐨𝐝𝐬 like capillary electrophoresis and DNA sequencing were used for diagnosis. The patient experienced 𝐟𝐫𝐞𝐪𝐮𝐞𝐧𝐭 𝐕𝐎𝐂𝐬 since early childhood, which 𝐰𝐞𝐫𝐞 𝐚𝐥𝐥𝐞𝐯𝐢𝐚𝐭𝐞𝐝 somewhat by 𝐡𝐲𝐝𝐫𝐨𝐱𝐲𝐜𝐚𝐫𝐛𝐚𝐦𝐢𝐝𝐞 𝐭𝐫𝐞𝐚𝐭𝐦𝐞𝐧𝐭.

This case is the first to report severe VOCs in a patient homozygous for Hb Ottawa and heterozygous for HbS, highlighting the 𝐧𝐞𝐞𝐝 𝐟𝐨𝐫 𝐚𝐝𝐯𝐚𝐧𝐜𝐞𝐝 𝐝𝐢𝐚𝐠𝐧𝐨𝐬𝐭𝐢𝐜 𝐭𝐨𝐨𝐥𝐬 and 𝐠𝐞𝐧𝐞𝐭𝐢𝐜 𝐜𝐨𝐮𝐧𝐬𝐞𝐥𝐢𝐧𝐠 𝐟𝐨𝐫 𝐟𝐚𝐦𝐢𝐥𝐢𝐞𝐬 with such hemoglobin variants. Further research is required to understand the interaction between Hb Ottawa and HbS in causing VOCs.