==== Front Am J Hematol Am J Hematol 10.1002/(ISSN)1096-8652 AJH American Journal of Hematology 0361-8609 1096-8652 John Wiley & Sons, Inc. Hoboken, USA 36030404 10.1002/ajh.26704 AJH26704 Clinical Pearls in Blood Diseases Clinical Pearls in Blood Diseases Morphology Update G6PD deficiency in patients identified as female Bain et al. Bain Barbara J. https://orcid.org/0000-0003-3077-4579 1 2 b.bain@imperial.ac.uk Myburgh Jane 1 Lund Kirstin 3 Chaidos Aristeidis 4 1 Blood Sciences, Imperial College Healthcare NHS Trust St Mary's Hospital London UK 2 Centre for Haematology, St Mary's Hospital Campus of Imperial College Faculty of Medicine St Mary's Hospital London UK 3 Department of Paediatric Haematology St Mary's Hospital London UK 4 Hugh & Josseline Langmuir Centre for Myeloma Research, Centre for Haematology, Department of Immunology and Inflammation, Imperial College London Hammersmith Hospital London UK * Correspondence Barbara J. Bain, Blood Sciences, St Mary's Hospital, Praed Street, London, W2 1NY, United Kingdom. Email: b.bain@imperial.ac.uk 12 9 2022 2 2023 98 2 10.1002/ajh.v98.2 359360 22 8 2022 23 8 2022 © 2022 The Authors. American Journal of Hematology published by Wiley Periodicals LLC. https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. source-schema-version-number2.0 cover-dateFebruary 2023 details-of-publishers-convertorConverter:WILEY_ML3GV2_TO_JATSPMC version:6.2.7 mode:remove_FC converted:11.04.2023 Bain BJ , Myburgh J , Lund K , Chaidos A . G6PD deficiency in patients identified as female. Am J Hematol. 2023;98 (2 ):359‐360. doi:10.1002/ajh.26704 36030404 ==== Body pmc Symptomatic glucose‐6‐phosphate dehydrogenase (G6PD) deficiency, being X‐linked, is seen particularly in males. Cases in female homozygotes are uncommon but well recognized. Symptomatic hemolysis can also occur in female heterozygotes since cells that express the defective gene are prone to lysis. Since lyonization can be unbalanced, hemolysis is sometimes severe. There are also other uncommon circumstances when G6PD deficiency leads to clinically apparent hemolysis in females or patients identified as female. Recognition of this possibility requires close liaison between clinical and laboratory staff. The left image (both images ×100 objective) is the blood film of a 3‐year‐old Syrian girl who presented with acute hemolysis 3 days after eating falafel. Her blood count showed a hemoglobin concentration (Hb) of 74 g/L and an MCHC of 375 g/L. The image shows irregularly contracted cells and numerous “blister cells” or “hemighosts.” In addition, there is one cell that is virtually devoid of hemoglobin, a “ghost cell.” G6PD was 2.2 U/gHb (normal range 6.3–11.2). The increased MCHC reflects the presence of numerous irregularly contracted cells. Because the hemolysis was unusually severe for a female, DNA analysis was performed. This showed homozygosity for G6PD c.653C>T; p.Ser218Phe, also known as G6PD Mediterranean. The patient's 5‐year‐old brother presented simultaneously with an Hb of 70 g/L and a G6PD assay of 2 U/gHb. The patient's father, who was known to be G6PD deficient, had milder haemolysis. Falafel are traditional made with chick peas but are sometimes made with fava beans (broad beans) or with a mixture of the two. Patients and physicians may not be aware of this possibility. The right image is of the blood film of an adult South Asian patient identified in hospital records as “female,” who presented with fever and symptomatic anemia. It shows similar features to the first patient with numerous irregularly contracted cells and blister cells. In addition, Heinz bodies are apparent, precipitated within the otherwise empty area of cytoplasm within blister cells. Hb was 70 g/L. A G6PD assay confirmed deficiency. Again, the hemolysis was unusually severe for a female and further enquiries were made. It was discovered that the patient was a trans female, genetically male but choosing to identify in medical records as female. Other circumstances in which G6PD deficiency leading to symptomatic hemolysis of unexpected severity in a female that have been reported include Turner syndrome (female patients with a single X chromosome) and females who have been transplanted with bone marrow from a G6PD‐deficient male. As it becomes possible in various jurisdictions for trans persons to legally change their gender in official records, diagnostic conundrums are likely to arise. Close liaison between clinical and laboratory staff is essential for these patients and also for those who have had a bone marrow transplant that is unknown to the laboratory as it was performed in another hospital. CONFLICT OF INTEREST The authors declare no conflict of interest. DATA AVAILABILITY STATEMENT Data availability statement is not applicable.