Letete, N.Vaz, DeborahMalishi, P.H.Potgieter, J.J.Rheeder, Paul2025-06-272025-06-272024-01Letete, N., Vaz, D., Malishi, P.H. et al. 2024, 'Recurrent venous thrombosis – an unusual first presentation of autoimmune polyendocrinopathy syndrome type 3B', South African Medical Journal, vol. 114, no. 1, pp. 11-15. https://doi.org/10.7196/SAMJ.2024.v114i1.1477.0256-9574 (print)2078-5135 (online)10.7196/SAMJ.2024.v114i1.1477http://hdl.handle.net/2263/103013A 45-year-old female presented with unprovoked recurrent venous thromboembolism (VTE), in unusual sites, and pancytopenia, posing a complex diagnostic challenge. Work-up for inherited thrombophilia, antiphospholipid syndrome (APLS) and paroxysmal nocturnal haemoglobinuria were unremarkable. Investigations revealed autoimmune thyroid disease, and a mixed iron/vitamin B12 deficiency due to pernicious anaemia and resultant atrophic gastritis. Hyperhomocysteinaemia due to vitamin B12 deficiency was identified as a potential contributor to her recurrent VTE. This case highlights the unusual initial presentation of autoimmune polyendocrinopathy syndrome type 3B (APS-3B) with recurrent thromboembolism, and emphasises the importance of considering hyperhomocysteinaemia in unprovoked and atypical VTE cases.en© 2023 N Letete, D Vaz, P H Malishi, J J Pogieter, P Rheeder. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.HyperhomocysteinemiaAutoimmune polyendocrinopathy syndrome type 3B (APS-3B)Recurrent thrombosisVenous thromboembolism (VTE)Antiphospholipid syndrome (APLS)Article