G6PD and G6PD deficiency: Causal attribution may be challenging when unfractionated heparin is coadministered, and the relevance of glucose-6-phosphate dehydrogenase (G6PD) deficiency remains uncertain.<h4>Case presentation</h4>A 34-year-old man with known G6PD deficiency presented with an inferior ST-segment elevation myocardial infarction and underwent primary PCI.