The story
From hypo- + splen- + -ism. Etymology tree Proto-Indo-European *upó Ancient Greek ῠ̔πό (hŭpó) Ancient Greek ὑπο- (hupo-)der. English hypo- Ancient Greek σπλήν (splḗn)der. English spleno- English -ism English hyposplenism
Etymology from Wiktionary, CC BY-SA 4.0.