Good question, but no: There was in fact no dyslexia involved...
"International Organization for Standardization" would have different abbreviations in different languages ("IOS" in English, "OIN" in French for Organisation internationale de normalisation), It was decided to use a word derived from the Greek isos, meaning "equal". Thus, whatever the country, whatever the language, the short form of the organization's name is always ISO.
/Claes