I have been gathering info to get an Irish passport through my grandfather who was an Irish citizen. His birth certificate has one spelling of last name, all documents in the US have a different. My dad changed it back. My grandmother, whom everyone knew as Bridget, is listed as Delia on her marriage certificate and my dad's birth certificate. My mother, who always told me she did not have a middle name until she was confirmed, is listed on her birth certificate with the middle name of Tolenza. I have no idea where that came from.
And in all this research, I can not find any trace of my dad's brother who died as a child. No birth certificate, no death certificate. And the year he would have shown up on a census, 1930, the whole family is missing.