The delta 32 deletion does not bestow shorten life expectancy. That one very small study was retracted 2/2 obvious calculation bias. And I understand your skepticism but I may offer a thought to consider. What we often feel is incredible and "hard to believe" lies more with our own unconscious assumptions which underlie our perception of reality then reality itself. Remove any such assumptions (in practice this is virtually impossible) and what preciously seemed like a miracle becomes merely a new level of understanding.