I suspect that in the breastfed babies with kernicterus, that they were not
adequately followed and were not nursing well.  Kernicterus doesn't seem to
occur unless the bili is really high (like over 30-35) in a term baby.  These
kids were likely not nursing well, not getting adequate intake, and not
followed up by a HCP at 2-4 days of age; the bili probably shot up and they
didn't get seen by anyone until it was really high and the kernicterus was
developing.  It would be interesting to look at the cases for these factors.
Linda L. Shaw MD FAAP