J.J.
Has your dr looked into sleep apnea? I remember reading that there's a coorelation between low birth weight and sleep apnea...
Good luck to you and your family in your quest for answers....it's a hard place to be....knowing that there may be something needing medical attention, but not knowing yet what it is or how to proceed. Trust your mother's intuition and be persistant with the doctors. You're in my thoughts.
~J. J