small

My SON was born full term but  only 5 pounds do to a calcified placenta!   At 18 months we had failure to thrive so we test for celic disease!   It came back suggestive for celiac  after the endoscope but not a 100%!  so they ran the gene test and all the blood test again and the all came back normal and the gene test was negative!  We also went to an ENT  to question the toncils because they are very big?  But the Ent said the where big but not wow! I have to say he is not a big eater and not much interest in food!  At 18 months he was 19.6 oz and his two year vist he was 21.3oz  and 3 % for height  I feel he is very small and want to know if  you would suggest to see and endocronolgiest?