is it unusual in 'normal' children. dd2 had a period of very accelarated growth between 3months till now really, tho is slowing now and back on the 99th percentile. she shot off the charts of 3months old IIRC for height and weight. by the age of 1 she was almost the same size as her 3yr old sister. now at the age od 3 she is the same size and weigth as dd1 who is 6years old. she towers above opther children her age.
she has some autistic traits, food issues(used to vomit a lot, so her weight gaimn was puzzling to say the least), has low muscle tone, and a speech delay. part of me feels all of these behaviours and her growth could be connected, but i cant find anything.