A 2 year old girl is brought in for evaluation of short stature. Her height centiles have been inadequate from 9 months of age.

She was born at term with a weight of 3.35 kg and a length of 45 cm, with no perinatal or postnatal complications. Her medical history is unremarkable, and she is developmentally normal except for a mild delay in gross motor milestones. Her parents are first cousins, and are of normal heights.

She was investigated for short stature 3 months ago; her diet was found to be adequate, while her hematological indices and renal, thyroid, and liver function tests were normal. However, her bone age was found to be only 12 months.