Mark, a 2 year old child, is brought to the pediatrician by his parents for a routine visit. Mark is generally a happy child who fusses frequently, but is consolable. He feeds regularly and appropriately, although he has always been small for his age. When taking a developmental history you learn that Mark currently can sit up on his own for 10 minutes at a time, but does not walk, squat or climb stairs. While he can make a pincer grasp, he does not take off his shoes nor carry objects. His vocabulary includes about 10 words, and he is not yet putting words together into phrases. His parents recall having routine prenatal genetic testing (results normal) and intermittent prenatal care visits. They remember that he was consistently small for age on prenatal ultrasound, and that at 8 months he was delivered without complications. When examining the child you notice some dysmorphic facial features. Specifically, the ridge between his nose and upper lip is uncharacteristically smooth, he has a thin upper lip, and his eyes appear wide set. His head circumference, height and weight are all 9% expected for sex and age.
