Children often present to pediatricians and pediatric endocrinologists because of abnormal body growth, including both childhood growth failure and, less commonly, overgrowth. Sometimes the cause is evident, for example, growth hormone deficiency for growth failure and growth hormone excess for overgrowth. In other children, the etiology remains unknown despite extensive evaluation, resulting in the unhelpful diagnosis of severe idiopathic short stature or tall stature. These conditions are quite heterogeneous, including children with isolated growth disorders and others who also have other abnormalities such as developmental delay or a constellation of congenital anomalies (syndromic growth disorders). Some cases of severe growth disorders have a polygenic inheritance while others appear to be inherited as a monogenic trait recessive, dominant or X-linked. Because of recent advances in DNA sequencing technology, it is now feasible to sequence the exome (portion of the genome that encodes gene exons) in families with monogenic disorders and thereby determine the underlying molecular etiology.