Diagnostic evaluation of short children with height 3 SD or more below the mean

Most children who are more than 2 SD below the mean in height (less than third percentile) have no definable cause and are considered short-normal, but for children who are 3 SD below the mean (the lowest 0.13%), the prevalence of organic disease is known to be considerably greater. To better define the frequency of different diagnoses in this subgroup and to identify useful clinical findings, we reviewed the charts of all children referred for growth evaluation over a 10-year period who were > or = -3 SD in height, > 2 years old, and prepubertal. Of 60 patients (36 males and 24 females), 22% had constitutional growth delay (CGD), 23% had growth hormone deficiency (GHD), 13% had Turner syndrome, and 22% had various forms of primary growth failure (mostly associated with intrauterine growth retardation). Eight percent had very slow growth over a prolonged period but no definable cause, and 12% did not fall into any of the above groups. For differentiating GHD from CGD, a subnormal height velocity for age during a 4- to 12-month observation period, a low insulin-like growth factor-1/somatomedin C (IGF-1/Sm-C), and low total or free T4, with normal TSH, were all highly predictive of a diagnosis of GHD.