ESPE Abstracts

Background: Based on growth screening rules, severe short stature (i.e. height SDS less than -3), at the age of more than 3 years, warrants diagnostic evaluation in specialized health care. In the absence of apparent underlying cause, targeted and eventually untargeted genetic studies have been proposed. However, the etiology of short stature at the severe end of the spectrum is poorly characterized.

Methods: We identified all subjects with height SDS < -3, after the age of three years, from our hospital district (Helsinki University Central Hospital, population of 1.2 million) growth database. Subjects with erroneous or missing data, born prior to 1990, or place of residence outside the hospital district were excluded. Total of 821 subjects (394 females, 427 males) fulfilled our inclusion criteria; we reviewed their medical records, growth data (22129 height measurements), and report their underlying diagnoses.

Results: A pathological cause for short stature (i.e. condition other than ISS) was diagnosed in and 287 (73 %) girls and 284 (67 %) boys (P=NS). The five most frequent causes in girls and boys were syndromes (26 % vs. 13%, P<0.001), ISS (23 % vs. 30 %, P<0.05), disorders in organ systems (15 % vs. 16 %, P=NS), SGA without catch-up growth (9 % in both sexes), and defects in the GH-IGF-I system (8 % vs. 14%, P<0.01). The probability of growth-related pathology was increased with the deviation from the target height, and with the shorter SD score. For example, in patients with the shortest measured height <- 4 SDS, skeletal dysplasia or a syndromic cause was identified in half of the cases, whereas ISS was rare (<7%).

Conclusions: By applying the cut-off of -3 SDS after the age of three years, severe short stature was equally frequent in girls and boys, and pathological causes were found in more than two-thirds in both sexes. Pathological causes were particularly frequent in the shortest subjects and in those with higher target height. Given that our hospital serves as the primary referral center for the region's well-child and school primary health care services, our results are expected to represent the spectrum of growth disorders at the population level.