ESPE Abstracts

Background: Idiopathic short stature (ISS) is a term used to describe a group of short children for whom no precise etiology has been identified. Many children - if not the majority - referred with short stature are designated ISS. We report the case of a child with idiopathic short stature receiving off-label therapy with recombinant human growth hormone (rhGH). GH treatment showed significantly good results at short and long-term follow-up.

Case Report: A five-year-old male presented to our hospital with short stature. He was term-born, weighed 3400 g (47 percentile), and 50 cm long (>30th percentile). On physical examination, his height 97 cm (-2.7 SD), mean parental height 170 cm (-1 SD) with slow growth velocity (<-1 SD), no dysmorphic features, his body proportions are normal, no significant medical problems or skeletal malformations were reported. Blood tests showed normal thyroid hormones, normal level of IGF-I SDS (-0.9±0.6) and of insulin-like growth factor binding protein 3 (IGFBP-3) and celiac disease was excluded. His bone age was one year delay compared to chronological age (According to the standards of Greulich and Pyle). The growth hormone stimulation test (GHST) showed a normal peak GH level (12 μg/L). Chromosomal studies revealed a karyotype of 46, XY and SHOXgene mutational analysis was negative. Follow-up showed no change in auxological parameters. At seven-year-old, a second GHST showed a peak GH of 11μg/L. Treatment with recombinant human growth hormone (rhGH) was started, resulting in a significant improvement in growth velocity in the first year, up to 7 cm/year (>95-97th centile), with a significant increase in IGF-I and normal progression of bone age. Serum IGF-I levels were measured every six months together with auxological parameters. Significant results of GH therapy were shown during follow-up growth height SDS improved from −2.7 at baseline to −1.8 at 8 years and −1.4 at 10 years.

Conclusion: Idiopathic short stature (ISS) is estimated to be present in about 2 to 3% of children-generally healthy children who are much shorter than normal for no apparent biological or physiological reasons. According to our national guidelines, no strict indication to GHT is reported. However, GHT has been found to be very effective in increasing linear growth in our patient. This case shows that normal height and growth rate in childhood can be achieved by optimizing personalized growth hormone treatment according to ISS phenotypes.