ESPE Abstracts

Background: Short stature homeobox-containing (SHOX) gene that strongly affects height. Due to high prevalence of SHOX gene mutations, in all children with unexplained short stature should be investigated to benefit from early growth hormone (GH) treatment. The aim of this clinical study was to determine the rate of SHOX haploinsufficiency in short stature patients and describe their anthropometric measurements.

Methods: Between 2010 and 2017, we evaluated eighty six patients (female: 70, male: 16; aged 4.3–18 years) with a clinical diagnosis of short stature, based on inclusion criteria. Clinical abnormalities were presented for patients with SHOX haploinsufficiency.

Results: Three children (three females) out of 86 patients (70 females) had one copy number of the SHOX gene, and 83 patients had 2 SHOX gene copy numbers, resulting in a rate of 3.6%. 2 of them were were born small for gestational age (SGA). All cases were shorter than the target height, and one of them presented with madelung deformity in clinical examination. Madelung deformity was detected in 3 children, when they were evaluated radiologically. The sitting height/height ratio was found to be within the normal range, while the mesomelia (the diference in arm span and height) was abnormal. Madelung deformity and mesomelic limb shortening were the pronounced clinical features. GH therapy was initiated at a dose of 0.35 mg/kg/week when one individiual was at 7.3 years of age with a height of 107 cm, a height SDS of −3.2, and an annual growth rate of 4.3 cm. Under growth hormone therapy, the growth was 10.2 cm in the first year and 6.2 cm in the second year. The patient responded well to GH treatment for the first two years. Despite the reduction of GH treatment doses, persistent elevated insulin like growth factor (IGF-1) levels cause the treatment to be stopped.

Conclusion: It is likely that the frequency of Madelung deformity would be even higher if patients were evaluated radiologically. Although SHOX alterations and SGA could overlap due to their high prevalence, SHOX mutations must be taken into consideration at children who did not catch up. Since GH treatment was not well tolerated due to persistent elevated IGF-1, it needs long term evaluations of patients with SHOX deficiency.