Effect of Growth Hormone treatment on Height Velocity of Children with Pycnodysotosis

Objective: Pycnodysostosis is a rare autosomal recessive osteochondrodysplasia resulting from osteoclast dysfunction. Growth hormone (GH) secretion impairment and low insulin growth factor 1 (IGF-I) concentrations have been reported in these patients. The present study aims to describe GH effect on linear growth of eight children with pycnodysostosis. Methods: This study was conducted on 8 children suffering from pycnodysostosis. After evaluating systemic diseases, adrenal insufficiency, and hypothyroidism, bone age, height standard deviation score (HtSDS), body mass index (BMI), and some demographical characteristics were measured. To measure the serum GH, we performed two clonidine tests in two different days with an interval of 24 hours. With initiation of the trial, human GH was injected subcutaneously once a day 6 days a week for a period of 1.5 years. The patients were followed up every 3 months to document their height and BMI until 6 months after the end of the treatment. Findings: All of the patients had growth hormone deficiency. HtSDS at the first visit continued to decrease during the 6 months before starting the treatment; however, HtSDS started to increase after beginning of GH administration. This value again declined after discontinuing the GH. Overall, the mean of linear growth was improved after GH administration in the patients. Conclusion: The present clinical study revealed that GH administration had a positive impact on the linear growth of the children suffering from pycnodysostosis.