Bone Abstracts

Background: Osteopetrosis (OP) is a bone disease which is characterized by increased bone density. Autosomal dominant osteopetrosis type II (ADO II, also called Albers-Schönberg disease) is the most common type and it is caused by heterozygous mutations in the chloride channel 7 (CLCN7) gene.

Presenting problem: To present a patient with known medical and family history of osteopetrosis, who was diagnosed with Growth Hormone (GH) deficiency and was treated with recombinant growth hormone (rGH), which resulted in acceleration of growth velocity and attainment of final height within normal range.

Clinical management: A 12 and 7/12 years old male adolescent was referred because of short stature and deceleration of growth rate. He was the product of an uneventful full-term pregnancy with BW 3350 g and BL 52 cm. The patient was diagnosed in Canada with autosomal dominant osteopetrosis type II. There was also a positive family history of the disease for his father and his brother. As his height was- below the 3rd percentile (−2 S.D.) and IGF-I levels low, growth hormone (GH) stimulation tests were performed and GH deficiency was diagnosed on the basis of a glucagon and clonidine stimulated GH peak below 5 ng/ml. Magnetic Resonance Imaging (MRI) of the pituitary gland was normal. Treatment with rGH was initiated at a dose of 200 μg/kg with a prompt response of growth velocity acceleration (6.6 cm/year), faster than expected according to the growth rate predicting program (igrow). He continued therapy for five years, until he reached 17 and 9/12 years of age, when rGH treatment was discontinued. His final height was within the normal range for the age and sex, 169 centimeters (10th percentile). There were no complications during treatment or during follow up after discontinuation.

Discussion: To our knowledge this is the first report of a patient with osteopetrosis and GH deficiency treated with growth hormone. Growth hormone therapy can be beneficial for patients with GH deficiency and osteopetrosis. As osteopetrosis is a very rare condition further experience is needed.

Disclosure: The authors declared no competing interests.