Legg-Calve-Perthes disease in an 8-year old girl with Acrodysostosis type 1 on growth hormone therapy: case report.

Background: Acrodyostosis type 1 (ACRDYS1) is a rare skeletal dysplasia, and sometimes it can be misdiagnosed as pseudohypoparathyroidism type 1A (PHP1A), a subtype of Albright hereditary osteodystrophy (AHO), due to overlapping features. Growth hormone releasing hormone (GHRH) resistance with severe short stature is common in both ACRDYS1 and PHP1A (Emily L. Germain-Lee, et al. J Clin Endocrinol Metab, 88:4059-4069, 2003). Whereas growth hormone (GH) treatment has been studied in patients with PHP1a, the same is not true for the rarer ACRDYS1. Here in we report an adverse orthopedic outcome in a patient with ACRDYS1 with severe short stature treated with growth hormone. Our experience could have implications for the treatment of other patients with this disorder.

Case presentation: We report a case of Legg-Calve-Perthes Disease (LCPD) in an 8-year old female with ACRDYS1 treated with GH. She initially presented with marked short stature (height Z-score - 3.46) with a low normal insulin like growth factor-1 (IGF1) level, and had biochemical evidence of thyrotropin and parathyroid hormone resistance. GH therapy was initiated at 0.35 mg/kg/week leading to increased growth velocity. After 7 months on GH, she developed right knee pain. Radiographic images revealed flattening of her right femoral head consistent with LCPD. GH was discontinued. Six weeks later, radiographs revealed further collapse of the entire femoral head. Her lesion stabilized after 8 months with conservative management and she never resumed GH. Her final adult height is 4'2″ (128 cm).

Conclusion: Patients with ACRDYS1 on GH therapy may be at increased risk of LCPD. This has not been reported in patients with PHP1A treated with GH. Clinicians and families need to be aware of this potential complication when counseling about GH treatment.