Growth hormone treatment of skeletal dysplasia

Abstract

It seems that recombinant human growth hormone (rhGH) therapy can lead to increased growth in just about any child with (or without) chronic disease. An exception to this has been one of the more common skeletal dysplasias achondroplasia. Attempts at achieving enhanced growth in children with this disorder have not been successful.Achondroplasia is caused by a mutation in the FDFR3 gene. There is a phenotypically very similar condition, hypochrondroplasia, which is actually associated with a different mutation in this same gene. In this issue of The Journal, Rothenbuhler et al provide an interim report of a trial of rhGH in 6 children with hypochondroplasia. This is an important report for a couple of reasons. First of all, the authors used a dosing regimen for the rhGH that was titrated to achieve preset goal levels of insulin-like growth factor 1 in each patient. Unlike the situation with achondroplasia, all of these children had improved statural growth and improvement in body proportion during this first period of treatment. The second important take-home message from this report is the potential need for mutation analysis in children with suspected achondroplasia. Because the disorder may not be differentiated from hypochondroplasia clinically, and the two disorders appear to differ in their responsiveness to growth hormone, making the correct diagnosis may be extremely important for the child's ultimate outcome.Article page 849▶ It seems that recombinant human growth hormone (rhGH) therapy can lead to increased growth in just about any child with (or without) chronic disease. An exception to this has been one of the more common skeletal dysplasias achondroplasia. Attempts at achieving enhanced growth in children with this disorder have not been successful. Achondroplasia is caused by a mutation in the FDFR3 gene. There is a phenotypically very similar condition, hypochrondroplasia, which is actually associated with a different mutation in this same gene. In this issue of The Journal, Rothenbuhler et al provide an interim report of a trial of rhGH in 6 children with hypochondroplasia. This is an important report for a couple of reasons. First of all, the authors used a dosing regimen for the rhGH that was titrated to achieve preset goal levels of insulin-like growth factor 1 in each patient. Unlike the situation with achondroplasia, all of these children had improved statural growth and improvement in body proportion during this first period of treatment. The second important take-home message from this report is the potential need for mutation analysis in children with suspected achondroplasia. Because the disorder may not be differentiated from hypochondroplasia clinically, and the two disorders appear to differ in their responsiveness to growth hormone, making the correct diagnosis may be extremely important for the child's ultimate outcome. Article page 849▶