Growth hormone deficiency in a patient with lysinuric protein intolerance

Lysinuric protein intolerance (LPI; MIM 222700) is a rare, autosomal recessive metabolic disorder caused by mutations in the SLC7A7 gene, which encodes the light chain of the cationic amino acids (CAA) transporter y+. The clinical presentation of LPI includes gastrointestinal symptoms, failure to thrive, episodes of coma, hepatosplenomegaly and osteoporosis. However, other findings have also been reported, and these suggest a multisystem involvement. We report a girl with confirmed LPI who presented with severe short stature that was unresponsive to adequate LPI treatment. The girl was found to have a classic growth hormone deficiency (GHD) and responded well to growth hormone (GH) replacement therapy. While it is not known whether the mechanisms involved in the GHD of our patient are related to LPI, this case suggests that GH/IGF-I axis should be investigated in LPI children with persistent growth failure.