GLS and Global developmental delay: One patient carried a S482C mutation and suffered from infantile cataract, skin lesions, and profound developmental delay.16 The second patient carried a H461L mutation and suffered from epilepsy and moderate developmental delay.17 Both patients exhibit low glutamine and high glutamate levels in the brain, which is the probable cause of their disease.18 The S482C and H461L mutations reside in the catalytic domain of GLS, which is identical in the KGA and GAC isoforms.