PPT1 and Pelizeaus-Merzbacher spectrum disorder: The following biochemical and genetic tests were normal: array CGH, fragile X test, TORCH titers, quantitative plasma amino acids, quantitative urine organic acids, fluorescentin-situ hybridization (FISH) test for Pelizaeus-Merzbacher disease, very long chain fatty acids, enzyme assays for CLN1 (PPT1 – palmitoyl-protein thioesterase 1) and CLN2 (TPP1-tripeptidyl-peptidase 1), and 7-dehydrocholesterol.