Glycosylphosphatidylinositol Biosynthesis Defect 25, also known as neurodevelopmental disorder with hypotonia and contractures, is related to cerebellar atrophy, developmental delay, and seizures and glucosephosphate isomerase deficiency. An important gene associated with Glycosylphosphatidylinositol Biosynthesis Defect 25 is C18orf32 (Chromosome 18 Open Reading Frame 32). Affiliated tissues include brain and eye, and related phenotypes are hypotonia and coarse hair