C18orf32 is a protein essential for glycosylphosphatidylinositol (GPI) biosynthesis, specifically functioning in GPI-inositol deacylation 1. The protein localizes to the endoplasmic reticulum and is critical for proper GPI-anchor synthesis and cell surface protein anchoring 1. Loss-of-function mutations impair PIPLC sensitivity of GPI-anchored proteins, disrupting normal GPI biosynthetic pathways 1. C18orf32 is involved in multiple disease contexts. Homozygous loss-of-function variants cause an autosomal recessive neurodevelopmental disorder characterized by global developmental delay, brain anomalies, hypotonia, and contractures 1. Additionally, the chimeric RNA RPL17-C18orf32 participates in environmental toxicity responses; the CYP1A1/RPL17-C18orf32 axis mediates polycyclic aromatic hydrocarbon-induced respiratory toxicity, DNA damage, and cellular dysfunction 2. C18orf32 expression is dysregulated in Alzheimer's disease pathology. In cognitively healthy individuals accumulating brain amyloid, RPL17-C18orf32 showed strong evidence for pathogenic relevance with high direct association scores for Alzheimer's disease risk 3. These findings establish C18orf32 as a multifunctional gene involved in GPI biosynthesis, neurodevelopment, environmental toxin response, and Alzheimer's disease pathogenesis.