GPATCH8 is a nuclear RNA-binding protein containing G-patch and zinc finger domains that functions as a splicing regulator with broad implications for cancer and neuropsychiatric disease. Primary function: GPATCH8 modulates pre-mRNA splicing through interaction with the RNA helicase DHX15 and participates in branchpoint selection quality control 1. Mechanism: GPATCH8 cooperates with mutant SF3B1 (a common cancer-driving splicing factor mutation) to promote aberrant splicing patterns 2. The protein localizes to nuclear speckles and contains ultraconserved, alternatively spliced exons regulated by RBFOX proteins 3. Disease relevance: GPATCH8 is required for SF3B1-mutant-induced splicing defects in hematologic malignancies; GPATCH8 silencing corrected one-third of mutant SF3B1-dependent splicing abnormalities and improved hematopoiesis in SF3B1-mutant models 1. GPATCH8 also interacts with schizophrenia-associated proteins and influences neurodevelopmental gene splicing 3. Clinical significance: GPATCH8 represents a therapeutic target for SF3B1-mutant cancers 2. Additionally, GPATCH8 variants are associated with hyperuricemia in osteogenesis imperfecta patients 4 and glycated hemoglobin levels 5, suggesting metabolic and systemic disease involvement.