HNRNPU is a gene on chromosome 1q44 that encodes a protein called heterogenous nuclear ribonucleoprotein U (hnRNPU). The heterogenous nuclear ribonucleoproteins (hnRNP) are a group of proteins with roles in DNA and RNA processing. The hnRNPU protein has several roles, including in alternative splicing, in which RNA is trimmed and re-organized before being translated into a protein. HnRNPU is expressed in various organs within the body, including the brain, and mutations in the gene can cause neurodevelopmental delays and epilepsy.