HEATR3 is a 680 amino acid protein existing as three alternatively spliced isoforms and containing two HEAT (Huntingtin, elongation factor 3 (EF3), protein phosphatase 2A (PP2A) and the yeast PI3-kinase Tor1) repeats. HEAT repeats form rod-like helical structures that are involved in intracellular transport. HEATR3 is encoded by a gene located on human chromosome 16, which encodes over 900 genes and comprises nearly 3% of the human genome. The GAN gene is located on chromosome 16 and, with mutation, may lead to giant axonal neuropathy, a nervous system disorder characterized by increasing malfunction with growth. The rare disorder Rubinstein-Taybi syndrome is also associated with chromosome 16, as is Crohn's disease, a gastrointestinal inflammatory condition.