GPATCH4 (G patch domain-containing protein 4) is a 446 amino acid protein containing one G-patch domain. Existing as three alternatively spliced isoforms, the gene encoding GPATCH4 maps to human chromosome 1q23.1 and mouse chromosome 3 F1. Spanning around 260 million base pairs, chromosome 1 is the largest human chromosome and comprises 8% of the human genome. There are about 3,000 genes on chromosome 1, and considering the great number of genes there are also a large number of diseases associated with chromosome 1. Notably, the rare aging disease Hutchinson-Gilford progeria is associated with the LMNA gene which encodes lamin A. Stickler syndrome, Parkinsons, Gaucher disease and Usher syndrome are also associated with chromosome 1. A breakpoint has been identified in 1q which disrupts the DISC1 gene and is linked to schizophrenia. Aberrations in chromosome 1 are found in a variety of cancers including head and neck cancer, malignant melanoma and multiple myeloma.