MYOM3 is a 1,437 amino acid protein that contains five fibronectin type-III domains and four Ig-like C2-type (immunoglobulin-like) domains. Existing as three alternatively spliced isoforms, the gene that encodes myomesin-3 maps to human chromosome 1p36.11 and mouse chromosome 4 D3. Chromosome 1 spans 260 million base pairs, contains over 3,000 genes and comprises nearly 8% of the human genome. Chromosome 1 houses a large number of disease-associated genes, including those that are involved in familial adenomatous polyposis, Stickler syndrome, Parkinson’s disease, Gaucher disease, schizophrenia and Usher syndrome. Aberrations in chromosome 1 are found in a variety of cancers, including head and neck cancer, malignant melanoma and multiple myeloma.