Thrombospondin Type-1 Domain-Containing Protein 1 (THSD1) is a single-pass type I membrane protein. THSD1 contains a signal peptide and one TSP type-1 domain that is found in thrombospondin. THSD1 is a good novel candidate for TSG as it has been mapped to 13q14. Alternatively spliced transcript variants encoding distinct isoforms have been observed. THSD1 may be involved in the complement pathway.