SPATA20 is a 786 amino acid protein that may be involved in fertility regulation. SPATA20 is expressed in testis in an age dependent manner and localizes to round and elongated spermatids. SPATA20 contains a conserved thioredoxin-like domain near the N-terminus region and exists as four isoforms produced by alternative splicing events. SPATA20 is encoded by a gene located on human chromosome 17, which comprises over 2.5% of the human genome and encodes over 1,200 genes. Two key tumor suppressor genes are associated with chromosome 17, namely, p53 and BRCA1. Tumor suppressor p53 is necessary for maintenance of cellular genetic integrity by moderating cell fate through DNA repair versus cell death. Malfunction or loss of p53 expression is associated with malignant cell growth and Li-Fraumeni syndrome. Like p53, BRCA1 is directly involved in DNA repair, though specifically it is recognized as a genetic determinant of early onset breast cancer and predisposition to cancers of the ovary, colon, prostate gland and fallopian tubes.