t(X;18)(p11.23;q11)

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A cytogenetic abnormality that refers to a chromosomal translocation that involves the short arm (p11.23) of the X chromosome and the long arm (q11) of chromosome 18. It is associated with the expression of SS18/SSX1 fusions and the development of synovial sarcoma.