t(7;9)(q34;q34.3)

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A chromosomal translocation involving breakpoints within the q34 band on the long arm of chromosome 7 and the q34.3 band on the long arm of chromosome 9.This rearrangement is associated with aberrant expression of the NOTCH1 gene and T acute lymphoblastic leukemia.