For several years, experts believed that Bloom's syndrome was the only condition with a sister-chromatid exchange. However, more recently, researchers have found syndromes that affect the RMI1, RMI2, and TOP3A genes, which interact with the BLM proteins and can cause similar symptoms and an increased risk of cancer.
Experts refer to these as chromosomal instability syndromes. Examples include:
Cockayne syndrome Nijmegen breakage syndrome Russell-Silver syndrome Werner syndrome Rothmund-Thomson syndrome