Japanese and American scientists have made a fantastic discovery. An incurable type of chromosomal abnormality, in which one end of the chromosome has fused with the other, is known as a “ring chromosome.” The presence of ring chromosomes often correlates with neurological abnormalities. The collaborative work by these two researcher groups has shown that if induced pluripotent stem cells are derived from abnormal adult cells that contain ring chromosomes will spontaneously repair themselves.
This research team, which included researchers from Kyoto University professor and iPS cell pioneer Shinya Yamanaka, also included Yohei Hayashi and other researchers from the U.S.-based Gladstone Institutes.
“I was very surprised at the results,” said Hayashi. “There still remains a risk, but the findings may lead to the development of breakthrough treatment for chromosomal abnormalities.”
Normal chromosomes pairs consist of two rod-shaped chromosomes, but in the case of a ring chromosome, the arms of one of the two chromosomes are fused to form a ring.
Ring chromosomes tend to be associated with mental disabilities and growth retardation, and there are no therapeutic strategies for ring chromosomes.
Hayashi and his colleagues developed iPS cells from skin cells of patients with ring chromosome disorder to study the effects of this chromosomal defect in stem cells. However, the ring chromosomes could not be observed in the engineered iPS cells made from this patient’s cells.
For reasons still unknown, only normal chromosomes survived, according to the researchers. Typically, a cell that contains ring chromosomes divides into two abnormal cells in the normal mitotic process.
These findings were published in the online edition of the British science journal Nature on Jan. 13, 2014.