Topologically Associated Domains (IMAGE) University of Pennsylvania Caption Researchers at the University of Pennsylvania have found a new common thread linking nearly all of the trinucleotide repeat expansion diseases, which include ALS, Huntington's Disease and Fragile X Syndrome, involving the complicated 3D patterns that the DNA is folded into in order to fit in the nucleus of the cell. Nearly all of the short tandem repeats known to grow unstable in disease are located at the boundaries that separate neighboring folded domains. Credit University of Pennsylvania Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.