Researchers at the University of Pennsylvania have studied the genetics of a class of neurological disorders that includes Huntington’s disease and Fragile X Syndrome. They found that there were similarities in the 3D shape of the folded DNA. To learn more about this, you can view the source press release at the University of Pennsylvania’s website by clicking here. Alternatively, you can view the original study by clicking here.
DNA is present in almost every cell in the body, and contains ‘instructions’ for building components of the body. Most DNA is inside the nucleus of the cell, although some is in mitochondria. DNA is made up of base pairs that bond together to form a double helix shape. According to Penn’s article, this double helix DNA needs to further fold into a complicated 3D pattern in order to fit into the nucleus of the cell. The ability to map the 3D folded shape of DNA is a relatively recent development.
It is very common for sections of DNA to contain repeating base pair sequences (known as short tandem repeats). However, some people can have extremely long and unstable repeating sections called trinucleotide units, which is known as a trinucleotide repeats (TNR) expansion disorder. TNR expansion disorders have been linked to several severe neurodegenerative and neuromuscular disorders, such as Huntington’s disease and Fragile X syndrome.
Researchers found that a strong correlation between unstable short tandem repeats, a misfolding of the genome’s 3D shape, and pathologic gene disruption. The unstable repeating sections linked to disorders were shown to often be near ‘boundaries’ in the DNA. One of the questions the researchers asked about these results was whether the correlation was causal, and, if so, in which direction. The boundaries could in some way cause the repeats, or the repeats could cause a boundary to form there. Scientists are now attempting to answer that question in an on-going study.