EXCERPT

> Families living with extremely rare neurodegenerative diseases finally received an answer to the cause of their illnesses, thanks to a researcher's hunch and decades of improvements in DNA sequencing technology.
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> Four different rare diseases are all caused by the same short segment of DNA repeated too many times, a mutation researchers call noncoding expanded tandem repeats. Researchers suspect variations of this type of mutation may cause other diseases that have thus far evaded diagnosis by genetic testing.

Source: https://www.u-tokyo.ac.jp/focus/en/press/z0508_00060.html