Huntington’s disease, a genetic condition that causes progressive movement problems, psychiatric issues, and cognitive decline when neurons (nerve cells) in the brain die, is caused by an abnormal expansion of a DNA sequence (called a “CAG repeat”) in the huntingtin gene (HTT). In sufferers of the disease, the CAG repeat is repeated 40 or more times.
A groundbreaking new study, published in Cell, has “changed how we think about how Huntington’s develops,” according to an article in Genetic Engineering and Biotechnology News. The researchers discovered that the mutation in the HTT gene starts off innocuous, but gradually morphs into a toxic form that causes the death of the specific brain cells. In other words, while people inherit the faulty gene from their parents at birth, the disease can get worse over time because the CAG repeat sequence continues expanding in the body’s cells, particularly in the neurons in the brain, as people age. This occurs in “somatic cells”: cells in the body that are not involved in reproduction. Thus, the progression of the disease is driven by changes in the body throughout a person’s life, not solely by the inherited DNA.
This discovery, co-led by Steve McCarroll, PhD, of the Broad Institute, Harvard Medical School, and the Howard Hughes Medical Institute, and Sabina Berretta, MD, of Harvard Medical School and McLean Hospital, could be a game-changer for how Huntington’s disease is studied and treated-– opening up new possibilities for treatments that “could postpone toxicity in many more cells, delaying or even preventing the onset of the disease.“
This is huge news for families with a history of Huntington’s Disease and couldn’t be possible without the diligent, dedicated work of researchers on a selfless mission:
“The point of our work—what we all do—is relieving suffering caused by disease.” – Sabina Berretta, MD
Want to introduce your students to inheritance, biomedicine, and careers in biotechnology and medical research? Check out the Hunt for Huntington’s Disease MiniLab, a hands-on electrophoresis lab kit that can be completed in a classroom period.
