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DNA Repair Gene’s Role in Acute Myeloid Leukaemia

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Melbourne researchers have uncovered a key factor protecting against age-related DNA damage, providing important clues about how our body guards against cancer.

The discovery was made by identifying a rare genetic mutation in three patients with an unusual, early-onset form of acute myeloid leukaemia (AML). The patients all lacked a DNA repair protein called MBD4, which led to them accumulating DNA damage at a higher rate than normal – as though they were ageing prematurely.

“In this study, we identified AML samples from three patients that showed unusually high rates of methylation damage to the DNA,” said Dr Edward Chew of The Royal Melbourne Hospital. “DNA methylation has a role in fine-tuning gene activity, but it also makes DNA more susceptible to damage.

“When we sequenced the patients’ genomes, we discovered they all carried changes in the same gene, called MBD4. This gene encodes a protein that repairs methylation damage. The loss of MBD4 in these patients explained why their cells had not repaired the damage,” he said.

AML is typically a disease of older adults, with the majority of patients aged more than 70. “The three patients who lacked MBD4 were predisposed to accumulating high rates of methylation damage, which we believe led to them developing AML as young adults (around 30 years old),” Chew said.

Methylation damage...

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