With new results from whole genome sequencing, scientists have identified a cause for a rare genetic disorder known to cause birth defects, bone marrow failure, and leukemia.
Fanconi anemia, a genetic disease that affects 1 in 160,000 individuals worldwide, is characterized by a loss of bone marrow function, and the resulting decrease in blood cell production can produce a variety of conditions like fatigue, anemia, blood clotting failure, and insufficiency of the immune response (NIH
A team of scientists from the Institute for Systems Biology in Seattle, the Free University Medical Center in Amsterdam, and the Luxembourg Centre for Systems Biomedicine, a new study published in Nature Communications
identified a surprising genetic mutation after completing whole genome sequencing of a child affected with Fanconi anemia.
The team located a mutation in the RAD51 gene, one of more than 15 genes with mutations known to cause Fanconi anemia. RAD51, along with other genes with mutations causing the disease, are part of the FA pathway (NIH
). Genes in this pathway are turned on when DNA replication is inhibited because of DNA damage. With mutations occurring in this pathway, DNA repair is not accurately completed and the damage is left unchecked.
What surprised the scientists involved in this study the most was that the RAD51 gene mutation was not found in his parents or his healthy sister. Normally genetic mutations causing Fanconi anemia is recessive and requires inheritance from both parents to cause disease. However, the mutation they found affected only 1 out of 2 gene copies, which they believe suggests a “novel origin” of the mutation.
Additionally, the mutation unexpectedly creates a protein product that hinders the action of the normal half of the protein product so even the non-mutated copy of the RAD51 gene could not effectively repair damage to DNA with other proteins of the FA pathway. Thus, the mutation these scientists identified is dominant.
This discovery is important as medical professionals continue to search for treatment and prevention strategies for this disease. The findings also show how this mutation can cause devastating diseases related to DNA damage like cancer and birth defects.
“Understanding the origins of human cancer will help diagnose it earlier and may help us devise new therapies to prevent or mitigate it,” the team reported in a news release.
Source: Institute for Systems Biology