Primary immune deficiency (PID) disorders are a group of conditions that make it more difficult for patients to fight off disease. Children with primary immune deficiency may become seriously ill from common infections that would be harmless in other kids. Sometimes, doctors are able to pinpoint the cause of a child’s PID, but for other patients the cause remains unknown.
Researchers at CFRI, BC Children’s and UBC recently published a study in the Journal of Allergy and Clinical Immunology (May 2014) that identifies a new form of PID caused by a mutation in a gene called MALT1. CFRI Postdoctoral fellows and study co-authors Dr. Jacob Rozmus and Dr. Shan-Yu Fung explain that even though this mutation has only been identified in 3 families so far, the research has wide ranging implications for children and their families.
What did you discover as a result of your research?
Dr. Fung: We sequenced a portion of the genome of a 15 year old girl who has suffered from a number of serious health problems since birth including rashes, gastrointestinal disease, multiple lung and skin infections, and low bone density. Although doctors were able to treat the individual symptoms they didn’t understand the underlying cause of the girl’s poor health.
By comparing this patient’s genetic sequence to other human genomes and those of her parents and healthy brothers, we found she has a genetic mutation that causes her to have very low levels of a protein called MALT1 that plays a key role in the immune system.
Previous research has shown that disruptions in the MALT1 gene can cause immune problems in mice, and we now have evidence that MALT1 may play a similar role in human immune disorders.
How could your discovery lead to new treatments for patients with primary immune deficiency diseases?
Dr. Rozmus: Now that we understand the underlying cause of this particular patient's immune deficiency, we’re looking into the possibility of treating her with new therapies which would effectively replace her immune system.
It’s very likely there are other children with unexplained illnesses who suffer from the same mutation as this patient or from a similar mutation, and doctors may now be able to provide them with a clear diagnosis and offer treatment options. Our research has also contributed to a better understanding of what the MALT1 protein does and how its disruption affects the immune system. This may one day lead to new, targeted treatments that work by improving the function of the MALT1 protein.
How will this research help children in British Columbia?
Dr. Rozmus: Children with PID often suffer from serious health problems for years without explanation. These children have better outcomes if they receive treatment for their underlying immune deficiency early in life, before they suffer permanent damage to multiple organs.
In addition to helping clinicians diagnose other children who suffer from the same mutation as the patient in the study, this research may also eventually contribute to treatments for other diseases. For example, researchers already know that overexpression of the MALT1 protein contributes to certain types of cancer, and our work may aid in the development of new cancer treatments that work by inhibiting the expression of MALT1.
How did CFRI’s proximity to BC Children’s aid in this research?
Dr. Fung: Medical research often suffers because researchers work in cloistered academic settings and don’t have access to the patients they are trying to help.
At CFRI, researchers are able to study patients who are receiving treatment at BC Children’s including the patient who was profiled in this study. These patients in turn benefit from having access to a research facility that can offer state of the art services like genomic sequencing.
Because of work done at CFRI, the patient in this study finally has a clear diagnosis after a lifetime of poor health.
What are your next steps?
Dr. Fung: We’re going to continue investigating the role MALT1 plays in the immune system and the role it plays in other cellular systems in the human body. It’s possible there are other diseases that are caused by MALT1 disruptions. On the clinical side, we’re going to look for the mutation in other children with similar symptoms and investigate possible treatment options.
CFRI Director of Clinical Research Dr. Stuart Turvey led the research team for this study. Dr. Margret McKinnon, Dr. Rusung Tan, Dr. Anne Junker, Dr. Michael Seear, Dr. Kirk Schultz, Dr. Millan Patel and Dr. Jan Friedman also contributed research.