Mallory Riggs' family had a bleeding disorder that spanned three generations and affected the health of multiple family members. But they didn't know the cause of it, the long-term risks associated with it, or the effect it might have on future generations — until a genetic test gave them the information they needed to better understand what was happening.
Finding clues to the mystery of the bleeding disorder began when Mallory's father, Timothy Herrstrom, came to Mayo Clinic for cardiovascular surgery. Previously, Timothy had been diagnosed with Von Willebrand disease after testing revealed he had a low blood platelet count. So before the surgery, Timothy met with Mrinal Patnaik, M.B.B.S., a Mayo Clinic hematologist who specializes in the diagnosis, treatment and prevention of blood diseases.
"I told him we didn't know what exactly he had, but the fact that three generations in his family all have abnormally low blood platelets makes this very likely to be something inheritable."Mrinal Patnaik, M.B.B.S.
When Dr. Patnaik learned Mallory and one of Mallory's young sons also had low platelets, he became suspicious that something else was at work. "I looked at his medical records, and it didn't make sense," says Dr. Patnaik. "I told him we didn't know what exactly he had, but the fact that three generations in his family all have abnormally low blood platelets makes this very likely to be something inheritable."
Dr. Patnaik recommended whole-exome sequencing for Timothy and Mallory. Whole-exome sequencing tests more than 20,000 genes. That represents only about 1% of a patient's DNA, but it's the portion that contains most of the useful genetic information that can pinpoint an illness.
The test showed that Timothy and Mallory had a genetic variation in a gene called RUNX1 causing them to have an abnormally low blood platelet count — a condition called thrombocytopenia. Symptoms include easy or excessive bruising, superficial bleeding into the skin and prolonged bleeding. But that was only part of the problem.
"This gene mutation not only causes low blood platelets, but increases the risk for certain blood cancers to develop overtime like myelodysplastic syndrome and acute myelogenous leukemia," Dr. Patnaik says.
"Now that we have answers, I can let Sawyer be himself, and be that active little boy and do all of the things that he loves and enjoys doing."Mallory Riggs
Although there’s no specific remedy for the condition, having the genetic information gave the family some peace of mind. And it put Mallory more at ease in caring for her son Sawyer, who also was diagnosed thrombocytopenia when he was 10 months old. Today, Sawyer is 5 and the busiest and most active of Mallory's three boys.
"Now that we have answers, I can let Sawyer be himself, and be that active little boy and do all of the things that he loves and enjoys doing," says Mallory. "We can let our kids be kids, wrestling, playing and climbing and not being so concerned about all of the what ifs."
Genetic testing was key to unlocking the answers for the Riggs family, according to Dr. Patnaik. "Having a correct diagnosis impacts the family's medical care today and in the future," he says. "We now understand how to treat them for surgeries. The family has a screening tool, and we are monitoring them annually."
Patients like those in the Riggs family, who have rare, undiagnosed medical conditions, can spend years meeting with multiple health care providers to seek a diagnosis. They often try a myriad of treatment plans that aren't appropriate and many never find the underlying cause of their disorders.
Helping this family inspired Dr. Patnaik to start a first-of-its-kind Premyeloid and Bone Marrow Failure Disorder Clinic at Mayo Clinic, so other patients can benefit from precision diagnosis and new individualized therapies. This new clinic:
Learn more about the Riggs family's story in this video: