Genetic Test Solves Mystery of Family Bleeding Disorder
When a problem with low blood platelet counts surfaced in three generations of the Riggs family, Mayo Clinic doctors went to work to discover what was causing the disorder. Genetic testing revealed the answer, and now, armed with that information, the family is moving forward with confidence.
The 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 Riggs’ 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:
- Offers genetic testing for the early detection of rare blood disorders and bone marrow cancers
- Uses DNA sequencing and conducts research to solve cases with unexplained low blood counts
- Allows for early intervention in which providers can define disease management plans
- Identifies through research how each patient’s genetic makeup affects these disorders and could lead to new individualized therapies
Learn more about the Riggs family’s story in this video:
HELPFUL LINKS
- Learn more about whole-exome sequencing and genetic testing.
- Read about Mayo Clinic’s Department of Hematology.
- Explore Mayo Clinic.
- Request an appointment.