Women who received their initial risk assessment of being carriers of Duchenne muscular dystrophy (DMD) before 2003 should be reassessed to provide them with the right counseling about the risks of having a child with DMD and developing cardiomyopathy, according to a study published in the scientific journal Neurology Genetics.
Comprehensive molecular testing for DMD-causing mutations has only been available since 2003. According to the authors of the study, “women counseled earlier have outdated risk assessments.”
The study,“Outdated Risk Assessment in a Family with Duchenne Dystrophy: Implications for Duty to Reassess,” reported the case of a family through five generations where genetic testing identified 10 new carriers and 28 women at risk of being carriers of a DMD-causing mutation.
The first individual from the family was a 5-year-old boy who was taken to the doctor with weakness in his muscles and delay in motor development. Medical examination revealed wasting in his calf muscles, reduced muscle strength, and positive Gower maneuver, which is a medical test used to diagnose DMD.
The boy’s grandmother then provided a five-generation history of the family and identified the third cousin of the boy as a patient who was diagnosed with DMD at the center where the research took place. The researchers noted that three other members of the family had died of Duchenne MD at ages 19, 21, and 22.
The boy’s grandmother and her sister had been tested in the 1980s and were told that they were “low carriers” of DMD, while their cousin was told she was a “high carrier,” which made her decide to not any more children.
A review of the medical records of the patient’s third cousin who had DMD confirmed he had a mutation in the dystrophin gene. Genetic testing revealed that the patient also has the same mutation.
When other members of the family were genetically tested, seven new carriers of the DMD-causing mutation were identified, including the patient’s grandmother, who provided the family history for the research.
Based on the pattern of affected males in the family, three additional carriers and 28 women at high risk of being a carrier, including the sister of the grandmother, were identified.
“Given advances in genetic testing technology over the last decade alone, patients with previously negative risk assessments may benefit from periodic reassessment to meet contemporary standards,” the authors wrote.
According to a recent study reviewing 61 articles, most patients would be happy to be reassessed. From the viewpoint of physicians, re-contacting patients is a good idea in principle but practical barriers exist, such as the lack of infrastructure to track former patients and their tests.
“We recommend that healthcare professionals confirm the timing and method of genetic diagnoses, specifically for DMD families reporting negative carrier risk assessments from prior to 2003,” the authors concluded.