A recent study by doctors at Toronto’s Hospital for Sick Children suggests that current screening guidelines for children from HCM families are inadequate and should instead recommend earlier screening exams. In the U.S., screening begins at age 12 pursuant to American College of Cardiology (ACC)/American Heart Association (AHA) guidelines. In Europe, screening begins at age 10 pursuant to the European Society of Cardiology (ESC) guidelines.
A recent study by several HCM genetics researchers around the globe, led by Australia’s Dr. Jodie Ingles, found that 2/3 of genetic mutations previously reported to patients as HCM causative may actually NOT trigger HCM.
A recent paper published in the journal Circulation looked at the clinical course of approximately 4,600 HCM patients over the course of more than 24,000 clinical years, which the paper describes as the largest comprehensive cohort of HCM patients ever studied.
This study examined patients from eight high volume HCM centers which aggregated their institutional data into a database known as the Sarcomere Human Cardiomyopathy Registry (or the acronym the “SHaRe” for short). The results of the study showed that, in general, HCM patients are at substantially elevated risk for atrial fibrillation and heart failure, and have significantly higher mortality rates than that of the general U.S. population.
A recent Canadian study found that children with HCM who carry a single mutation in the MYH7 gene or who have multiple HCM-causative genetic mutations are at increased risk of major adverse cardiac events when compared to children who carry a single mutation in another gene.
Of the 98 gene positive children in this study, those with a MYH7 mutation or those with multiple mutations were more likely to need a myectomy or an ICD or to experience a sudden cardiac arrest or a heart transplant when compared to children with other HCM causative mutations.
The article also suggests that current screening protocols which recommend clinical and genetic screening for HCM beginning at age 12 may be insufficient.
Dr. Heidi Rehm is a human geneticist and clinical laboratory director at Harvard Medical School who has spent much of her career studying the genetics of cardiomyopathy.
Imagine her surprise when she found out that she, her mother and her daughter all have a mutation in the MYH7 gene which has been associated with dilated cardiomyopathy!
The unexpected revelation came as an indirect result of a visit to her daughter’s orthodontist. When one of her daughter’s teeth was delayed coming in, the orthodontist suggested that there might be a genetic cause for the late tooth. This provided the idea behind her high school daughter’s summer biology research project: 2 weeks in her mom’s lab sequencing her exome, looking for a genetic cause for her delayed tooth.
Though the mouth genetics turned out to be normal and the tooth eventually arrived, an totally unexpected incidental finding turned up instead: a variation in the MYH7 gene which has been associated with dilated cardiomyopathy.
A recent study followed 14 patients carrying one of two known genes associated with HCM (MYBPC3 and MYH7) over a 10+ year period . At the time of gene identification, none of the patients shown clinical evidence of hypertrophy. Over the time span of the study, 3 patients, who were then adults, had developed signs of HCM. Hence, the study suggests that periodic screenings are necessary for gene positive individuals throughout adulthood.
According to Cardiomyopathy U.K., the researchers undertook this project due to the lack of information and guidelines available to patients who are gene positive but have no outward signs of the disease.