The same study also found that gene positive children without overt signs of the disease are at relatively low risk for cardiac events.
The study included 119 children, positive for at least one HCM gene, with a median age of 12.1 years. 8 of these children (6.7%) received a HCM diagnosis within the time span of the study [which varied from 3.1 to 10.7 years]. 1 of the 8 diagnosed children suffered a cardiac event which necessitated implantation of an implantable cardioverter defibrillator or ICD.
The study did caution, however, that because severe hypertrophy and cardiac events may develop, it is important to refine risk stratification and long term follow up procedures for gene positive kids.