Our daughter has moderate pulmonary stenosis. She is nearly 3. Our son is 4 (both Noonan’s LZTR1). No detected cardiac issues. Is there any indication of the age any other cardiac issues—if they occur—might become apparent?

We are still learning about how the heart is affected in LZTR1, but it is very unlikely that any valve changes will develop if they are not present now. What can develop over time, and needs regular follow up, is hypertrophic cardiomyopathy. In most cases, we think this is often present very early on, but it can sometimes develop later in life, so we would recommend ongoing cardiac screening.