Throughout childhood and into early adulthood, Jonathan Karas had a silent menace gathering strength inside his body. By the time he was 28, it stopped being so silent.

Karas woke up before work one day feeling nauseous and with a heaviness in his chest. Soon, he was being rushed to a Boston hospital where incredulous nurses and doctors discovered he was having a heart attack.

Today, 12 years later, he knows it was caused by his untreated history with familial hypercholesterolemia, a genetic condition affecting about one in 500 people that causes up to three times the normal levels of low-density lipoprotein, also called LDL or “bad” cholesterol. It’s an often symptomless condition that can cause heart attacks and strokes in young, fit unsuspecting people who often are exposed to years of elevated cholesterol.

jonathankaras“I had never heard of the term FH,” said Karas, whose high cholesterol first showed up at 13. “My pediatrician at the time thought I was an overweight kid, and I should just watch my diet and exercise. … We monitored it through my early teens, but then I went to college and into my early 20s, and honestly, I didn’t think about it.”

FH is under-recognized and under-treated, said Dr. Samuel Gidding, chief of pediatric cardiology at Nemours Cardiac Center at Alfred.I. duPont Hospital for Children in Delaware. Gidding also is the lead author in the American Heart Association’s first scientific statement about FH, to be released Monday.

“I don’t think people understand the health benefits that can be achieved by early recognition and earlier treatment,” Gidding said. “People see a high cholesterol level and they don’t recognize that it could have been present for a lifetime … And if you see a 40-year-old who just had a heart attack and has FH, if you don’t test that person’s children, then those children will have a heart attack at age 40.”

Blood vessel research has shown that high cholesterol can begin to create atherosclerosis, a buildup of plaque in arteries, as early as 8 to 10 years old. Gidding said children with FH can be started on statins as early as 8. Statins work in the liver to block cholesterol formation.

The American Academy of Pediatrics began recommending in 2011 that doctors conduct a universal cholesterol screening at least once for children between the ages of 9 and 11 and again at 17 to 21. But Gidding said not many doctors are doing that, even though the data show that chronic exposure to cholesterol leads to more severe disease effects.

Karas understands that now all too well. After his heart attack, he had three stent procedures and immediately began taking a statin. He lost more weight, began running and monitoring what he ate more closely.

But even with diet, exercise and the highest dose of medicine, his LDL levels were too high. So, doctors tried adding a few more drugs until they settled on ezetimibe, which helps reduce the amount of cholesterol the body absorbs through the intestine.

Karas said he is stable for now, but these days he has more to think about than himself. His wife, and their 8-year-old son also have FH. His son has a rarer, much more aggressive form of the condition called homozygous FH. Studies indicate HoFH may affect as many as 1 in 160,000 to 1 in 300,000 people.

Every two weeks, he must travel more than an hour each way from their suburban home into Boston to get costly, apheresis treatments that mechanically remove the LDL from his body. Karas’ wife had to leave her full-time job to make sure he could make it to the treatments, leaving each time by 6:30 a.m. and returning home about 12 hours later.

School life hasn’t been easy. His son had surgery to install an access port on his rib cage, limiting his play, and the condition has caused slightly discolored patches on his wrists, elbows and knees.

“He’s had to deal with questions at a very young age about being different,” Karas said. “We are very happy that (apheresis) machine was invented; we know it will prolong his life. But I would prefer he would have another option, so he could feel like a normal kid.”

So, Karas was happy to hear the news this summer that the Food and Drug Administration approved another option for people with FH – two new ultra-lowering LDL drugs called PCSK9 Inhibitors.

Praluent (alirocumab) and Repatha (evolocumab) are both injectable drugs and can reduce LDL levels by as much as 46 percent to 64 percent by targeting the PCSK9 enzyme that regulates how much LDL the liver can flush from the body.

For now, the drugs are approved for adults with FH and others in danger of heart attacks and strokes.

“More options give more people hope,” Karas said.

The nonprofit FH Foundation, which pushed for the drug approvals and has worked to create an FH registry and boost research, estimates FH affects 1.3 million people and that although about a generation has passed since the first statin in 1987, more than 90 percent of people with FH remain undiagnosed.

September is National Cholesterol Education Month in the United States, and the foundation has marked the 24th as FH Awareness Day.

That’s what Gidding hopes the new AHA scientific statement will do – raises awareness and increases action. But along with that, he said FH also needs a new medical classification.

Currently, patients with FH are coded in the ICD-10 system simply as having “garden variety” cholesterol, he said. ICD-10 is the International Classification of Diseases and Related Health Problems, created by the World Health Organization to track health information and used by insurers to determine benefits.

Gidding believes a specific designation for FH will make it easier for track the scope of the problem and for patients to get the key medicine, treatment and attention they need.

“The stories of the people who live with this disease are really important for clinicians to understand,” Gidding said. “How do families live with knowing they can have a heart attack any minute?”