Tracy is a 40-year-old African American who is an aerobics instructor, a mother of two and a college student pursuing a degree in business. She looks like any other normal person, except that she is not normal. Not normal in the sense of her LDL cholesterol levels. Her LDL cholesterol is 14, where as the normal range for the population is somewhere around 100.
Scientist have been studying the anomaly in cholesterol levels in people like her and investigating what makes them have such low levels. And whether, there is a negative health effect of having such low LDL levels. They found their answer. Tracy and people like her are carriers of a mutation in a gene called PCSK9. People who carry this mutation have very low cholesterol levels and have a 90% reduced risk of heart disease.
Tracy has a genetic gift. But there are millions of people who suffer from high cholesterol and have to endure the side effects of cholesterol lowering drugs called statins.
It’s estimated that up to 20% of patients cannot tolerate statins' side effects, which include muscle pain and even forgetfulness. And in many others, the drugs simply don't control cholesterol levels well enough.
Now Tracy’s gift has been put to good use, leading to the development of a new class of cholesterol lowering drugs, called, well, PCSK9 drugs. Unlike statins, this drug works naturally and is not likely to produce side effects. These drugs worked so well that FDA had to halt the clinical trial early.
So how does the PCSK9 drug work?
The human body has many sensors that allows it to sense and control the levels of various biochemicals, hormones, enzymes and proteins. If the sensors are not working properly, things can go haywire. For example, the smoke sensor in your room is supposed to sense smoke to trigger the sprinkler in the event of fire. However, if there is dust accumulated on the surface of the sensor, then the smoke is not detected and sprinkler not triggered.
Another example is that of a temperature sensor which shuts off the air conditioner once the set temperature is reached. If the sensor is not functional, the AC will continue to operate without shutting off and cool the room to much lower temperature than desirable. Similarly, the liver has a cholesterol sensor. If the cholesterol sensor does not detect enough cholesterol, because there is biological “dust” accumulated on the sensors, then the liver thinks there is not enough cholesterol in the system, and starts producing more and more of it. This dust is PCSK9. For people like Tracy, their body does not produce PCSK9, hence no “dust” to block the sensor.
Though Tracy is an extreme case, a lot of us have various mutations in the PCSK9 genes and other genes such as APOA, LDL, LPL, APOB and other genes that modulate our cholesterol levels and predisposition to heart disease. Being informed about the various mutations we carry can help develop a personalized diet, exercise and preventive program that is uniquely tailored for us.