High triglycerides: can the analysis lie?

Researchers from IIS Aragón speak in this article from 'The Conversation' about cholesterol and triglycerides and the existence of false positives

Let's say you are young, you watch your diet, you play sports and you even take the medication that the doctor has prescribed because in your last blood test your triglyceride levels were through the roof. And yet, analysis after analysis, everything remains the same, with those values ​​skyrocketing.

If you feel identified, do not despair. Your body may be trying to trick your doctor and your genetics may simply be responsible for it.

Our research group at the Miguel Servet Hospital and the University of Zaragoza is dedicated to studying diseases related to cholesterol and triglycerides and finding out the possible genetic causes that may be behind them.

An essential couple, but in the right measure

Cholesterol is a fundamental component of cell membranes, as well as a precursor of numerous hormones, making it essential for life. However, the vast majority of the population limits itself to classifying it into two types, good (HDL) and bad (LDL), and only associates it with its negative side when it accumulates in the arteries and produces cardiac pathologies: heart attacks. , stroke, blood flow problems in the extremities, etc.

Even more unknown is the role of triglycerides, which are usually included in the same bag as cholesterol. But they are nothing more than an energy molecule that allows the accumulation of fatty acids obtained from the diet. Its levels, therefore, are very dependent on the type of diet we follow.

As with cholesterol, high levels of triglycerides are associated with cardiac pathologies, but also with other diseases such as diabetes mellitus, pancreatitis, metabolic syndrome, etc. And although they are more influenced by diet than cholesterol, there are genetic factors that increase their numbers and make them not so easily controllable with medication or a change in lifestyle.

It is important to note that the levels of both lipids cannot be easily regulated with standard drugs. Therefore, when we evaluate a patient for the first time in our unit, we carry out a personal physical examination, a complete analysis and a study of personal and family history. This way we can classify it appropriately and assess its risk of suffering any complications due to the alteration of these values.

False positive

One of these diseases that we have recently studied is known as pseudohypertriglyceridemia. This condition only occurs in young men who, despite having a correct weight and maintaining a good diet and healthy lifestyle habits, have very high triglyceride levels.

The cause is a mutation in a gene known as glycerol kinase. As it is located on the X chromosome, only men suffer from this disease; Women can be carriers of the mutations, but do not suffer from pseudohypertriglyceridemia.

Those affected do not experience any symptoms in their daily lives, but have high blood levels of a molecule called glycerol. That's where the problem lies! The presence of this molecule interferes with the diagnosis of triglycerides, falsifying their values.

This is because a triglyceride is made up of a glycerol molecule linked to three fatty acids (see figure below). In routine analyzes what is detected is that molecule, considering that its number is equal to the number of triglycerides. I mean, the glycerol was fooling us!

For this reason, the analyzes of these individuals show very high triglyceride levels and cause them to be erroneously diagnosed as hypertriglyceridemic. They are even prescribed medication that they do not need and that in the long run can only harm them.

A new evaluation system

In order to identify this type of patient as soon as possible, our research group has created an evaluation system accessible to any primary care doctor. Your score is based on the following characteristics:

1. If it is a young man (under 40 years old) with normal weight who has been given medication to lower those high triglyceride levels, without success.
2. If the patient has normal glucose values ​​and high HDL cholesterol (the so-called good cholesterol) values.
3. If you have normal levels of liver enzymes.

All of these markers are obtained from a routine blood test. To evaluate the possibility of pseudohypertriglyceridemia, we have developed a rating scale from 0 to 14 (table below). Subjects with more than 10 points have a high probability of developing the disease. However, the definitive diagnosis is confirmed by a specific genetic analysis that allows the identification of the mutation in the glycerol kinase gene.

Once the correct diagnosis is made, both the patient and their doctor will know that no medication is necessary. They just need to be aware that those high levels of triglycerides in the tests, which will be repeated throughout the life of the affected person, are not real.

With this research we wanted to provide a practical, clinical and manageable application to primary care doctors to help them in the immense work they do. And at the same time, prevent our body and our genetics from being able to mislead and deceive them at some point.

Authorship:

1. Itziar Lamiquiz Moneo, Assistant professor of Neuroanatomy and researcher at the lipid unit of the Miguel Servet, University of Zaragoza
2. Carmen Rodrigo Carbo, Predoctoral researcher in primary dyslipidemia group, University of Zaragoza
3. Irene Gracia Rubio, Postdoctoral Researcher in the Primary Dyslipidemia group, University of Zaragoza
4. Mª Carmen Garza García, Assistant Professor of the Department of Human Anatomy and Histology. Faculty of Medicine, University of Zaragoza
5. Rocío Mateo Gallego, Assistant Professor with a PhD in the Degree of Nutrition and Dietetics (Department of Nursing and Physiatry), University of Zaragoza
6. Sofia Perez Calahorra, Professor in nursing degree, University of Zaragoza

Source: The Conversation