Doctors often see young people with extremely high levels of fat (triglycerides) in their blood and assume it’s from diet or lifestyle. But this case report shows that a rare genetic condition called adult-onset citrullinemia type II (CTLN2) can hide behind these high numbers. A 30-year-old man had dangerously high triglycerides for 17 years before doctors discovered the real cause through genetic testing. Once diagnosed, a special diet combined with medication brought his triglyceride levels back to normal in just two weeks. This discovery is important because it reminds doctors to look deeper when young patients have unexplained, severe triglyceride problems—it might not be what it seems.
The Quick Take
- What they studied: Whether a rare genetic disorder could be hiding behind what looks like simple high triglycerides (blood fat) in a young adult
- Who participated: One 30-year-old man from Vietnam who had extremely high triglycerides starting at age 13, and experienced a serious pancreas problem at age 28
- Key finding: Genetic testing revealed he had a rare inherited condition (CTLN2) that was causing his high triglycerides. When treated with a special diet and medication, his triglyceride levels dropped from dangerously high (34.61 mmol/L) to normal within two weeks
- What it means for you: If you or someone you know is young and has persistently high triglycerides that don’t improve with normal diet changes, ask your doctor about genetic testing. This rare condition is treatable once identified, but it’s easy to miss
The Research Details
This is a case report, which means doctors are sharing the detailed story of one patient’s experience. A 30-year-old man came to the hospital with a history of extremely high blood fat levels since he was a teenager. Doctors ran many tests to figure out what was causing this problem, but standard explanations didn’t fit. They decided to do genetic testing—basically reading his DNA code—to look for inherited conditions that might explain his symptoms.
The genetic testing found that he had two different mutations (spelling mistakes) in a gene called SLC25A13. This gene controls a protein that helps move important molecules around inside cells. When this protein doesn’t work right, it can cause fat to build up in the blood. Once doctors knew what was really happening, they treated him with a special diet (low carbs, high protein, low fat) and a medication called fenofibrate.
This approach is valuable because it shows how important genetic testing can be when standard explanations don’t work. Instead of just treating the symptom (high triglycerides), doctors found and treated the actual cause.
Case reports like this one are important detective stories in medicine. They help doctors recognize patterns they might otherwise miss. Many young people have high triglycerides, and most of the time it’s from diet or lifestyle. But this case shows that sometimes a rare genetic condition is hiding in plain sight. By sharing this story, doctors alert other physicians to consider genetic testing when standard treatments aren’t working.
This is a single case report, which means it shows what happened to one person, not a large group. While case reports are valuable for spotting new patterns, they can’t prove something works for everyone. The strength of this case is that genetic testing confirmed the diagnosis with certainty. The treatment response was clear and measurable. However, we can’t know from one case whether all people with this condition will respond the same way. This case is best used as a ‘heads up’ for doctors to consider this diagnosis in similar patients.
What the Results Show
The patient’s triglyceride levels were extremely high at 34.61 mmol/L when he arrived at the hospital (normal is below 1.7 mmol/L). After genetic testing confirmed he had CTLN2, doctors started him on a special diet and the medication fenofibrate. The results were dramatic: within just two weeks, his triglyceride levels dropped to normal range and stayed there for the three months doctors followed him.
The genetic testing revealed he carried two different mutations in the SLC25A13 gene. This gene makes a protein that acts like a shuttle, moving important molecules in and out of the cell’s power plants (mitochondria). When this shuttle doesn’t work properly, fat accumulates in the blood.
The treatment plan focused mainly on diet changes—eating fewer carbohydrates, more protein, and less fat. The medication fenofibrate was added to help lower triglycerides further. Importantly, the patient tolerated this treatment well with no side effects reported.
The case also highlights that this patient had suffered a serious complication (acute pancreatitis) at age 28, likely caused by his extremely high triglycerides. This shows how dangerous untreated high triglycerides can be. Once properly diagnosed and treated, he avoided further complications during the follow-up period. The fact that his condition had gone undiagnosed for 17 years (from age 13 to 30) shows how easily this rare genetic condition can be mistaken for common, lifestyle-related high triglycerides.
This case fits with what doctors know about CTLN2—it’s a rare inherited condition that can appear in adulthood with high triglycerides as the main symptom. Most previous cases have been diagnosed in children or through family screening. This case is notable because it shows how the condition can hide for nearly two decades in an adult before being discovered. The rapid response to dietary treatment aligns with what’s known about how CTLN2 works—the condition is very sensitive to carbohydrate intake.
This is just one patient’s story, so we can’t be certain the same treatment will work for everyone with CTLN2. The follow-up period was only three months, so we don’t know about long-term outcomes. We also don’t know if this patient had any other health problems that might have affected his response to treatment. Additionally, this patient is from Vietnam, and genetic conditions can vary between populations, so results might differ in other ethnic groups. Finally, because this is such a rare condition, it’s hard to do large studies to compare different treatments.
The Bottom Line
If you’re a young adult (under 40) with persistently high triglycerides that don’t improve with diet and exercise, ask your doctor about genetic testing for inherited metabolic disorders like CTLN2. This recommendation has moderate confidence because it’s based on one case, but the logic is sound. If genetic testing confirms CTLN2, follow a low-carbohydrate, high-protein, low-fat diet as the main treatment, with medication added if needed. This approach has strong evidence from this case.
Young adults with unexplained, severe, persistent high triglycerides should pay attention to this. Doctors who treat patients with high triglycerides should consider this diagnosis. Family members of someone diagnosed with CTLN2 should also be aware, since it’s an inherited condition. People with a family history of early heart disease or pancreatitis should mention this to their doctors. However, this doesn’t apply to people whose high triglycerides clearly come from diet, obesity, or other known causes.
Based on this case, dietary changes can show results very quickly—within two weeks. However, this is one patient’s experience. Most people should expect to see improvements within 4-8 weeks of starting treatment. Long-term management will require sticking to the diet consistently, as triglycerides may rise again if diet rules are broken.
Want to Apply This Research?
- Track daily carbohydrate intake (grams per day) and weekly triglyceride levels if you have access to blood tests. Set a goal to stay below your doctor’s recommended carb limit and watch for correlation between carb intake and triglyceride levels.
- Use the app to log meals and identify high-carb foods to eliminate or reduce. Create a meal plan featuring high-protein, low-fat options. Set reminders to take fenofibrate if prescribed. Track any symptoms like fatigue or digestive changes.
- Weekly check-ins on diet adherence, monthly triglyceride blood tests (if available through your healthcare provider), and quarterly reviews with your doctor. Use the app to identify patterns—which foods cause triglyceride spikes and which dietary choices keep levels stable.
This case report describes one patient’s experience with a rare genetic condition. It should not be used for self-diagnosis. If you have persistently high triglycerides, consult with your doctor or a lipid specialist before making any changes to your diet or medications. Genetic testing should only be ordered by a qualified healthcare provider. The treatment described in this case may not be appropriate for everyone. Always work with your healthcare team to develop a personalized treatment plan based on your specific situation.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.