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Inborn errors of metabolism

Familial chylomicronemia syndrome (FCS)

An inherited blood fat disease. The body cannot break down the fats that come from food. Triglycerides rise very high and repeated inflammation of the pancreas can occur.

Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source

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This page is translated from the Turkish original.

This disease is followed through the “Inborn errors of metabolism” group.

Understanding the disease

This section has not yet been reviewed by a physician. It summarises patient information from sources such as MedlinePlus, Orphanet and the NHS in plain language. The disease can differ from person to person; talk to your doctor about diagnosis and treatment.

What happens in this disease?

Fat from food is carried in the blood in packages called chylomicrons. An enzyme called lipoprotein lipase breaks down these packages. In this disease, the enzyme or the proteins that help it do not work. A blood fat called triglyceride rises very high. The blood can look milky.

Which symptoms can occur?

Symptoms may begin in infancy or later.

  • Repeated inflammation of the pancreas (in about 7 in 10 people)
  • Belly pain, nausea and bloating
  • A large liver and spleen
  • Small yellow bumps on the skin (in about half)
  • Poor weight gain in a baby
  • Forgetfulness and difficulty concentrating (sometimes)

How is it diagnosed?

Triglycerides in blood taken while fasting are very high again and again. When the blood is left to stand, a milk-like layer forms on top. A genetic test may show the change, but it does not always find it.

Treatment and care

The main treatment is a very low-fat diet. This diet is planned with a dietitian. Alcohol and sugary processed foods are avoided. Missing vitamins and fatty acids are supplemented. Ordinary blood fat medicines do not work well in this disease. There are approved treatments specific to the disease. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is passed on through recessive inheritance. The mother and father are usually healthy carriers. For a couple who are both carriers, the chance of having an affected child is 1 in 4 in each pregnancy. In marriages between relatives, the chance of carrying the same gene is higher. Genetic counselling is recommended for the family.

Source: NORD: Familial Chylomicronemia Syndrome · MedlinePlus Genetics: Familial lipoprotein lipase deficiency · Orphanet: Familial chylomicronemia syndrome (ORPHA:444490)

Key facts

How common is it?
Prevalence: 1-9 per 1 000 000 (Europe)
How is it inherited?
Autosomal recessive
When does it usually start?
Adolescence, Adulthood, Childhood, Infancy

These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.

You are not alone: patient associations in Türkiye

Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.

We could not find a patient association specific to this disease.

For all rare diseases: Nadir Hastalıklar Federasyonu

Guides related to this disease

  • Special diets and medical nutrition · Metabolic diet, blood monitoring, medical formula and SGK report, sick-day plan, tube feeding and swallowing problems, school meals, supplement warning

Support and help

Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.

News about FCS

Clinical trials (ClinicalTrials.gov)

A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.

This list is not a treatment recommendation. Treatments tested in phase 1–3 trials are investigational (experimental): their efficacy and safety have not yet been proven and they are not approved treatments. Taking part depends on each trial’s criteria and a physician’s assessment; the first step is to talk to the doctor who manages your care.

Questions you can ask your doctor

  • Could this trial be suitable for us?
  • If we take part, how would current treatment and check-ups be affected?
  • Where does the trial take place, and how are travel and accommodation handled?
  • What happens if we want to leave the trial?

ClinicalTrials.gov lists 7 active interventional studies for this disease. 4 are recruiting now; none has a site in Türkiye. Last checked: October 7, 2026.

Selected records (studies with a site in Türkiye first):

See all studies on ClinicalTrials.gov · Joining clinical trials

Inborn errors of metabolism: other news

Medical codes (for talking with your doctor and finding sources)

These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.

Orphanet code: ORPHA:444490

No separate ICD-11 code; WHO classifies this disease under: 5C80.1

Codes checked against WHO ICD-11 and Orphanet on October 7, 2026.

This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.

The information on these pages is for general information only and does not replace medical advice. Talk to your doctor about diagnosis and treatment decisions. In an emergency in Türkiye, call 112.

Every update is based on an open source and labeled with its level of evidence. No advertising and no drug brand names. Our scientific principles

This page was translated from Turkish by the Doktorclub editorial team.