Rare Disease Day 2018 – Familial Chylomicronaemia Syndrome (FCS)

9th March 2018

Many of us wish we ate less fat, but imagine if you had to do this every day?

To mark Rare Disease Day Guts UK, in collaboration with the LPLD Alliance, wants to raise awareness of an inherited condition known as Familial Chylomicronaemia Syndrome (FCS). People with FCS are unable to digest the fat that our gut absorbs from the food we eat due to a mutation on one of five identified genes affecting the action of the enzyme lipoprotein lipase, responsible for metabolising fat.

As there is no treatment currently available, patients have to limit their intake of fat to as little as 10g per day, or risk severe abdominal pain and/or pancreatitis. Recurrent attacks of pancreatitis, if left untreated can develop into chronic pancreatitis.

As the pancreas helps digest fats and other nutrients in our food, a damaged pancreas will impede that digestion, leading to pain, nausea, malabsorption of food, and excess fats in the stools (steatorrhea), all experienced by people with the condition. They are also more at risk of developing diabetes, either as a result of pancreatic damage (insulin insufficiency), from eating higher levels of sugar and carbohydrates – compensating for the lack of fat in their diet (insulin resistance), or for both reasons. Excess blood glucose is turned to fat, so diabetes adds an increased dietary burden.

The liver and spleen can become painfully enlarged and a type of skin lesion known as eruptive xanthmomas can also develop – these are clusters of ‘fat spots’ that appear as reddish-yellow bumps and are sometimes found in the buttocks, knees or arms. These spots appear when people with FCS increase their fat intake and disappear when they eat less fat again. Those affected also complain of less specific symptoms, such as fatigue, memory loss, ‘brain fog’, difficulty breathing and joint pain. Pregnancy can be difficult as blood levels of some fats raise naturally during the third trimester, often to alarming levels, greatly increasing the risk of pancreatitis.

Lipoprotein lipase is responsible for breaking down a type of fat known as triglycerides. Triglycerides are absorbed from the gut into the bloodstream and are distributed to the rest of the body, where they can be burned as a source of energy or stored as body fat. The lipoprotein lipase enzyme is necessary for organs such as the heart, muscles, and adipose tissue (body fat) to use triglycerides, so when the enzyme is absent, the fats remain in the blood, clumping together as chylomicrons. A blood test of people with FCS will show the blood clouded with a milky white colour, caused by the accumulation of chylomicrons in the blood.

There are a number of new treatment options on the horizon, at different stages of development and the LPLD Alliance has information on their website about some of these new medications.

Existing medications that reduce fat levels in the blood, such as statins or fibrates, can also be used though they have little or no effect in people with FCS. This means that those affected need to be extremely careful with their diet, which is severely restricted.

To help us raise awareness of FCS we are inviting supporters and their friends and families to take on the ‘FCS 10g fat Challenge’ on 28th February 2018, for Rare Disease Day.