Disorders of fat digestion can occur for a few different reasons, but they all involve an inability of the body to fully break down dietary fats. This leads to a buildup of fat in the body, which can cause life-threatening side effects if untreated. Disorders of fat digestion are inherited and each one has a different outcome. Some more common examples include Tay-Sachs disease, Gaucher’s disease, and familial hypercholesterolemia.
These disorders can occur because the body does not have enough proteins to break down dietary fats, there are structural errors in certain types of fats, like cholesterol, that make it impossible for the cholesterol to be taken into cells and used for energy, or the cells that should absorb fats have defects in the receptors that take fats in. Most disorders of fat digestion are treatable, although some that arise due to a lack of proteins needed to break certain fats down can be very harmful. A good example of this is Long-chain-3-hydroxy-acyl-CoA-dehydrogenase deficiency (LCHAD).
Symptoms of disorders of fat digestion include:
Which symptoms manifest vary from person to person and between different fat digestion disorders. The severity of the disease and the treatment and management of the disease can affect the severity of the symptoms.
Disorders of fat digestion are caused by gene changes or mutations inherited from the mother, father, or both. Some disorders of fat digestion only need one gene change to show up, as is the case with familial hypercholesterolemia. Others need a gene change from the mother and the father. The pattern of inheritance varies on a case-by-case basis, but every disorder of fat digestion is inherited.
Risk factors include:
To diagnose a disorder of fat digestion, a doctor will look for symptoms specific to a certain disorder. For example, Gaucher’s disease has the unique symptom of a swollen liver and spleen while Tay-Sachs patients have “cherry-red spots” in the back of their eyes. A doctor can perform genetic tests to look for changes in the gene that is responsible for the disease they suspect may be present. Additionally, blood tests can be done to look for the absence of particular proteins that help with fat digestion. These tests together can help your doctor give you a definitive diagnosis.
Complications of these diseases include a shorter life span and death. The symptoms are already fairly severe, and if not managed and treated, they can easily lead to an early death. Certain disorders of fat digestion, like Tay-Sachs, do not have a long-life expectancy in the first place.
Treatment of disorders of fat digestion are wide-ranging. For diseases like Tay-Sachs, that have no cure and a short life expectancy, the goal of treatment is to keep the patient comfortable. For other disorders, enzyme replacement therapy is usually effective. Enzyme replacement therapy gives the body the protein that it’s missing to help it digest the fat properly.
If a fat digestion disorder is caused by a non-functional receptor on a cell that can’t take in fat, medication can be used to treat those disorders and give the body functional receptors. Treatment plans for every disorder of fat digestion involves treating the symptoms, whether they affect the heart, nervous system, liver, or another organ system. People with disorders of fat digestion usually make some changes to diet and exercise regimens as well.