Inborn errors of metabolism (IEMs), also known as inherited metabolic disorders (IMDs) are also part of this group of rare diseases. These disorders are caused by genetic defects that affect the body’s ability to break down certain nutrients in food, like protein or carbohydrates and can be detected shortly after birth where new-born screening is available. They often require lifelong management through a severely restricted diet and supplementation with specialized medical nutrition.

Depending on the disorder, often the gold standard management option for people is a lifelong dietary restriction of the nutrient that cannot be broken down by the body. In Tyrosinemia, a disorder of protein metabolism, this means a very restricted low protein diet excluding foods like meat, fish, dairy, grains with foods such as potatoes, rice and pasta allowed only in very small amounts. However, a child still needs some essential components of these foods for growth, development and as a source of energy.