Inborn Errors of Metabolism

What does “inborn” in IEM mean?

genetic/inherited

What is an inborn error of metabolism (IEM)?

A genetic disorder causing a missing or defective enzyme

What do enzymes do?

Speed up chemical reactions

What does metabolism involve in IEM?

Energy production and cell function

What are the two major problems in IEM’s?

Toxic build up & Lack of product

Why does toxic buildup happen?

Substances cannot be broken down

Why does lack of product happen in IEM?

Needed product cannot be made

What happens when cells do not get enough glucose

Body breaks down other compounds for energy

What is the problem in galactosemia?

Cannot properly break down galactose

What accumulates in galactosemia

Galactose

What diet is used for galactosemia

Galactose/lactose-free diet

What is the problem in glycogen storage disease (GSD)?

Cannot properly break down glycogen

Main result of GSD?

Hypoglycemia

MNT for glycogen storage disease?

Consistent supply of glucose/carbohydrates

What accumulates in urea cycle disorders?

Ammonia

Why is ammonia dangerous?

Toxic to the brain

MNT for urea cycle disorders

Protein restriction

What accumulates in PKU?

Phenylalanine

What is deficient in PKU

Tyrosine

What can high phenylalanine affect?

the brain

MNT for PKU

Low-Phenylalanine diet

Why is tyrosine supplement in PKU

it cannot be made adequately

What accumulates in MSUD

Branched -chain amino acids (BCAAs)

Why is it called maple syrup urine disease

Urine smells like maple syrup

MNT for MSUD

Restrict BCAAs (protein)

How are calories provided in MSUD?

Carbs and fat for energy

What is the main pattern for all IEMs?

Enzyme problem—> toxic build up and missing product