Inherited Metabolic Disorders – Symptoms and Causes
Overview
Inherited metabolic disorders are a group of genetic conditions that affect how the body processes certain substances.
These disorders interfere with the body’s ability to carry out essential chemical reactions, known as metabolism, which help produce energy, build important compounds, and eliminate waste.
Because these conditions are present from birth and result from changes in genes, they are often called “inborn errors of metabolism.” Scientists classify these disorders based on the type of substance involved and how the metabolic process is disrupted.
Signs and Symptoms
People with inherited metabolic disorders may show different symptoms depending on which disorder they have. Common symptoms include:
- Feeding problems or poor appetite
- Growth issues like being shorter than expected
- Unusual body odor
- Extreme tiredness
- Muscle weakness
- Seizures
- Delayed development in babies and children
- Breathing problems
Many symptoms appear in early childhood, but some disorders may not cause noticeable problems until later in life.
When Medical Care Is Needed
See a doctor right away if your child shows:
- Sudden changes in behavior or movement
- Confusion or loss of consciousness
- Repeated vomiting
- Unusual breathing patterns
- Seizures
Regular check-ups are important for children with known metabolic disorders. If you notice new symptoms or if existing symptoms get worse, contact your healthcare provider.
Causes
Inherited metabolic disorders happen when genes that control metabolism have changes or mutations. These disorders come in hundreds of different types, each linked to specific gene changes.
Most often, these gene changes pass from both parents to a child. In some cases, only one parent—usually the mother—passes on the changed gene.
Metabolism involves several key chemical reactions that keep the body functioning properly. These include:
- Energy Production: Enzymes help break down food or chemicals for immediate energy use or storage.
- Substance Management: Creating necessary substances and removing unneeded ones.
Metabolic disorders develop when these processes malfunction. This usually happens because:
- An enzyme is missing or present in insufficient amounts
- Other problems disrupt normal metabolic pathways
Scientists classify these disorders into different groups based on:
- The specific substance affected
- Whether the problem involves excessive buildup of substances that can’t be broken down
- Deficiency or absence of necessary substances
Risk Factors
Parents who carry certain gene changes may pass them to their children, increasing the chance of inherited metabolic disorders.
When one parent has this gene change, the risk goes up. If both parents have it, the risk is even higher.
Some couples choose to get carrier testing before trying to have a baby. These tests can find gene changes that might affect future children.
Testing helps parents understand potential risks and make informed decisions about family planning.
