Inherited Metabolic Disorders

Inherited metabolic disorders are medical problems that happen when specific instructions (genes) in your body don't work correctly. These instructions control how your body processes food and other substances. Different problems with these instructions lead to different types of disorders. Usually, both parents pass on the faulty instruction. Sometimes, though, only one parent passes it on, most often the mother. These are also called inborn errors of metabolism.

Metabolism is like your body's internal chemical factory. It's a series of complex processes that keep you alive and functioning. These processes include:

• Building and getting rid of things: Your body needs to make certain substances. It also needs to break down substances it no longer needs.

If these processes don't work correctly, a metabolic disorder can result. This can be because an important chemical worker (enzyme) in the process is missing or not working properly, or there might be another problem in the system. Inherited metabolic disorders are grouped based on what substance in the body is affected. This grouping depends on whether a substance builds up too much because it can't be broken down, or if it's not present enough because it's missing or not working as it should.

Many inherited conditions affect how the body processes food. These conditions, called inherited metabolic disorders, happen because of problems with specific genes. Each disorder is different, and symptoms vary greatly depending on which gene is affected and how much it's affected.

Some examples of these inherited metabolic disorders include:

• Hunter syndrome: This disorder affects the body's ability to break down certain substances. Symptoms can include problems with growth, development, and the body's immune system.

• Krabbe disease: This disorder impacts the body's ability to make certain fats, crucial for healthy nerve function. Early symptoms can include developmental delays and problems with movement and coordination.

• Maple syrup urine disease: This is a condition where the body struggles to process certain amino acids (building blocks of proteins). The name comes from the distinctive sweet smell of urine in affected individuals. Symptoms can range from mild to severe, often appearing shortly after birth, and can include feeding difficulties, lethargy, and neurological issues.

• Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS): In MELAS, the mitochondria, which are the powerhouses of cells, don't work properly. This leads to a range of symptoms, including muscle weakness, seizures, developmental delays, and stroke-like events.

These are just a few examples. There are many more inherited metabolic disorders, each with its unique set of symptoms and challenges.

If you're worried about how your child is growing or developing, or if you have health concerns yourself, please see a doctor or other medical professional. It's important to discuss any questions or worries you have with a healthcare provider.

Some inherited conditions affect how your body processes food and other substances. These conditions happen when there are problems in specific instructions (genes) that tell your body how to do this processing, or metabolize things. Different problems in different genes lead to different inherited metabolic disorders. Usually, these gene problems are passed down from both parents. However, sometimes the problem comes from only one parent, often the mother. There are many different types of these inherited metabolic disorders, each linked to a specific gene change.

Having a family history of inherited metabolic disorders can increase the chance of a child inheriting the condition. This means if either parent carries a gene change linked to these disorders, their child might be at higher risk. Some couples choose to get genetic testing before trying to get pregnant. This testing looks for specific gene changes that could potentially cause certain inherited metabolic disorders in their future children. Essentially, it helps them understand the risks involved and make informed decisions about their family planning.

Some inherited conditions that affect how the body processes food (metabolic disorders) can be detected in different ways. Some are found before a baby is born, others during newborn screenings, and still others only after a child or adult develops symptoms.

If you or your child might have a metabolic disorder, doctors might use several methods:

• Physical Exam and Medical History: The doctor will examine you or your child physically and ask about any symptoms you're experiencing, past illnesses, and your family's medical history. This helps them pinpoint possible problems.

• Blood and Urine Tests: These tests look at how well your body is breaking down and using food. Other tests might also be needed, depending on the situation.

• Genetic Testing: This testing looks at your genes to identify the specific metabolic disorder. If one family member has a metabolic disorder, doctors often recommend genetic testing for other relatives to see if they carry the same gene changes. This can help them understand their risk.

• Preconception Screening (Carrier Testing): For couples planning a pregnancy, a test called carrier testing can check for gene changes that might increase the risk of a child inheriting a metabolic disorder. This can be done before getting pregnant.

• Genetic Counseling: A genetic counselor can discuss the results of any genetic tests and explain the risks of passing on a metabolic disorder to future children. They can also talk about newborn screening options.

• Specialist Consultations: Some metabolic disorders can increase the risk of other health problems, like heart, vision, or hearing issues. Your doctor might recommend seeing specialists in these areas.

Genetic testing is important for identifying the specific metabolic disorder. If one family member has a metabolic disorder, genetic testing and counseling are often recommended for other family members. This helps everyone understand their risk and plan for the future. Preconception screening (carrier testing) allows future parents to learn about their risk of passing on a metabolic disorder to their children before they get pregnant.