Metabolic Disorders

Overview

Metabolic disorders are lifelong diseases, but early treatment can often alter their natural progression. You inherit most metabolic disorders.

Diagnosis

Physicians at IU Health diagnose some metabolic conditions within a few days of a child’s birth through newborn screening tests. They work with metabolic faculty and nutrition specialists to quickly identify newborns with these conditions.

Tests use a blood sample from the newborn’s heel to check for treatable disorders that could otherwise go undetected. If your infant has an abnormal metabolic screening result, a physician should evaluate your child within five to seven days. Most treatable metabolic conditions require special diets to ensure proper health and prevent complications.

IU Health physicians’ affiliation with the Riley Hospital for Children at Indiana University Health Biochemical Genetics Program gives them access to the only lab in the state equipped with advanced technology used to identify metabolic conditions.

Types of Metabolic Disorders

Many different types of metabolic disorders exist—some affect protein metabolism and others affect carbohydrates or fats, or combinations of these molecules. Other more rare metabolic disorders exist. A few examples of the more common types include:

• Phenylketonuria (PKU)
• Galactosemia
• Tay Sachs
• Wilson’s disease

The most common metabolic condition is phenylketonuria (PKU). Newborns receive screenings for PKU as well as galactosemia.

Phenylketonuria (PKU)

A deficiency in an enzyme called phenylalanine hydroxylase causes PKU. This enzyme helps your body break down and use the phenylalanine found in protein to make tyrosine, which in turn makes neurotransmitters. Phenylalanine, an essential amino acid, builds other proteins. When your body cannot utilize phenylalanine in the normal way, this amino acid will accumulate in your blood and brain, and cause serious damage

PKU Symptoms

Left untreated, PKU will lead to:

• Developmental delays
• Intellectual disabilities
• Seizures
• Behavioral problems
• Growth impairment

PKU Treatment

To protect the body’s systems, you must follow a special restricted-protein diet. Instead of natural protein, you take a prescription formula for incomplete protein supplementation with all the necessary amino acids except phenylalanine. With PKU you must have at least some phenylalanine for your body to function properly so your physician will check your blood for phenylalanine levels.

At the PKU treatment center, the only one of its kind in the state, physicians, dietitians, social workers and counselors work closely with you and your family to assist you in managing this complicated and costly disease. Your care team utilizes grant programs to ensure you have access to the food and formula you or your child needs to thrive. They help you adjust the levels of phenylalanine in you or your child’s diet to maximize health and growth through maturity. If appropriate, your physicians prescribe medicines specifically designed to boost PKU enzyme function.

Galactosemia

Galactosemia occurs when you have a shortage of one of three enzymes needed to break down galactose, a component of lactose, a sugar found in milk. When milk consumption begins, babies become ill with vomiting, jaundice, lethargy and sepsis—which can be fatal. Liver and renal failure can also occur.

Symptoms of Galactosemia

If left untreated, or partially treated, galactosemia may have serious complications, including:

• Failure to thrive
• Jaundice
• Cataracts
• Hypoglycemia
• Sepsis

Galactosemia Treatment

Babies, children and adults with galactosemia must avoid milk and all dairy products from milk in their diets. Dietary restrictions should begin as soon as possible. Galactosemia occurs in one in every 30,000 to 60,000 births.

Treatment

IU Health physicians will work with you and your primary care physicians to design an appropriate treatment plan. They will educate you and your family about the disease and its genetic basis, and treatment. They provide long-term care and support in managing metabolic diseases.

IU Health’s partnership with Indiana University School of Medicine and specialists in clinical and biochemical genetics allows you to receive services from genetics clinics. This collaborative relationship gives you access to the latest research and treatments for inborn errors of metabolism.

If you live with a metabolic disorder, you can lead a normal, healthy life if you stay on track and tightly control your nutritional intake. Treatment options include:

• Genetic counseling. When physicians diagnose your newborn baby with a metabolic disorder, IU Health genetic counselors help you understand the condition, its lifelong implications and how it will affect your child as he or she matures.
  
• Nutrition. Specialized or restrictive diets play a key role in treating metabolic disorders. IU Health dietitians have years of experience managing PKU, galactosemia and other metabolic conditions. The nutrition experts meet with you regularly and teach you how to take a proper blood dot for routine metabolic and blood tests. Every time your dietitian receives your test results, he/she reviews them with you. He/she adjusts your diet, supplements and formula to accommodate your child’s growth.
• Special diets. Some metabolic conditions require expensive foods. People with PKU must eat low-protein diets. The specific diet depends on how much enzyme function resides within each person. You take a special formula supplement three to four times a day. As you or your child grows, it becomes more difficult to eat enough and feel full. Our PKU treatment center works with you to access special foods.
• Medicine. A medicine for PKU helps your body make the most use of remaining enzyme function that breaks down the phenylalanine in protein. While not an enzyme replacement, it changes the shape of an enzyme to make it work properly. For PKU patients with certain remaining levels of enzyme function, this medicine removes the need for formula, improves mental focus and helps with an overall feeling of well-being.
• Research. Physicians and researchers at IU Health investigate the causes of and treatments for metabolic disorders. As the only center in Indiana conducting active research on PKU, IU Health has two clinical research trials now underway studying the effects of medicines used to treat PKU. One study monitors the neurocognitive (reduction in cognitive function) improvements of medical PKU management. Another one tests a substitute enzyme replacement therapy for PKU.