Phenylketonuria (PKU) in Grand Rapids, Michigan

Phenylketonuria (PKU) is a rare inherited (genetic) disorder that affects how the body processes protein. It is especially important for families in Grand Rapids and across Michigan to understand PKU because it is routinely screened for in newborns at local hospitals such as Spectrum Health, Trinity Health Grand Rapids, Metro Health, and Mercy Health.

PKU prevents the normal breakdown of an amino acid called phenylalanine, which is found in most protein-containing foods and in some artificial sweeteners.

What Is PKU?

Proteins in our food are made up of building blocks called amino acids. In PKU, the body cannot properly break down one of these amino acids, phenylalanine, because of a missing or severely reduced enzyme called phenylalanine hydroxylase (PAH).

When this enzyme is not working:

  • Phenylalanine builds up in the blood and body tissues
  • High levels of phenylalanine can damage the developing brain
  • Without treatment from early infancy, this can lead to progressive intellectual disability, behavior problems, and seizures

With early diagnosis and proper treatment, children with PKU in Grand Rapids can grow, learn, and develop normally.

How Common Is PKU?

PKU affects about 1 in 10,000 newborns in many populations. In Michigan, including Kent County and the Grand Rapids metro area, all babies are screened for PKU shortly after birth, which helps catch the condition early.

Because PKU is a genetic disorder, it is present from birth and does not develop later in life.

Newborn Screening for PKU in Grand Rapids

How Newborn Screening Works

In Grand Rapids, newborn screening is routinely performed at:

  • Spectrum Health Helen DeVos Children’s Hospital
  • Trinity Health Grand Rapids
  • Metro Health – University of Michigan Health
  • Mercy Health and other local birth centers

Within the first 24–48 hours after birth, a few drops of blood are taken from your baby’s heel and sent to the Michigan Department of Health and Human Services (MDHHS) Newborn Screening Program.

This simple test can detect PKU before symptoms appear, allowing treatment to start as early as possible.

If a screening test suggests PKU:

  • Your baby’s doctor will contact you quickly
  • Additional blood tests will be done to confirm the diagnosis
  • You may be referred to a pediatric metabolic or genetics specialist in West Michigan

Local support and follow-up care may involve coordination with the Kent County Health Department and Grand Rapids–area pediatric specialists.

PKU as a Genetic (Inherited) Disorder

PKU is caused by a change (mutation) in the PAH gene. This gene provides instructions for making the enzyme that breaks down phenylalanine.

How Genes Work

  • Genes are inherited instructions found in almost every cell of the body
  • Each gene comes in two copies: one from the mother and one from the father
  • The PAH gene tells cells how to make the phenylalanine hydroxylase enzyme

When there is a mutation in both copies of the PAH gene:

  • The enzyme is missing or does not work properly
  • Phenylalanine cannot be broken down
  • Phenylalanine builds up to harmful levels in the blood and brain

Carriers and Inheritance Risk

PKU follows an autosomal recessive inheritance pattern.

Each person has two copies of the PAH gene:

  • If a person has one normal copy and one faulty copy, they are called a carrier
  • Carriers of PKU are healthy because the normal gene copy produces enough enzyme to prevent phenylalanine buildup
  • PKU occurs when a child inherits two faulty copies of the gene, one from each parent

When Both Parents Are Carriers

If both parents are carriers of a PAH gene mutation, each pregnancy has:

  • 1 in 4 (25%) chance of a child with two normal genes (not a carrier, not affected)
  • 2 in 4 (50%) chance of a child who is a carrier (one normal and one faulty gene, healthy)
  • 1 in 4 (25%) chance of a child with PKU (two faulty genes, affected)

These risks are the same in every pregnancy, regardless of previous children’s health.

Families in Grand Rapids who learn they are carriers can be referred to clinical genetics services and genetic counselors through major health systems such as Spectrum Health or Trinity Health Grand Rapids for more detailed guidance.

Symptoms of Untreated PKU

Without early diagnosis and treatment, high levels of phenylalanine can interfere with normal brain development. Untreated PKU may lead to:

  • Intellectual disability
  • Developmental delays
  • Behavior and emotional problems
  • Seizures
  • Skin rashes (eczema)
  • A musty or “mousy” odor of the breath, skin, or urine
  • Lighter skin, hair, and eye color than other family members

Because Michigan has cold, long winters and children spend extended periods indoors, untreated PKU can further affect learning and behavior during critical school years. Early treatment helps protect brain development and school performance.

Treatment for PKU in Grand Rapids

Special Infant Formula

If a baby in Grand Rapids is diagnosed with PKU:

  • They will be started on a special low-phenylalanine infant formula
  • This formula provides the protein and nutrients needed for growth, without excess phenylalanine

Lifelong Low-Phenylalanine Diet

As children with PKU grow, they need to follow a low-phenylalanine diet. This typically includes:

  • Allowed / emphasized foods:

    • Special low-protein breads, pastas, and baking mixes
    • Most fruits and many vegetables (in measured amounts)
    • Certain low-protein snacks
    • PKU-specific medical foods and formulas

  • Restricted / limited foods:

    • High-protein foods such as meat, fish, poultry, eggs
    • Dairy products such as milk, cheese, yogurt
    • Nuts, seeds, beans, lentils
    • Regular breads and pastas
    • Foods and drinks containing the artificial sweetener aspartame (often found in diet sodas and sugar-free products)

A registered dietitian specializing in metabolic disorders—often available through major Grand Rapids hospital systems—will help families design a safe, balanced meal plan.

Regular Blood Tests

Regular blood testing is essential to:

  • Monitor phenylalanine levels
  • Adjust the diet and formula as your child grows
  • Ensure levels stay in a safe range to protect the brain

These blood tests can often be coordinated through:

  • Pediatric clinics in Grand Rapids
  • Metabolic clinics at Spectrum Health Helen DeVos Children’s Hospital or other regional centers
  • Support from local public health programs

Maintaining appropriate phenylalanine levels is important throughout life, not just in childhood. Continuing the diet into adolescence and adulthood helps support:

  • School and work performance
  • Concentration
  • Mood and behavior
  • Overall quality of life

Medications and New Therapies

Sapropterin (Kuvan®)

For some individuals with PKU, a medication called sapropterin dihydrochloride (Kuvan®) can be used in addition to diet. Sapropterin is a cofactor that helps boost the activity of any remaining PAH enzyme.

  • Not everyone with PKU responds to sapropterin
  • Response is assessed by monitoring phenylalanine levels after starting the medication
  • If effective, sapropterin may allow a slightly more flexible diet, under medical supervision

This treatment should be managed by a metabolic specialist or pediatric genetics team, which families in Grand Rapids can access through major health systems.

Emerging Therapies

Other novel therapies for PKU are being studied, including:

  • New medications that help reduce phenylalanine levels
  • Enzyme replacement approaches
  • Gene therapy research

Families in Grand Rapids interested in clinical trials or advanced treatments can ask their metabolic specialist about options available in Michigan or the Great Lakes region.

Living With PKU in Grand Rapids, MI

With proper management, children and adults with PKU in Grand Rapids can:

  • Attend school and college
  • Participate in sports and activities
  • Enjoy Michigan’s four seasons, from winter snow days to summer on the lakeshore
  • Lead full, active lives

Practical tips for local families:

  • Plan ahead for school lunches and snacks; work with school nurses and staff
  • Be mindful of holiday meals and winter comfort foods, which are often high in protein
  • When dining out in Grand Rapids, ask about ingredients and choose low-protein side dishes and salads
  • Stay connected with your dietitian and metabolic clinic, especially during growth spurts, illness, or life transitions

Local Resources and Support in Grand Rapids

Where to Get Help

If you live in Grand Rapids or Kent County and have questions about PKU, start with:

  • Your primary care provider or pediatrician
  • Pediatric metabolic or genetics clinics at:
    • Spectrum Health Helen DeVos Children’s Hospital
    • Trinity Health Grand Rapids
    • Metro Health – University of Michigan Health

Additional resources:

  • Kent County Health Department
    Offers public health support, nutrition resources, and information on state programs.
    Website: Search “Kent County Health Department PKU” or “Kent County public health nutrition.”

  • Grand Rapids Public Health and community clinics
    Can help connect families to nutrition counseling, WIC, and insurance or financial assistance programs for medical foods.

  • Michigan Department of Health and Human Services (MDHHS)
    Provides statewide information on newborn screening, PKU guidelines, and support services.

Key Points About PKU

  • PKU is a genetic disorder that prevents the normal breakdown of the amino acid phenylalanine, found in most protein-rich foods.
  • Because phenylalanine cannot be broken down properly, it builds up in the blood and tissues and can damage the developing brain.
  • All newborns in Grand Rapids and across Michigan are screened for PKU in the first few days of life.
  • With early diagnosis and strict treatment, children with PKU can grow and develop normally.
  • PKU is inherited when a child receives two faulty copies of the PAH gene, one from each parent.
  • Carriers of PKU are healthy, because one normal gene copy produces enough enzyme to prevent phenylalanine buildup.
  • Treatment includes a lifelong low-phenylalanine diet, special medical formulas, regular blood tests, and, for some individuals, medications such as sapropterin (Kuvan®).
  • Local healthcare systems in Grand Rapids, MI offer specialized care and support for families managing PKU.

If you are in the Grand Rapids area and have concerns about PKU, contact your child’s doctor or a local pediatric specialist promptly for evaluation and guidance.