Skip to content
knowrare
HealthSignal
Your condition community

Living with Maternal phenylketonuria

Health differences in babies whose mothers have high blood levels of phenylalanine, an amino acid, during pregnancy.

Understanding Maternal phenylketonuria

Maternal phenylketonuria is a rare condition in which babies are affected by high phenylalanine (Phe) levels in their mother's blood.

The babies do not have phenylketonuria themselves. Their mothers have too much phenylalanine in the blood. The baby may have a small head, slow growth, heart disease, distinct facial features, and intellectual disability. It starts in pregnancy and the newborn period.

Signs & symptoms

Symptoms vary from person to person. GARD lists these among the most common:

  • Small head (microcephaly)
  • Slow growth before birth
  • Heart differences
  • Developmental delay
  • Intellectual disability
  • Distinct facial shape

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include brain and nervous system specialists, ear, nose, and throat specialists and genetic specialists.

  3. Consider genetic testing

    Changes in PAH are linked to this condition. Genetic testing and counseling can help confirm a diagnosis and explain what it means for your family.

  4. Connect with expert centers

    World Craniofacial Foundation may keep lists of experts for this condition.

Care & treatment

Care team
Brain and nervous system specialists (neurologists); Ear, nose, and throat specialists (otolaryngologists); Genetic specialists (geneticists)
Expert care
Expert lists: World Craniofacial Foundation
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with World Craniofacial Foundation and other patient organizations
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
How can phenylalanine levels be managed before and during pregnancy?
Which specialists should follow a pregnancy with PKU?
What care might my child need?

Quick facts

Symptoms usually startduring Pregnancy and as a Newborn
InheritanceAutosomal Recessive
GenesPAH

It occurs in children of mothers with excess phenylalanine in the blood. Changes in the PAH gene, inherited in an autosomal recessive way, are linked to phenylketonuria in the mother.

GeneticNeurologicalInherited Metabolic

Also known as: hyperphenylalaninemic embryopathy; maternal hyperphenylalaninemia; maternal pku; maternal pku (phenylketonuria); pah-gene related maternal phenylketonuria; phenylketonuric embryopathy

Patient organizations

Source: NIH GARD · Maternal phenylketonuriaGARD ID 3413 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Maternal phenylketonuria.

Explore the Maternal phenylketonuria blog

Explore research for Maternal phenylketonuria

Explore actively recruiting Maternal phenylketonuria studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Maternal phenylketonuria with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

Powered by HealthSpark, our AI chat helper

I can help you find recruiting Maternal phenylketonuria studies. Enter a ZIP code, address or city below and I'll look within 50 miles.

Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

Get Signals for Maternal phenylketonuria

Stay in the loop with community stories and updates from medical researchers.

HealthStoryfor Maternal phenylketonuria

Create a living journal that talks back

HealthStory evolves private journaling with a living AI journal that talks back and asks thoughtful questions, helping you capture your Maternal phenylketonuria experiences more deeply and prepare for better conversations with your doctors and care team.

Start your journal

Your journal is private. Sharing your story publicly is a separate choice, made with Share your story above.