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Living with PHGDH deficiency

A rare inherited brain condition with a small head, seizures, and delayed development, usually starting in infancy.

Understanding PHGDH deficiency

PHGDH deficiency (phosphoglycerate dehydrogenase deficiency) is a rare inherited condition with a small head, delayed development, and seizures.

Most people have the infantile form, which is the most severe. Brain cells and the fatty covering of nerves (myelin) are affected, so the head grows slower than the body. Many babies have trouble feeding. Juvenile and adult forms are very rare and appear later. GARD lists onset as a variety of ages.

Signs & symptoms

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

  • Small head (microcephaly)
  • Severe delays in development
  • Seizures, including infantile spasms
  • Feeding difficulties
  • Poor weight gain
  • Muscle stiffness (spasticity)

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 and genetic specialists.

  3. Consider genetic testing

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

Care & treatment

Care team
Brain and nervous system specialists (neurologists); Genetic specialists (geneticists)
Expert care
Ask about multidisciplinary care centers for rare conditions
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 rare disease patient organizations for support
  • 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
What seizure treatments are recommended, and how early should they start?
Would PHGDH testing help our family?
How can we support feeding and development?

Quick facts

Symptoms usually starta variety of ages
InheritanceAutosomal Recessive
GenesPHGDH

Changes in the PHGDH gene cause this condition. It is autosomal recessive, which means a child inherits a changed copy of the gene from each parent.

GeneticNeurologicalInherited Metabolic

Also known as: 3-phosphoglycerate dehydrogenase deficiency, infantile/juvenile form; phgdh deficiency, infantile/juvenile form; phosphoglycerate dehydrogenase deficiency

Patient organizations

Rare-disease groups that can help

Source: NIH GARD · PHGDH deficiencyGARD ID 16718 · 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 PHGDH deficiency.

Explore the PHGDH deficiency blog

Explore research for PHGDH deficiency

Explore actively recruiting PHGDH deficiency studies with HealthSpark.

HealthSpark

Find actively recruiting studies for PHGDH deficiency 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

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

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