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PTS gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PTS gene

The PTS gene provides instructions for an enzyme required to produce tetrahydrobiopterin, a molecule essential for processing amino acids and creating neurotransmitters.

Normal Function

The PTS gene provides instructions for making an enzyme called 6-pyruvoyltetrahydropterin synthase. This enzyme is involved in the production of a molecule called tetrahydrobiopterin (BH4). Tetrahydrobiopterin acts as a cofactor, helping enzymes carry out critical chemical reactions in the body. It is required for the conversion of the amino acid phenylalanine into tyrosine and is essential for the production of neurotransmitters, which transmit signals between nerve cells in the brain.

Health Conditions Related to Genetic Changes

Tetrahydrobiopterin deficiency

More than 45 mutations in the PTS gene have been found to cause 6-pyruvoyltetrahydropterin synthase (PTS) deficiency, which accounts for more than half of all cases of tetrahydrobiopterin deficiency. These mutations reduce or eliminate the activity of the enzyme, leading to a shortage of tetrahydrobiopterin.

The lack of this cofactor results in two primary issues:

  • Phenylalanine buildup: Because phenylalanine cannot be converted to tyrosine, it accumulates to toxic levels in the blood and tissues, which can cause brain damage.
  • Neurotransmitter disruption: The reduction in neurotransmitter production contributes to intellectual disability and impaired brain function.

Other Names for This Gene

  • 6-pyruvoyl-H4-pterin synthase
  • 6-pyruvoyl-tetrahydropterin synthase
  • PTP synthase
  • PTPS
  • PTPS_HUMAN
  • sepiapterin synthase A
  • sepiapterin synthesizing enzyme 1

Frequently Asked Questions

Patients with PTS deficiency must follow a low‑phenylalanine diet, limiting high‑protein foods such as meat, dairy, eggs, nuts, and soy. Phenylalanine‑free medical foods and amino‑acid supplements are used to provide essential nutrients while keeping blood phenylalanine below the target range. Regular dietitian guidance is essential to balance growth needs with restriction.
Blood phenylalanine is typically monitored every 1–2 weeks during infancy and every 3–6 months once stable. The target range is usually 120–360 µmol/L (4–12 mg/dL) for most patients, but individual goals may vary based on age, treatment response, and neurologic status.
Untreated patients may experience delays in speech, motor skills, and cognitive development, and may develop intellectual disability. Early intervention with speech therapy, occupational therapy, and targeted educational support can improve outcomes, especially when combined with strict dietary control and BH4 supplementation if indicated.===
Clinicians assess the mutation’s predicted effect on protein function (e.g., missense, nonsense, splice site), review in silico pathogenicity scores, compare with known disease‑associated variants, and consider biochemical evidence such as low BH4 or high phenylalanine. Functional assays in patient cells or in vitro studies may be performed when available.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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