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6-pyruvoyl-tetrahydropterin Synthase Deficiency

What is 6-Pyruvoyl-Tetrahydropterin Synthase Deficiency?

6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency is a rare disorder that results in the lack of a molecule called tetrahydrobiopterin (BH4). Lack of BH4 results in high levels of an amino acid called phenylalanine, a condition known as hyperphenylalaninemia. Phenylalanine and other amino acids are building blocks for proteins and are essential for proper growth and development. Additionally, BH4 deficiency results in very low levels of chemicals which transmit impulses from one nerve cell to another (neurotransmitters). Individuals with PTPS deficiency can have a variety of symptoms including neurological abnormalities (seizures and swallowing problems), low muscle tone (hypotonia) in the body, excess muscle tone (rigidity) in the arms and legs, loss of coordination or delayed motor development, delayed intellectual development, and temperature regulation problems. Infants with PTPS deficiency are often healthy at birth but quickly begin to show signs of failure to thrive. Additional symptoms generally appear within the first four to six months of life. A small head size (microcephaly) may also be identified in early infancy.

The symptoms of PTPS deficiency can vary widely and range from mild to severe. Twenty percent of individuals have the mild or atypical form. Individuals with the mild or atypical form of PTPS deficiency have moderate or transient alterations in phenylalanine levels and normal levels of neurotransmitters.

How common is 6-Pyruvoyl-Tetrahydropterin Synthase Deficiency?

PTPS deficiency is a rare disorder. In Caucasians, PTPS deficiency occurs in about 1 in 1,000,000 individuals, but is more frequent in East Asian populations.

How is 6-Pyruvoyl-Tetrahydropterin Synthase Deficiency treated?

Treatment of PTPS deficiency will generally focus on reducing the high phenylalanine levels by dietary intervention and normalizing the neurotransmitter levels. Treatment may include synthetic BH4 and other medications which help restore neurotransmitter levels. Patients with the severe form may need both synthetic BH4 supplementation and medications to restore neurotransmitters, while mild cases will need only BH4 supplementation.

What is the prognosis for a person with 6-Pyruvoyl-Tetrahydropterin Synthase Deficiency?

Prompt diagnosis and early treatment of PTPS deficiency is critical for reducing or preventing potentially severe, irreversible neurologic damage. Without early diagnosis and treatment, this condition is potentially life-limiting.

Resources

CLIMB (Children Living with Inherited Metabolic Diseases), 176 Nantwich Rd., Crewe, CW2 6BG United K

Patient organization for inherited metabolic diseases supports patients worldwide with over 700 inherited metabolic diseases

176 Nantwich Rd., Crewe, CW2 6BG United Kingdom http://www.climb.org.uk/
Phone: 4408452412173

Genetics Home Reference,

Provides information on genetic conditions for patients, families and medical professionals.

Phone: 888-346-3656

NORD- National Organization for Rare Diseases

Provides services and information for patients and families with rare diseases.

55 Kenosia Ave., Danbury, CT 06810
Phone: 800-999-6673

Other names for 6-pyruvoyl-tetrahydropterin Synthase Deficiency

  • Hyperphenylalaninemia, tetrahydrobiopterin-deficient, due to PTS deficiency
  • Hyperphenylalaninemia, BH4-deficient, due to partial PTS deficiency
  • Hyperphenylalaninemia, BH4-deficient, A (HPABH4A)

Counsyl has renamed its products effective July 19, 2017. The Family Prep Screen is now the Foresight Carrier Screen.

The new names now appear on all communications from Counsyl. If you have any questions, please contact Counsyl directly.

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