Phenylketonuria: Difference between revisions

From WikiMD's Wellness Encyclopedia

CSV import
CSV import
 
Line 1: Line 1:
{{SI}}  
{{SI}}
{{Infobox medical condition
{{Infobox medical condition
| name           = Phenylketonuria
| name = Phenylketonuria
| image           = [[File:L-Phenylalanin_-_L-Phenylalanine.svg|alt=Chemical structure of phenylalanine]]
| image = [[File:L-Phenylalanin_-_L-Phenylalanine.svg|thumb|alt=Chemical structure of phenylalanine]]
| caption         = Chemical structure of [[phenylalanine]]
| caption = Chemical structure of [[phenylalanine]]
| synonyms       = PKU
| synonyms = PKU
| pronounce       =  
| pronounce =
| specialty       = [[Medical genetics]]
| specialty = [[Medical genetics]]
| symptoms       = Intellectual disability, seizures, behavioral problems, mental disorders, musty smell
| symptoms = Intellectual disability, seizures, behavioral problems, mental disorders, musty smell
| onset           = Symptoms develop gradually
| onset = Symptoms develop gradually
| duration       = Lifelong
| duration = Lifelong
| causes         = [[Genetic mutation]] in the [[PAH (gene)|PAH gene]]
| causes = [[Genetic mutation]] in the [[PAH (gene)|PAH gene]]
| risks           = Family history
| risks = Family history
| diagnosis       = [[Newborn screening]], [[blood test]]
| diagnosis = [[Newborn screening]], [[blood test]]
| differential   = [[Hyperphenylalaninemia]], [[biopterin deficiency]]
| differential = [[Hyperphenylalaninemia]], [[biopterin deficiency]]
| prevention     = [[Dietary management]]
| prevention = [[Dietary management]]
| treatment       = [[Low-phenylalanine diet]], [[sapropterin]]
| treatment = [[Low-phenylalanine diet]], [[sapropterin]]
| medication     = [[Sapropterin]], [[pegvaliase]]
| medication = [[Sapropterin]], [[pegvaliase]]
| prognosis       = Good with treatment
| prognosis = Good with treatment
| frequency       = 1 in 12,000 births
| frequency = 1 in 12,000 births
| deaths         = Rare with treatment
| deaths = Rare with treatment
}}
}}
[[File:Inborn_errors_of_metabolism_of_phenylalanine_and_tyrosine.svg|thumb|Metabolic pathway of phenylalanine and tyrosine]]
'''Phenylketonuria''' ('''PKU''') is a rare [[genetic disorder]] characterized by the inability to metabolize the amino acid [[phenylalanine]]. This condition is caused by a deficiency in the enzyme [[phenylalanine hydroxylase]], which is necessary for converting phenylalanine to [[tyrosine]].
'''Phenylketonuria''' ('''PKU''') is a rare [[genetic disorder]] characterized by the inability to metabolize the amino acid [[phenylalanine]]. This condition is caused by a deficiency in the enzyme [[phenylalanine hydroxylase]], which is necessary for converting phenylalanine to [[tyrosine]].
== Genetics ==
== Genetics ==
[[File:Autorecessive.svg|left|thumb|Autosomal recessive inheritance pattern]]
PKU is inherited in an [[autosomal recessive]] pattern, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected by the disorder. The gene responsible for PKU is located on chromosome 12.
PKU is inherited in an [[autosomal recessive]] pattern, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected by the disorder. The gene responsible for PKU is located on chromosome 12.
== Pathophysiology ==
== Pathophysiology ==
Line 43: Line 43:
* [[Inborn errors of metabolism]]
* [[Inborn errors of metabolism]]
* [[Amino acid metabolism]]
* [[Amino acid metabolism]]
* [[Genetic disorders]]
* [[Genetic disorders]]]]
[[File:Inborn_errors_of_metabolism_of_phenylalanine_and_tyrosine.svg|left|thumb|Metabolic pathway of phenylalanine and tyrosine]]
== See Also ==
== See Also ==
* [[Tyrosinemia]]
* [[Tyrosinemia]]

Latest revision as of 04:26, 14 April 2025

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's medical weight loss NYC, sleep center NYC
Philadelphia medical weight loss and Philadelphia sleep clinics

Phenylketonuria
Error creating thumbnail:
Synonyms PKU
Pronounce
Specialty Medical genetics
Symptoms Intellectual disability, seizures, behavioral problems, mental disorders, musty smell
Complications N/A
Onset Symptoms develop gradually
Duration Lifelong
Types N/A
Causes Genetic mutation in the PAH gene
Risks Family history
Diagnosis Newborn screening, blood test
Differential diagnosis Hyperphenylalaninemia, biopterin deficiency
Prevention Dietary management
Treatment Low-phenylalanine diet, sapropterin
Medication Sapropterin, pegvaliase
Prognosis Good with treatment
Frequency 1 in 12,000 births
Deaths Rare with treatment


File:Inborn errors of metabolism of phenylalanine and tyrosine.svg
Metabolic pathway of phenylalanine and tyrosine

Phenylketonuria (PKU) is a rare genetic disorder characterized by the inability to metabolize the amino acid phenylalanine. This condition is caused by a deficiency in the enzyme phenylalanine hydroxylase, which is necessary for converting phenylalanine to tyrosine.

Genetics[edit]

PKU is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected by the disorder. The gene responsible for PKU is located on chromosome 12.

Pathophysiology[edit]

In individuals with PKU, the accumulation of phenylalanine in the body can lead to a variety of health problems. High levels of phenylalanine can cause damage to the brain and nervous system, leading to intellectual disability and other neurological issues.

Clinical Features[edit]

File:NIH microcephaly.jpg
Microcephaly is a possible feature of untreated PKU

Symptoms of PKU can vary but often include intellectual disability, microcephaly, seizures, and behavioral problems. If untreated, PKU can lead to severe developmental delays and neurological complications.

Diagnosis[edit]

File:Phenylketonuria testing.jpg
Newborn screening for PKU

PKU is typically diagnosed through newborn screening programs, which test for elevated levels of phenylalanine in the blood. Early detection is crucial for preventing the adverse effects of the disorder.

Treatment[edit]

The primary treatment for PKU is a phenylalanine-restricted diet, which involves limiting the intake of foods high in phenylalanine, such as meat, dairy, and nuts. Special medical formulas and foods are often used to ensure adequate nutrition while maintaining low phenylalanine levels.

Complications[edit]

If PKU is not managed properly, individuals may experience severe intellectual disability, behavioral problems, and other neurological issues. Pregnant women with PKU must maintain strict control of their phenylalanine levels to prevent maternal PKU syndrome, which can affect the developing fetus.

Prevention[edit]

File:Phenylalanine warning for phenylketonurics.jpg
Warning label for phenylketonurics

Genetic counseling is recommended for families with a history of PKU. Prenatal testing and carrier screening can help identify at-risk pregnancies and individuals.

See also[edit]

See Also[edit]