Aminoacidopathies Quiz
16 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are aminoacidopathies?

A class of inherited errors of metabolism involving enzyme defects inhibiting the body's ability to metabolize certain amino acids.

What is the cause of phenylketonuria (PKU)?

Phenylalanine hydroxylase (PAH) deficiency.

What is the estimated occurrence of phenylketonuria?

1 in every 15,000 births.

What are the consequences of lacking the enzyme phenylalanine hydroxylase in phenylketonuria?

<p>Elevated phenylalanine levels, usually greater than 1,200 μmol/L.</p> Signup and view all the answers

What are the consequences of phenylalanine hydroxylase (PAH) deficiency in phenylketonuria?

<p>Disruption in the normal conversion of phenylalanine to tyrosine.</p> Signup and view all the answers

What are some examples of aminoacidopathies?

<p>Phenylketonuria (PKU), tyrosinemia, alkaptonuria, maple syrup urine disease (MSUD), isovaleric acidemia, homocystinuria, citrullinemia, arginosuccinic aciduria, and cystinuria.</p> Signup and view all the answers

What is the characteristic odor of urine in patients with PKU?

<p>Musty odor</p> Signup and view all the answers

What is the goal of PKU treatment in terms of maintaining blood levels of phenylalanine?

<p>2-10 mg/dL or 120-160 μmol/L</p> Signup and view all the answers

What is the first drug approved by the US FDA to help manage PKU?

<p>Kuvan (sapropterin dihydrochloride)</p> Signup and view all the answers

What is the sensitivity range of the Guthrie Bacterial Inhibition Test for PKU?

<p>180 to 240 μmol/L (3 to 4 mg/dL)</p> Signup and view all the answers

What is the significance of tetrahydrobiopterin in PKU?

<p>It is a co-factor in the enzymatic hydroxylation of phenylalanine, tryptophan, and tyrosine</p> Signup and view all the answers

What is the range of phenylalanine levels in patients with Non-PKU mild hyperphenylalaninemia?

<p>180-600 μmol/L</p> Signup and view all the answers

How can brain damage be avoided in PKU patients?

<p>By detecting the disease at birth and maintaining the infant on a diet containing low levels of phenylalanine</p> Signup and view all the answers

What is the purpose of the Ferric Chloride Tube Test for PKU?

<p>To detect a permanent blue-green coloration in the urine sample when treated with ferric chloride reagent</p> Signup and view all the answers

What is the main cause of elevated blood levels of phenylalanine in PKU?

<p>Deficiency in the enzymes needed for the synthesis of tetrahydrobiopterin</p> Signup and view all the answers

What is the prevalence of cases of elevated phenylalanine levels that are not the result of the lack of the PAH enzyme?

<p>1% to 5% of all cases of elevated phenylalanine levels</p> Signup and view all the answers

Study Notes

Aminoacidopathies

  • Aminoacidopathies are genetic disorders characterized by a malfunction in the metabolism of amino acids.
  • They often result from enzyme deficiencies that lead to the accumulation of specific amino acids in the blood.

Phenylketonuria (PKU)

  • PKU is caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH), which is essential for converting phenylalanine into tyrosine.
  • Estimated occurrence of PKU is about 1 in 10,000 to 1 in 15,000 live births, varying by ethnicity and geographical location.

Consequences of PAH Deficiency

  • Lack of PAH leads to elevated levels of phenylalanine, which can cause severe neurological damage if untreated.
  • Without treatment, patients can experience developmental delays, intellectual disabilities, and behavioral problems.

Examples of Aminoacidopathies

  • Common examples include Phenylketonuria (PKU), Maple Syrup Urine Disease (MSUD), and Tyrosinemia.

Characteristic Odor of Urine in PKU

  • Patients with PKU typically have urine that smells musty or "mousy" due to the accumulation of phenylacetate.

PKU Treatment Goals

  • The primary goal of PKU treatment is to maintain blood phenylalanine levels below 6 mg/dL to prevent toxicity and neurological damage.

First Drug for PKU Management

  • Sapropterin dihydrochloride is the first drug approved by the US FDA to aid in managing PKU by enhancing the activity of the PAH enzyme.

Guthrie Bacterial Inhibition Test

  • This test has a sensitivity range of approximately 90-100% for detecting PKU in newborns.

Tetrahydrobiopterin in PKU

  • Tetrahydrobiopterin is a cofactor for PAH; its supplementation can help improve phenylalanine metabolism in some patients with PKU.

Non-PKU Mild Hyperphenylalaninemia

  • Phenylalanine levels in patients with Non-PKU mild hyperphenylalaninemia typically range from 2-6 mg/dL.

Avoiding Brain Damage in PKU Patients

  • Early diagnosis and strict dietary management can prevent brain damage in individuals with PKU.

Ferric Chloride Tube Test for PKU

  • This test helps identify the presence of phenylketones in urine, indicating problems in phenylalanine metabolism.

Main Cause of Elevated Phenylalanine Levels

  • The primary cause of elevated blood phenylalanine levels in PKU patients is the deficiency of the PAH enzyme.

Prevalence of Elevated Phenylalanine Levels

  • Elevated phenylalanine levels can also occur in cases unrelated to PAH deficiency, such as other metabolic disorders or enzyme deficiencies.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Test your knowledge on aminoacidopathies, a class of inherited errors of metabolism which inhibit the body's ability to metabolize certain amino acids due to enzyme defects. Learn about diseases like phenylketonuria (PKU), tyrosinemia, alkaptonuria, and maple syrup urine disease.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser