Amino Acid Disorder Flashcards
[Met/AAD/PKU]
Enzyme deficient in phenylketonuria?
Causal gene for phenylalanine hydroxylase deficiency?
Percentage of phenylketonuria due to phenylalanine hydroxylase deficiency?
Phenylalanine hydroxylase
PAH
98% (Tetrahydrobiopterin (BH4) deficiency 2%)
[Met/AAD/PKU]
Biochemical diagnosis of phenylalanine hydroxylase deficiency? (3)
Plasma phenylalanine > 2 mg/dL (120 mmol/L)
Abnormal ratio of phenylalanine to tyrosine (>3, normal <1)
Normal BH4 cofactor, dihydropterine reductase
[Met/AAD/PKU]
Target phenylalanine concentration in management for phenylalanine hydroxylase deficiency?
2-6 mg/dL (120 - 360 mmol/L)
[Met/AAD/PKU]
Dietary agents to avoid in phenylalanine hydroxylase deficiency other than Phe restriction? (2)
Aspartame
Artificial sweetener that contains phenylalanine
[Met/AAD/PKU]
Other cause of pheynylketonuria than phenylalanine hydroxylase deficiency?
Tetrahydrobiopterin (BH4) deficiency
[Met/AAD/PKU]
Newborn screening measures ___, ___ and ___ ratio for phenylketonuria
Phenylalanine and Tyrosine, the ratio
[Met/AAD/PKU]
Symptoms of phenylketonuria if untreated? (5)
- Skin, smell (3)
- Neurologic (2)
- Musty body order
- Eczema
- Decreased skin and hair pigmentation
- Epilepsy, Intellectual disability, behavioral problems
- Parkinson-like features
[Met/AAD/PKU]
Teratogenic effect of phenylketonuria if untreated? (6)
- Recurrent spontaneous abortion
- Microcephaly, intellectual disability, behavioral problems
- Congenital heart defect
- Tracheoesophageal fistula
- Limb malformations
- Intrauterine growth restriction
[Met/AAD/PKU]
Brain MRI finding shows ___
Mechanism is because ___
Progressive white matter disease (without neurologic deterioration)
Phe prevents myelination
[Met/AAD/PKU]
Usual Phe level in classic, untreated phenylketonuria?
> 20 mg/dL (1200 mmol/L)
[Met/AAD/PKU]
Complications due to restricted diet in phenylketonuria? (2)
Osteopenia
Vitamin B 12 deficiency
[Met/AAD/PKU]
Cofactor that can be treated with in phenylketonuria?
Sapropterin (B6BH4, Kuvan)
[Met/AAD/PKU]
Highest prevalent population for phenylalaine hydroxylase deficiency?
Turks 1:2,600
Irish 1:4,500
[Met/AAD/PKU]
Biochemical process that BH4 involved other than Phenylalanine? (3)
Catecholamine
Serotonin
Nitric oxide
[Met/AAD/PKU]
Clinical findings of Tetrahydrobiopterin (BH4) deficiency compared to PKU? (3)
- Microcephaly, epilepsy, intellectual disability, abnormal movements
- Recurrent hyperthermia without infections
- Hypersalivation, and swallowing difficulties
[Met/AAD/PKU]
Foods that high in Phenylalanine?
Meat, beans, tofu, milk, pasta, sweat potatos
[Met/AAD/PKU]
Phenylalanin level for mild hyperphenylalaninemia (HPA)?
Phe on unrestricted diet between 2 and 10 mg/dL
[Met/AAD/Tyrosinemia]
Types of tyrosinemia? (3)
Hereditary tyrosinemia type 1 (hepatorenal tyrosinemia)
Tyrosinemia type 2 (oculocutaneous tyrosinemia)
Tyrosinemia type 3
[Met/AAD/Tyrosinemia]
Causes of elevated tyrosine other than enzyme defects? (3)
Transient tyrosinemia (Infancy, delayed maturation)
Scurvy
Liver diseases
[Met/AAD/Tyrosinemia]
Clinical presentation of untreated Tyrosinemia type I? (5)
- Growth failure
- Liver dysfunction
- Renal tubular dysfuction (Fanconi like renal syndrome)
- Neurologic crises: altered mental status, abdominal pain, peripheral neuropathy, and/or respiratory failure
- Rickets
[Met/AAD/Tyrosinemia]
Treatment for Tyrosinemia type I? (2)
Nitisinone (Orfadin)
Low-tyrosine diet
[Met/AAD/Tyrosinemia]
What is Nitisinone (Orfadin)?
Synthetic reversible inhibitor of Hydroxyphenylpyruvate dioxygenase
(parahydroxyphenylpyruvic acid dioxygenase (p-HPPD), prevents the accumulation of fumarylacetoacetate and its conversion to succinylacetone)