Amino Acid Disorder Flashcards by juhee lee

[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%)

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[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

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[Met/AAD/PKU]

Target phenylalanine concentration in management for phenylalanine hydroxylase deficiency?

2-6 mg/dL (120 - 360 mmol/L)

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[Met/AAD/PKU]

Dietary agents to avoid in phenylalanine hydroxylase deficiency other than Phe restriction? (2)

Aspartame
Artificial sweetener that contains phenylalanine

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[Met/AAD/PKU]

Other cause of pheynylketonuria than phenylalanine hydroxylase deficiency?

Tetrahydrobiopterin (BH4) deficiency

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[Met/AAD/PKU]

Newborn screening measures ___, ___ and ___ ratio for phenylketonuria

Phenylalanine and Tyrosine, the ratio

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[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

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[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

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[Met/AAD/PKU]

Brain MRI finding shows ___
Mechanism is because ___

Progressive white matter disease (without neurologic deterioration)

Phe prevents myelination

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[Met/AAD/PKU]

Usual Phe level in classic, untreated phenylketonuria?

> 20 mg/dL (1200 mmol/L)

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[Met/AAD/PKU]

Complications due to restricted diet in phenylketonuria? (2)

Osteopenia
Vitamin B 12 deficiency

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[Met/AAD/PKU]

Cofactor that can be treated with in phenylketonuria?

Sapropterin (B6BH4, Kuvan)

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[Met/AAD/PKU]

Highest prevalent population for phenylalaine hydroxylase deficiency?

Turks 1:2,600
Irish 1:4,500

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[Met/AAD/PKU]

Biochemical process that BH4 involved other than Phenylalanine? (3)

Catecholamine
Serotonin
Nitric oxide

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[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

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[Met/AAD/PKU]

Foods that high in Phenylalanine?

Meat, beans, tofu, milk, pasta, sweat potatos

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[Met/AAD/PKU]

Phenylalanin level for mild hyperphenylalaninemia (HPA)?

Phe on unrestricted diet between 2 and 10 mg/dL

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[Met/AAD/Tyrosinemia]

Types of tyrosinemia? (3)

Hereditary tyrosinemia type 1 (hepatorenal tyrosinemia)
Tyrosinemia type 2 (oculocutaneous tyrosinemia)
Tyrosinemia type 3

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[Met/AAD/Tyrosinemia]

Causes of elevated tyrosine other than enzyme defects? (3)

Transient tyrosinemia (Infancy, delayed maturation)
Scurvy
Liver diseases

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[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

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[Met/AAD/Tyrosinemia]

Treatment for Tyrosinemia type I? (2)

Nitisinone (Orfadin)
Low-tyrosine diet

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[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)

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[Met/AAD/Tyrosinemia]

Tyrosinemia type 1

Enzyme defect?
Causal gene?

Study These Flashcards

Fumarylacetoacetase (FAH)
FAH

[Met/AAD/Tyrosinemia]

Biochemical tested in newborn screening for tyrosinemia type 1?

Study These Flashcards

Succinylacetone

# [Met/AAD/Tyrosinemia] Enzyme defect in tyrosinemia type 2?

Tyrosine aminotransferase

# [Met/AAD/Tyrosinemia] Clinical findings of tyrosinemia type 2? (3)

1. Corneal ulcers or dendritic keratitis 2. Red papular or keratotic lesions on their palms and soles (due to tyrosine buildup) 3. Intellectual disability (No liver toxicity, no succinylacetone)

# [Met/AAD/Tyrosinemia] Enzyme defect in tyrosinemia type 3?

4-hydroxyphenylpyruvate dioxygenase

# [Met/AAD/Alkaptonuria] Enzyme defect in alkaptonuria?

Homogentisate 1,2-dioxygenase

# [Met/AAD/Alkaptonuria] Three major features of alkaptonuria?

Urine that turns dark on standing Ochronosis (bluish-black pigmentation in connective tissue) Arthritis of the spine and larger joints

# [Met/AAD/Alkaptonuria] Other manifestations of alkaptonuria other than classic triad; dark urine, ochronosis, and arthritis? (3)

1. Hypothyroidism 2. Aortic or mitral valve calcification or regurgitation, aortic dilatation 3. Renal stones, prostate stones

# [Met/AAD/MSUD] Typical presentation of classic maple syrup urine disease by hours/days? 12-24 hours: ___ 2-3 days: ___ 4-6 days: ___ 7-10 days: ___

12 - 24 hours: Elevated concentrations of branched-chain amino acids and alloisoleucine 2 - 3 days: Early and nonspecific signs of metabolic intoxication (i.e., irritability, hypersomnolence, anorexia) Branched-chain alpha-ketoacids, acetoacetate, and beta-hydroxybutyrate in urine 4 - 6 days: Worsening encephalopathy manifests as lethargy, apnea, opisthotonos, and reflexive "fencing" or "bicycling" movements The sweet maple syrup odor becomes apparent in urine 7 - 10 days: Severe intoxication culminates in critical cerebral edema, coma, and central respiratory failure

# [Met/AAD/MSUD] Clinical presentation of intermediate maple syrup urine disease?

Severe metabolic intoxication and encephalopathy in the face of sufficient catabolic stress

# [Met/AAD/MSUD] Treatment for maple syrup urine disease?

BCAA-free medical foods, Judicious supplementation with isoleucine and valine

# [Met/AAD/MSUD] Clinical complications of treated adolescent/adult with maple syrup urine disease?

Attention-deficit/hyperactivity disorder, depression, and anxiety disorders

# [Met/AAD/MSUD] Maple syrup urine disease Enzyme defect? Causal gene (2)?

Branched-chain alpha-ketoacid dehydrogenase complex (BCKD) BCKDHA and BCKDHB (Branched Chain Ketoacid DeHydrogenase)

# [Met/AAD/GA] Two types of glutaric acidemia type 1?

1. Infantile-onset disease 2. Later-onset disease (after age 6 years)

# [Met/AAD/GA1] Glutaric acidemia type 1 Enzyme defect? Causal gene?

Glutaryl-CoA dehydrogenase GCDH

# [Met/AAD/GA1] Biochemical finding in newborn screening for glutaric acidemia type 1?

Glutarylcarnitine (C5DC)

# [Met/AAD/GA1] Follow-up biochemical testing for abnormal newborn screening result for glutaric acidemia type 1? (2)

Urine organic analysis or Quantitative glutaric and 3-hydroxyglutaric acid

# [Met/AAD/GA1] Clinical finding in untreated infantile type glutaric acidemia type 1? (3)

Progressive macrocephaly Generally normal development until crisis (febrile illness) Acute encephalopathic crisis (hypotonia, loss of motor skills, feeding difficulty, and sometimes seizures) usually occurring in the setting of an intercurrent infectious illness, fasting, or other physiological stressor

# [Met/AAD/GA1] Clinical finding in untreated late onset type glutaric acidemia type 1?

Nonspecific neurologic abnormalities including headaches, vertigo, dementia, and ataxia

# [Met/AAD/GA1] Characteristic brain MRI finding for glutaric acidemia type 1? (4)

1. Open opercula 2. Ventriculomegaly 3. Attenuated signal from basal ganglia (striatal degeneration) 4. Subdural hemorrhage (or retinal hemorrhage)

# [Met/AAD/GA1] Causal gene for glutaric acidemia type 1?

GCDH (Glutaryl-CoA DeHydrogenase)

# [Met/AAD/GA1] Management for glutaric acidemia type 1? (2)

Low-lysine diet Carnitine supplementation

# [Met/AAD/Homocystinuria] Classic homocystinuria Synonym? Causal gene?

Homocystinuria Caused by Cystathionine Beta-Synthase Deficiency CBS (Cystathionine b-Synthase)

# [Met/AAD/Homocystinuria] Two phenotypes of classic homocystinuria (homocystinuria Caused by Cystathionine Beta-Synthase Deficiency)?

B6-responsive homocystinuria B6-non-responsive homocystinuria

# [Met/AAD/Homocystinuria] Four characteristics of classic homocystinuria (homocystinuria Caused by Cystathionine Beta-Synthase Deficiency)?

Involvement of the eye (ectopia lentis and/or severe myopia) Skeletal system (marfanoid, excessive height, long limbs, scolioisis, and pectus excavatum) Vascular system (thromboembolism) CNS (developmental delay/intellectual disability)

# [Met/AAD/Homocystinuria] Biochemical findings of homocystinuria?

Increased concentrations of plasma total homocysteine and methionine

# [Met/AAD/Homocystinuria] Management for classic homocystinuria? (5)

Methionine-restricted diet Vitamin B6 (pyridoxine) therapy (if shown to be B6 responsive) Folate Vitamin B12 supplementation Betaine therapy (adolescent and adults)

# [Met/AAD/NKH] Enzyme defect for nonketotic hyperglycemia?

Deficient activity of the glycine cleavage enzyme system (GCS)

# [Met/AAD/NKH] Two types of nonketotic hyperglycemia?

Severe NKH (no developmental progress and intractable epilepsy) Attenuated NKH (variable developmental progress and treatable or no epilepsy)

# [Met/AAD/NKH] Characteristics of nonketotic hyperglycemia? (2) - In utero - Neonate

Hiccups in utero Progressive lethargy evolving into profound coma and marked hypotonia in the neonatal period

# [Met/AAD/NKH] Characteristic Biochemical finding for nonketotic hyperglycemia?

Increased ratio of CSF glycine to serum glycine

# [Met/AAD/NKH] Treatment option for nonketotic hyperglycemia?

Sodium benzoate

# [Met/AAD/Alkaptouria] [Amino Acid - Alkaptonuria] Name for bluish-black pigmentation in connective tissue in Alkaptonuria?

Ochronosis

# [Met/AAD/PKU] Age of onset of untreated classic phenylketonuria?

Normal at birth Within a few months musty smell and seizure

# [Met/AAD/PKU] Fetal exposure to uncontrolled Phenylketouria pregnant patients (5)?

1. Intrauterine growth restriction 2. microcephaly / brain malformations 3. congenital heart defect 4. limb malformations 5. tracheoesophageal fistula

Amino Acid Disorder Flashcards

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