Disorders of Amino Acid Metabolism Flashcards
Oxoprolinuria
deficiency of 5 oxoprolinase enzyme
Hyperammonemia
- Def. in any of enzymes of urea cycle
- Risk inc. if block is earlier as ammonia itself accumulates
1. Respiratory alkalosis
2. Encephalopathy
3. Vomiting
4. Irritability
5. Lethargy
6. MR
Ornithine transporter deficiency
HHH 1. Hyperornithemia 2. Hyperammonemia 3. Homocitrullinuria Ornithine accumulates in cytoplasm
Ornithine transcarbamoylase deficiency
- X linked
1. Hyperammonemia
2. Aversion to high protein diet
3. High glutamine levels in CSF and blood
Argininosuccinate synthetase deficiency
- Hyperammonemia
- Citrullinemia
- Citrullinuria
- Elevated CSF citrulline levels
Hepatic coma
Acquired hyperammonemia/ Portal systemic encephalopathy
- characteristic of liver failure
- toxins bypass liver and conc. in systemic circulation inc.
1. Altered sensorium
2. Convulsions
3. Ascites
4. Jaundice
5. Hepatomegaly
6. Edema
A 6-month-old infant began to vomit occasionally and
ceased to gain weight. At 9 months of age he was readmitted to the hospital. Routine examination and laboratory analysis
were normal. After one week, he became drowsy, had fever,
pulse was elevated, and there was hepatomegaly. EEG
was done and was grossly abnormal. Blood ammonia was
elevated and urine contained high amount of glutamine
and uracil.
Hyperammonemia
OTC deficiency
Nonketotic Hyperglycemia
- defect in glycine cleavage system
- Gly levels inc. in blood, urine, CSF
1. Severe MR
2. Seizures
No effective management
Primary hyperoxaluria
- autosomal recessive
- excess production and excretion of oxalates (600mg/day)
- protein targeting defect
- Alanine glyoxylate aminotransferase usually in peroxisomes. But here, in mitochondria
- it converts glyoxalic acid to gly
- so, inc. glyoxalate and oxalates produced
1. Nephrolithiasis
2. Renal colic
3. Haematuria
Cystinuria
- Garrod’s tetrad
- autosomal recessive
- deficiency in transport of AA
- Cyanide nitroprusside test +ve
1. Abnormal excretion of cystine, arginine, lysine and ornithine
2. Crystalluria, calculi formation
3. Obstructive uropathy
Cystinosis
- widespread deposition of Cys in lysosomes
- autosomal recessive
- due to abnormal transport of Cys
Oasthouse syndrome
- malabsorption of methionine
- excrete Met, aromatic and branched AA
Cystathione beta synthase def.
- inc. plasma and urine levels of Met and HomoCys
- +ve cyanide nitroprusside test
1. MR
2. Charlie chaplin gait
2. Skeletal deformities
4. Ectopic lentis, glaucoma
5. Intravascular thrombosis
N5 N10 Methylene THFA reductase deficiency
- reduced Met syn.
- inc. HomoCys in urine
1. Behavioural changes
2. Vascular abnormalities
Cystathionuria
- Cystathione def.
- autosomal recessive
- -ve cyanide nitroprusside test
- Cystathione in urine
1. MR
2. Anaemia
3. Thrombocytopenia
4. Endocrinopathies