L15- Inborn Errors of Metabolism

Question 1

Accumulation of a toxin can cause disease…What can hyperammonaemia toxicity cause?

Answer 1

Clinical effects of acute hyperammonaemia toxicity

• lethargy
• poor feeding
• vomiting
• tachypnoea
• convulsions
• coma
• death

Question 2

What is acute porphyria ?

Answer 2

rare autosomal dominant metabolic disorder affecting the production of heme, the oxygen-binding prosthetic group of hemoglobin.

Question 3

What defects of Fatty acid oxidation lead to?

Answer 3

Energy Deficiencies

Question 4

What does the Basic urine metabolic screen (Leeds) look for?

Answer 4

Spot tests

Organic acids

Amino acids

Sugar Chromatography

Oligosaccharides/Sialic Acids

Mucopolysaccharides

Question 5

Homocystinuria

Answer 5

inherited disorder of the metabolism of the amino acid methionine

Often involving the enzyme Cystathionine beta-synthase (CBS)

Question 6

What are the Clinical Problems of Homocystinuria?

Answer 6

Mental retardation

Marfinoid habitus (long limbs, arachnodactyly, and hyperlaxity)

Ectopia lentis (displacement or malposition of the lens of the eye)

Osteoporosis

Thromboembolism

Question 7

Why are organic acids important in metabolic pathways?

Answer 7

Small MW organic acids are intermediates in most metabolic pathways

Question 8

Benefits of diagnosis

Answer 8

Treatment, improve prognosis

Identify cause of clinical problem

Genetic counselling

IEM (inborn errors of metabolism) act as models for other disorders

Question 9

What can Pre natal screening test for?

Answer 9

Neural tube defects

Down syndrome