Nitrogen 3 - Inherited Metabolic Disorders

Question 1

What pattern of inheritance do most inherited metabolic disorders show?

Answer 1

autosomal recessive inheritance

Question 2

Give 4 examples of common clinical features of inherited metabolic disorders.

Answer 2

1. acidosis
2. vomiting, refusal of feeds, irritability
3. hypoglycaemia
4. central nervous system dysfunction

Question 3

Between what structures is the urea cycle split?

Answer 3

mitochondrial matrix and cytosol

Question 4

Where does the urea cycle (primarily) occur?

Answer 4

the liver

Question 5

What is the most common urea cycle disorder?

Answer 5

ornithine transcarbamoylase (OTC)

Question 6

What kind of pattern of inheritance does OTC have?

Answer 6

X linked inheritance

Question 7

What clinical feature characterises OTC?

Answer 7

hyperammonaemia - is a medical emergency that typically presents in newborn period

Question 8

What is one of the more common amino acid disorders?

Answer 8

phenylketoneuria (PKU)

Question 9

How is phenylketonuria treated?

Answer 9

reduced protein diet supplemented with tyrosine

Question 10

What causes PKU?

Answer 10

phenylalanine is unable to be converted to tyrosine so the toxic byproducts of the build up of phenylalanine causes problems

Question 11

How is PKU diagnosed?

Answer 11

positive screening test