Flashcards in Biochemistry Deck (556)
Define inherited metabolic disorder
Metabolism disorder caused by mutation in gene that codes for enzyme resulting in enzyme deficiency and breakdown of metabolic pathway
What are the 6 clinical presentations in neonates of IEMs and 5 in young children?
4. Poor feeding
5. Breathing disorder
6. Abnormal tone
1. Recurring vomiting
2. Dysmorphic features: characteristic facial expression
3. Mental retardation
5. Developmental delay: milestones
What are the 7 categories of IEMs?
1. AA metabolism disorders
2. Carbohydrate metabolism disorders
3. FAO disorders
4. Lysosomal storage disorders
5. Peroxisomal disorders
6. Urea cycle disorders
7. Mitochondrial disorders
What is Von Gierke's disease?
IEM characterised by deficiency of glucose-6-phosphatase
Renders glycogen stores of body inaccessible
Lack free glucose
Glucose synthesis from glucose-6-phosphate via gluconeogenesis hampered
What are the affects of Von Gierke's disease?
2. Lactic acidosis
Deficiency of galactose-1P uridyltransferase
Converts galactose-1P to glucose-1P which is subsequently converted to 6P and enters glycolysis
What are the effects of galactosaemia?
Child unable to utilise galactose component of lactose in milk
Accumulation of galactose-1P in blood, diarrhoea, vomiting, mental retardation, develop cataracts
What is the result of a deficiency of liver fructokinase or fructose-1P aldolase?
Fructokinase: convert fructose to fructose-1P
Fructose-1P aldolase: fructose-1P to glyceraldehyde
Results in an accumulation of fructose-1P which inhibits both glycogenolysis and gluconeogenesis leading to hypoglycaemia
What are 2 AA metabolism disorders?
Alkaptonuria: black urine
Maple syrup urine disease
Defect in breakdown of tyrosine and phenylalanine
Causes accumulation of homogentisic acid which is excreted in urine and oxidises on standing giving urine black colour
This can lead to arthritis due to build up in cartilage
Describe maple syrup urine disease
Defect in branched AA metabolism causing accumulation of keto-acids in urine
If left unmanaged can lead to physical and mental retardation
Defect in phenylalanine hydroxylase causes impaired conversion of phenylalanine to tyrosine
Phenylalanine accumulates in blood and excreted in urine (aminoaciduria)
What are the signs of phenylketonuria?
Red. melanin formation
What are the 6 presentations of phenylketonuria?
1. Mental retardation
3. Developmental delay
4. Musty odour
What is familial hypercholesterolaemia?
Disorder caused by red. number functional LDL receptors in liver