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540

Define inherited metabolic disorder

Metabolism disorder caused by mutation in gene that codes for enzyme resulting in enzyme deficiency and breakdown of metabolic pathway

541

What are the 6 clinical presentations in neonates of IEMs and 5 in young children?

1. Vomiting
2. Seizures
3. Irritability
4. Poor feeding
5. Breathing disorder
6. Abnormal tone

1. Recurring vomiting
2. Dysmorphic features: characteristic facial expression
3. Mental retardation
4. Seizures
5. Developmental delay: milestones

542

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

543

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

544

What are the affects of Von Gierke's disease?

1. Hypoglycaemia
2. Lactic acidosis
3. Hepatomegaly

545

Describe galactosaemia

Deficiency of galactose-1P uridyltransferase
Converts galactose-1P to glucose-1P which is subsequently converted to 6P and enters glycolysis

546

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

547

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

Fructose intolerance
Results in an accumulation of fructose-1P which inhibits both glycogenolysis and gluconeogenesis leading to hypoglycaemia

548

What are 2 AA metabolism disorders?

Alkaptonuria: black urine
Maple syrup urine disease

549

Describe alkaptonuria

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

550

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

551

Describe phenylketonuria

Defect in phenylalanine hydroxylase causes impaired conversion of phenylalanine to tyrosine

Phenylalanine accumulates in blood and excreted in urine (aminoaciduria)

552

What are the signs of phenylketonuria?

Irritability
Vomiting
Mental retardation
Red. melanin formation

553

What are the 6 presentations of phenylketonuria?

1. Mental retardation
2. Hypopigmentation
3. Developmental delay
4. Musty odour
5. Autism
6. Epilepsy

554

What is familial hypercholesterolaemia?

Disorder caused by red. number functional LDL receptors in liver

555

What are the 3 effects of hypercholesterolaemia and treatment options?

1. Premature coronary heart disease
2. Tendon xanthomas
3. Severe hypercholesterolaemia

Modify diet, fibrates, statins, bile acid binding resins