Lipid metabolism defects

Question 1

What are the pathways involved in mitochondrial fatty acid beta oxidation?

Answer 1

1. Medium chain and short chain beta oxidation
2. Long chain beta oxidation
3. Carnitine metabolism
4. Ketone synthesis

Question 2

What does primary carnitine deficiency cause?

Answer 2

cardiomyopathy

Question 3

What is the typical biochemical profile for MCAD?

Answer 3

hypoketotic hypoglycemia

Question 4

How can peroxisomal disorders be classified?

Answer 4

1. Disorders of peroxisome import (Zellweger, neonatal adrenoleukodystrophy, infantile refsum disease, rhizomelic chondrodysplasia punctata
2. Defects of single peroxisomal enzyme (i.e. XLA, peroxisomal thiolase deficiency, classic refsum disease, 2-methylacyl coa racemase deficiency, glutaric aciduria type III.

Question 5

What is the typical Zellweger syndrome look?

Answer 5

High forehead, upslanting palpebral fissures, hypoplastic supraorbital ridges, epicanthal folds.
Severe weakness and hypotonia, neonatal seizures, eye abnormalities (cataracts, glaucoma, corneal clouding, brushfield spots, pigmentary retinopathy, nerve dysplasia)

Question 6

What is infantil refsum disease?

Answer 6

Phytanic acid build up
Sensorineurla hearing loss and pigmentary degeneration of the retina
hypotonia
hepatomegaly
Moderately dysmorphic
Cholesterol, high/low density lipoprotein reduced.

Question 7

What is Rhizomelic chondrodysplasia punctata

Answer 7

Calcification within hyaline cartilate associated with dwarfing, cataracts, multiple malformations due to contractures.
Shortening of proximal limb bones, etaphyseal cupping, disturbed ossification.
Ichthyosiform erythroderma
Short and microcephaly.

Question 8

How does classic refsum disease manifest?

Answer 8

Night blindness (retinitis pigmentosa), ichthyosis, peripheral neuropathy, ataxia, occasioanl cardiac arrhythmias. Normal cognitive function.
Phytanic acid-restriction diet can reverse peripheral neuropathy.