Inborn Errors of Metabolism--Complex Molecules Flashcards
What does the peroxisome do?
Carry out oxidation reactions which result in break down of fatty acids.
What are the general features of peroxisomal disorders?
Elevated very long-chain fatty acids
Onset infant to adult
Dysmorphic features
Hypotonia
Liver disease
Seizures
Cognitive dysfunction
What are the genes that cause Zellweger syndrome?
PEX genes (AR); PEX1 most common
What is the blood test performed in Zellweger syndrome?
Very long-chain fatty acids
What are the features of Zellweger syndrome?
Feeding difficulties
Hepatosplenomegaly
Dysmorphic features
Hypotonia
Seizures
Cognitive dysfunction
*Chondrodysplasia punctata (stippling near the ends of the bones)
What is the gene responsible for X-linked Adrenoleukodystrophy?
ABCD1 (X-linked)
What are the features of X-linked Adrenoleukodystrophy (childhood onset)?
loss of vision
learning disabilities
dysphagia (difficulty swallowing)
seizures
deafness
lack of coordination and balance
fatigue
intermittent vomiting
weight loss
lack of appetite
nausea
darkening of the skin
progressive dementia
muscle weakness
low blood glucose (blood sugar)
headaches in the morning
What are the features of X-linked Adrenoleukodystrophy (adult onset)?
Adrenomyeloneuropathy
-a stiff gait when walking and bladder and bowel dysfunction.
The adrenal glands often fail to produce enough steroid (cortisol) in people who have ALD, causing Addison’s disease.
What percentage of X-linked Adrenoleukodystrophy is childhood onset?
1/3 (4-8 years)
What is the blood test for X-linked Adrenoleukodystrophy?
Very long-chain fatty acids
What is a therapy option for X-linked Adrenoleukodystrophy?
Stem cell transplant–before onset of symptoms
Is on NBS for that reason
What is the gene mutation in Gaucher?
GBA (AR)
Genotype/phenotype correlation
What is the enzyme deficient in Gaucher?
Glucocerebrosidase
What is the phenotype of Gaucher disease?
Splenomegaly (95%)
Hepatomegaly (87%)
Thrombocytopenia (50%)
Anemia (40%)
Bone marrow infiltration (38%)
Bone pain (27%)
What are the unique features of Gaucher disease Type I?
Bone disease
Hepatosplenomegaly
No CNS symptoms
What are the unique features of Gaucher disease Type 2?
CNS symptoms (seizures, brain damage), death by 4
What are the unique features of Gaucher disease Type 3?
CNS symptoms
Slower progression
Survival into 20-30s
What is the blood test for Gaucher disease?
Lyso-Gb1
Glucocerebrosidase enzyme testing
What is the treatment for Gaucher disease?
Enzyme replacement
Substrate reduction
What is the genetic cause of Fabry disease?
GLA (X-linked)
What is the phenotype of Fabry disease?
*Pain in the hands and feet
Tickling and prickling
Burning
Kidney disease
Abnormal heart rhythms
Heart enlargement
Increased stroke risk
*Sweating abnormalities
*Cataracts
*Angiokeratoma (looks like a dark red wart)
What enzyme is deficient in Fabry disease?
Alpha-galactosidase
What is the blood test in Fabry disease?
Lyso GL3
Enzyme
What is the therapy in Fabry disease?
Enzyme replacement (still some remaining organ damage)
What is the genetic cause of Pompe disease?
GAA (AR)
What is the phenotype of Pompe disease (infantile)?
*First few months of life
Hypertrophic cardiomyopathy (enlarged heart)
Skeletal muscle weakness (diaphragm and other breathing muscles)
What is the phenotype of Pompe disease (juvenile and late-onset)?
*Any age
Proximal limb weakness (shoulders and hips)
Progressive diaphragm weakness (Breathing difficulties)
*Heart NOT involved
What percentage of Pompe disease is juvenile/adult onset?
80%