Glycogen Storage Disorder Flashcards
Von-Gierke Disease (Glycogen Storage Disease Type I
Inheritance: Autosomal recessive
Gene: G6PC
Deficient enzyme: Glucose-6-phosphatase
Von-Gierke Disease (Glycogen Storage Disease Type I
Major features
- Hypoglycemia
- Hyperlipidemia
- Hyperuricemia
- Lactic acidosis
- Liver dysfunction/Hepatomegaly
- Developmental delay
- Seizures
- GI problems
- Growth retardation
- Renal problems/kidney stones
GSD I, Treatment
Treatment: • Avoid fasting/maintain normal glucose to avoid hypoglycemia o Body cannot utilize glycogen, so when it is made it builds up in the liver and kidneys • Nighttime glucose infusions to avoid • Cornstarch between meals • Complex carbs • High protein/fat diet • Liver transplant for severe cases
Pompe Disease (Glycogen Storage Disease Type II)
Inheritance: Autosomal recessive
Gene: GAA
Deficient enzyme: Alpha-glucosidase
Pompe: Infatile onset:
- Cardiomegaly
- Hypotonia
- Cardiomyopathy
- Respiratory distress
- Recurrent respiratory infections
- Enlarged tongue
- Death in 1st year of life if untreated
Pompe, Late onset
•Slowly progressive proximal muscle weakness
oCan mimic limb-girdle muscular dystrophy
•Hypotonia
•Impaired cough
•Delayed motor milestones
•Dysphagia
Pompe, Treatment
Treatment:
•Myozyme ERT for infantile onset
•Lumizyme ERT for late onset
McArdle Disease (Glycogen Storage Disease Type V)
Inheritance: Autosomal recessive
Gene: PYGM
Deficient enzyme: Myophosphorylase
McArdle Disease (Glycogen Storage Disease Type V Major features/Treatment
Major features: •Myoglobinuria •Myopathy •Skeletal muscle weakness •Exercise intolerance •Rhabdomyolysis
Treatment:
•Vitamin B6 supplementation
•Sucrose supplementation before exercise
•High protein/fat diet
General Features of Galactosemias
Inheritance: Autosomal recessive Common features: •Liver dysfunction •Renal dysfunction •Hypoglycemia •Cataracts •Dairy intolerance •Lactic acidosis •Hyperuricemia •Symptom onset can sometimes be after first feeding/before NBS screen results return
GALT/Gal-1-P Deficiency
Deficient enzyme: Galactose-1-phosphate uridyl transferase
Gene: FOXO3
•Duarte allele – p.N314D
o Common, much milder manifestation, attenuation of Gal-1-P rather than depletion
GALT/Gal-1-P Deficiency: Major Features/Treatment
•Neonatal onset •NO AVERSION TO GALACTOSE CONTAINING FOODS •Hyperbilirubinemia •Liver dysfunction •Renal tubular acidosis •Intellectual disability •Developmental delay •Cataracts •Sepsis •POF Treatment •Dietary lactose restriction •Calorie supplementation •Non-dairy protein supplementation o AVOID LEGUMES
GALK Deficiency
Deficient enzyme: Galactokinase
Major features:
•Cataracts are only symptom
Treatment:
•Dietary lactose restriction
GALE Deficiency
Deficient enzyme: Galactose empirase Major features: •Severe onset •Psychomotor retardation •Hyperbilirubinemia •Liver dysfunction •Renal tubular acidosis •Intellectual disability •Developmental delay •Cataracts •Sepsis
Treatment:
•Dietary lactose and galactose restriction
