Lysosomal Storage Disorders Flashcards
Batten Disease
Autosomal recessive neurodegenerative disease caused by buildup of lipofuscins
Results in Huntington-like behavioral changes and neurodegeneration in children. Death between ages 6-teens
Gaucher Disease - Inheritance and Metabolics
- Inheritance: Autosomal recessive
- Gene: GBA
- Deficient enzyme: Glucocerebrosidase
- Excess metabolite: Glucocerebroside
- Most common disease in the Ashkenazi Jewish population!!!
Gaucher Type I
- Least severe
- Hepatosplenomegaly
- Thrombocytopenia
- Pulmonary hypertension
- Gaucher cells/bone crises
- Erlenmeyer flask deformity
- No CNS involvement
Gaucher Type II
- Most severe
- Bulbar and pyramidal signs
- Intellectual disability
- Convulsions
- Hypertonia
- Apnea
- No bone disease/crises
- Hepatosplenomegaly
- Thrombocytopenia
- Pulmonary hypertension
- Microscopic dermatologic abnormalities
- Lifespan 2-4 years
Gaucher Type III
- Intermediate phenotype
- Chronic neuropathic
- Progressive myoclonic epilepsy
- Oculomotor apraxia
- Hepatosplenomegaly
- Thrombocytopenia
- Pulmonary hypertension
- Gaucher cells/bone crises
- Erlenmeyer flask deformities
- Survival into teens and adulthood
Gaucher Treatment
Enzyme replacement therapy
- Cerezyme, VPRIV, Elelyso
- Most effective for individuals with type I
- Not effective for individuals with type II (ERT cannot cross the blood-brain barrier)
- Improves some symptoms in individuals with type III
Substrate reduction therapy
- Miglustat, eliglustat
- For individuals with type I, some type III who cannot do ERT due to allergic reaction, hypersensitivity, or poor venous access
Tay-Sachs
Inheritance: Autsomal recessive
Gene: HEXA
Deficient enzyme: Hexosaminidase A
Major features:
- Normal development up to ~6 months of age followed by progressive neurodegeneration
- Failure to achieve motor milestones/motor regression
- Loss of responsiveness
- Visual deterioriation
- Seizures
- Progressive head enlargement due to cerebral gliosis
- Recurrent infections
- Difficulties swallowing
- CHERRY RED SPOT ON OPHTHALMOLOGIC EXAM
- Average lifespan is ~2 years
Adult-onset Tay-Sachs
- NO CHERRY RED SPOT
- Slowly progressive neurodegeneration
- Progressive muscle wasting
- Dysarthria
- Fasciculations
- Cognitive dysfunction
- Dementia
- Psychiatric problems
- Psychosis
- Can be indistinguishable from progressive adolescent-onset SMA or ALS
Fabry Disease
Inheritance: X-linked
Gene: GLA
Deficient enzyme: Alpha-galactosidase
Excess metabolite: Globotriaosylceramide (GL-3)
Major features:
- Acroparathesias (pain and tingling in limbs)
- Fabry pain crises
- Angiokeratomas
- Anhidrosis/hypohidrosis
- Corneal whorl
- Left-ventricular hypertrophy
- GI problems
- Renal insufficiency
- Depression secondary to chronic pain
- FEMALES CAN BE AFFECTED
Treatment:
-Fabrazyme enzyme replacement therapy
Krabbe Disease
Inheritance: Autosomal recessive
Gene: GALC
Deficient enzyme: Galactosylceramidase
Excess metabolite: Psychosine
Major features:
- Normal appearance at birth
- Symptom onset at 3-6 months
- Irritability
- Fevers
- Stiffening of limbs
- Seizures
- Feeding difficulties/vomiting
- Mental and motor delay
- Muscle weakness
- Spasticity
- Deafness
- Optic atrophy and blindness
- Paralysis
- Death by age 2
Mucopolysaccharidosis (MPS) Inheritance and Metabolics
Inheritance: Autosomal recessive, X-linked
Gene: Many, type-specific
Excess metabolite: Glycosaminoglycans (GAGs)
MPS Type I
Hurler Syndrome (Milder form called Hurler-Sheie)
- Developmental delay
- Intellectual disability
- Regression
- Hepatosplenomegaly
- Skeletal anomalies
- Short stature
- Cardiac anomalies
- Corneal clouding (doesn’t affect vision)
- Coarse facial features
- Hearing loss
MPS Type II
Hunter Syndrome (X-linked)
- Developmental delay
- Intellectual disability
- Regression
- Skeletal anomalies
- Short stature
- Cardiac anomalies
- CLEAR CORNEAS
- Coarse facial features
- Hearing loss
MPS Type III
San-Filippo Syndrome
- Milder skeletal phenotype
- Coarse facial features
- Progressive sleep and behavioral problems
- NO CARDIAC ANOAMLIES
- CLEAR CORNEAS
MPS Type IV
Morquio Syndrome
- Severe skeletal phenotype
- Short-trunked dwarfism
- NORMAL INTELLECT
- Chest deformities
- Cardiac anomalies
- Bone malformation
- Macrocephaly