Clinical Neurology · Child Neurology
Storage Diseases
Glycogen and lysosomal storage diseases of relevance to neurology.
Glycogen storage diseases
| Disease | Enzyme deficiency | Hypoglycemia | Hepatomegaly | Hyperlipidemia | Muscle symptoms | Mnemonic |
|---|---|---|---|---|---|---|
| von Gierke | Glucose-6-phosphatase | Yes | Yes | Yes | None | — |
| Pompe | Acid maltase (lysosomal α-1,4-glucosidase) | No | Yes | No | Muscle weakness (develops HF) | P for Pump (heart) |
| Cori | Glycogen debrancher | Yes | Yes | Yes | Myopathy | — |
| Andersen | Glycogen branching enzyme | No | Yes | No | None | — |
| McArdle | Muscle glycogen phosphorylase | No | No | No | Exercise-induced cramps | M for Muscle (glycogen phos) |
| Hers | Liver glycogen phosphorylase | Yes | Yes | No | None | H for Hepatic (glycogen phos) |
Lysosomal storage diseases
| Disease | Findings | Deficient enzyme | Accumulated substrate | Inheritance |
|---|---|---|---|---|
| Gaucher |
| Glucocerebrosidase | Glucocerebroside | AR |
| Niemann-Pick |
| Sphingomyelinase | Sphingomyelin | AR |
| Tay-Sachs |
| Hexosaminidase A | GM2 ganglioside | AR |
| Metachromatic leukodystrophy | Central and peripheral demyelination with ataxia, dementia | Arylsulfatase A | Cerebroside sulfate | AR |
| Fabry |
| α-galactosidase A | Ceramide trihexoside | XR |
| Krabbe |
| Galactocerebrosidase | Galactocerebroside | AR |
| Hurler |
| α-L-iduronidase | Heparan & dermatan sulfate | AR |
| Hunter | Mild Hurler + aggressive behavior, no corneal clouding | Iduronate sulfatase | Heparan & dermatan sulfate | XR |
Quick differentials
- Gaucher: no neurological symptoms
- Niemann-Pick & Tay-Sachs: both associated with a cherry-red spot; Niemann-Pick also has HSM
- Fabry & Krabbe: both have peripheral neuropathy. Fabry has normal development and angiokeratomas; Krabbe has developmental delay and optic atrophy
- Hurler & Hunter: Hunter is a milder form of Hurler (remember, hunters need good vision, no corneal clouding)
LIGHTS on RITE by Ahmed Koriesh