Lipid Storage diseases

Lipide storage myopathies:

  • Carnitine deficiency
  • Carnitine palmityl transferase II deficiency

 

Carnitine deficiency:

Diagnosis:

There are various forms:

  • Muscle carnitine deficiency
  • Systemic carnitine deficiency
  • Secondary carnitine deficiency

Muscle carnitine deficiency:

  • Low muscle carnitine levels. Normal systemic carnitine levels
Muscle biopsy:
  • Vacuolar myopathy. Lipid droplets in type 1 fibres.

Systemic carnitine deficiency:

Systemic carnitine levels: low
Secondary carnitine deficiency:
Secondary to liver disease, hemodialysis, mitochondrial myopathy, Valproate VPA therapy
 

Carnitine palmityl transferase II a.k.a. carnitine palmitoyltreansferase II deficiency:

Clinical features:

Commonest form: Myoglobinuria after prolonged effort. Hyperlipidemia might occur
Childhood: fasting induced hypoglycemia, hepatic failure, cardiomyopathy, peripheral neuropathy

Muscle biopsy:

Normal between episodes of rhabdomyolysis
During myoglobinuric episodes: vacuoles, necrotic fibres
Oil red O: Lipid storage in some patients.
Toluidine blue: pale green vacuoles
Testing for enzyme deficiency in: muscle, leukocytes, cultured fibroblasts

Genetics:

Autosomal recessive, chr. 1p32
 

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