HOMOCARNOSINOSIS - INCREASED CONTENT OF HOMOCARNOSINE AND DEFICIENCY OF HOMOCARNOSINASE IN BRAIN

Biochemical studies were carried out on a brain biopsy obtained from a 40 y old woman with homocarnosinosis. This patient and 2 of her siblings have a progressive neurological disorder characterized by spastic paraplegia, dementia and retinal pigmentation. Homocarnosine concentrations in their CSF, as well as in the CSF of their neurologically normal mother, are elevated 20‐40‐fold. Homocarnosine content was 4 times higher in the patient's frontal cortex than in biopsied cortex from a large group of control subjects. The activity of the synthetic enzyme, homocarnosine‐carnosine synthetase. was not increased in the homocarnosinosis patient's brain. Homocarnosinase activity, however, was undetectable in the patient's brain biopsy, while it could readily be measured in comparable biopsies from control subjects. We conclude that homocarnosinase deficiency is probably inhcrited as an autosomal recessive trait, but that it is unlikely of itself to have caused the neurological syndrome affecting our patients. Copyright © 1979, Wiley Blackwell. All rights reserved