Canavan's disease is a genetic neurodegenerative disease, prevalent among Ashkenazi Jews. This term defines the descendants of the Jewish communities that settled in the Reno valley during the Middle Ages. Among the latter, the incidence is 1 case for every 6,400-13,500 newborns, if both parents are Ashkenazi Jews. In the rest of the population, however, the incidence is 1 case for every 100,000 newborns.
The pathology has two forms.
- mild form, which only causes a slight delay in development and occurs during childhood. It is the rarest form.
- Severe form, which causes leukodystrophy, macrocephaly and a marked delay in development. It is the most widespread form of the disease and manifests itself in the neonatal period or in childhood.
Children suffering from severe form present neurological damage and high concentrations of N-acetyl-L-aspartic acid (NAA). High levels of acid can be found in urine, blood and cephaloracidian fluid. All this leads to a serious delay in development. In contrast, in the mild form the levels of the substance are much lower and the delay is also lower.
Canavan disease is linked to mutations in the ASPA gene, which encodes the enzyme aspartoacylase. The mutations are many and can cause both the decrease and the cancellation of the enzymatic activity. Many Ashkenazi Jews have two genetic mutations in particular. Furthermore, those with mild form tend to have a mild and severe mutation.
The prognosis varies depending on the form of the disease. Children who suffer from severe form have an average survival of about 10 years. Those who suffer from the mild form, on the other hand, have an expectation of normal life.