[An overview of neurometabolic diseases in Tunisia. a 3-year prospective study]

Neurometabolic diseases are a large group of genetic diseases. In our country, the diagnostic and therapeutic approach to theses diseases is rather difficult. The aim of our study was to determine the frequency of neurometabolic diseases in the hospital population, to describe the problems in diagnosing these conditions and difficulties encountered during patient care. Our goal was to propose guidelines for a practical diagnostic and therapeutic approach to neurometabolic disorders in our country.

We have conducted a prospective study over a 3-year period including all patients diagnosed with "metabolic disease" and followed at the Child and Adolescent Neurology Department of the National Institute of Neurology of Tunis.

One hundred and thirty-six patients were included (2.4% of our patients). Mean age was 7.3 +/- 5.1 years. Mean age at onset was 4.3 years. There was a high consanguinity rate. Respiratory chain defects were the most frequently suspected diseases (16.9%), followed by lysosomal diseases (8.8%). Chromatography, initially systematically prescribed, became targeted with a higher diagnostic efficacy. Metabolic diseases diagnosed as certain, represented 22% of the studied cases. This can be explained by the insufficiency of available laboratory tests of confirmation. The prescription of specific treatment was insufficient, even for confirmed pathologies (14.7%) because of the high cost of these therapies.

The diagnostic approach has to be rational, targeted, multidisciplinar and conducted within a care network. Diagnostic priority should focus on treatable neurometabolic diseases. The establishment of a systematized registry and neonatal screening for the main treatable neurometabolic diseases constitute the final objective of our work to prepare for biochemical and genetic studies.