UP-DATE IN DIAGNOSTIC OF HEREDODEGENERATIVE ENCEPHALOPHATIES

V. Mejaški-Bošnjak

Heredodegenerative encephalopathies (HDE) are considered to be "rare diseases", but as a group they increasingly participate in morbidity and mortality of the children. This fact can be explained by increased interest for these disorders, improved diagnostics and therapeutic trials. Diagnostic of HDE relies on clinical features, progressive course of disease and multiple neurological impairement of the child. Laboratory diagnostics of HDE include negative findings of specific biochemical tests for inherited metabolic encephalopathies, as well as variety of neurophysiologic neuroimaging procedures. Localized proton magnetic resonance spectroscopy of the brain (1 H MRS) permits the analysis of brain metabolites, providing the insight to the stage of disease and main underlying pathological process e.g. (degeneration of neuro-axonal unit, demyelination, defect of brain energy metabolisam, gliosis etc.). Based on unique findings of brain 1H MRS, increasing number of HDE were defined recently:" Creatine deficiency in the brain: A new treatable inborn error of metabolism. " (Stöckler et al. 1994), "Myelinopathia centralis diffusa"-"Vanishing white matter " (Hanefeld et al. 1993, van der Knaap et al 1997). Another two entities of HDE are determined by using clinical and morphological MRI criteria i.e. "Megalencephalic leukoencephalopathy with subcortical cysts"- MLC (van der Knaap et al 1995) and "Normo-microcephalic leukoencephalopathy with temporal cysts" (Ollivier, Gärtner, 1998). Recent discovery of MLC1 gene in patients with MLC and GFAP in patients with Alexander disease permits the diagnosis of these HDE on molecular level, including prenatal diagnosis.