Brain MRI and biological diagnosis in five Tunisians MLD patients

Abstract

Abstract: Metachromatic leukodystrophy (MLD) is a recessive autosomal disease which is characterized by an accumulation of sulfatides in the central and peripheral nervous system. It is due to the enzyme deficiency of the sulfatide sulfatase i.e. arylsulfatase A (ASA). we studied 5/200 cases of MLD and clearly distinguished three clinical forms. One of them presented the juvenile form; two presented the late infantile form; and two other presented the adult form. The Magnetic Resonance Imaging (MRI) of these patients showed a diffuse, bilateral and symmetrical demyelination. The biochemical diagnosis of MLD patients evidencing the low activity of ASA and sulfatide accumulation.

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Patients and methods: We studied 5/200 MLD patients addressed to us for behavioral abnormalities and progressive mental deterioration. All of them were diagnosed at first by brain MRI evidencing a bilateral demyelination, then the measurement of ASA activity using P-nitrocathecol sulfate as substrate, finally the sulfatiduria was performed using thin-layer chromatography using alpha-naphtol reagent.

Results: In this study, from 200 patients presenting behavioral abnormalities and a progressive mental deterioration, we reported just 2 patients were diagnosed as late-infantile form of MLD. Only1 case presented as the juvenile form; and 2 patients with the adult-type of MLD. The brain magnetic resonance imaging (MRI) of all patients showed characteristic lesions of MLD with extensive demyelination. Biochemical investigations of these patients detected a low level of ASA activity at 0°C and 37°C; the excess of sulfatide in sulfatiduria.

Conclusion: MRI is required to orient the diagnosis of MLD patients; the latter must be confirmed by the biochemical investigations which is based on the measurement of ASA activity and the excess of sulfatide showed in the sulfatiduria.