URINARY-EXCRETION OF LEAD AND MERCURY AFTER ORAL-ADMINISTRATION OF MESO-2,3-DIMERCAPTOSUCCINIC ACID IN PATIENTS WITH MOTOR-NEURON DISEASE

Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are progressive neurodegenerative disorders involving motor neurones. The aetiology of the non-familial forms is still unknown but it has be en suggested that long-term exposure to heavy metals such as lead and mercury may play a role in the pathogenesis of these diseases. In 53 p atients suffering from ALS (n = 42) and SMA (n = 9) the oral administr ation of dimercaptosuccinic acid (DMSA, 20 mg/kg) did not result in a greater mobilization of lead and mercury from peripheral depots than i n control subjects. Although it cannot be excluded that the amount of lead or mercury excreted after DMSA administration may not be a reflec tion of the amount accumulated in the motor neurones, this study does not provide support for the hypothesis that heavy metals play a signif icant role in the occurrence of motor neurone diseases.