Personalized Prevention in Mercury-Induced Amyotrophic Lateral Sclerosis: A Case Report

Nicola Magnavita,Francesco Chirico,Mario Sabatelli,Egeria Scoditti

doi:10.3390/app10217839

Abstract

Chronic exposure to low levels of mercury is involved in the development of motor neuron diseases (MND). Genetic alterations may have a crucial role in the onset and progression. We presented a case of a TANK-binding kinase 1 (TBK1)-mutated 54-year-old male worker who developed a MND due to chronic mercury exposure at work. He was employed in a chlor-alkali plant in Central Italy. After two years of employment he had acute mercury intoxication with suggestive neurological symptoms and a high urinary level of the metal. Through years, many episodes of intoxication occurred, but he continued to perform the same job and be exposed to mercury. After yet another episode of intoxication in 2013, he showed fasciculations of the upper limbs and trunk, and electromyographic activity patterns were consistent with amyotrophic lateral sclerosis (ALS). In 2016, a genetic test revealed a mutation of TBK1, an ALS-related gene. This case highlights the important role of genetics in personalized occupational medicine. Occupational physicians should use genetic tests to identify conditions of individual susceptibility in workers with documented frequent episodes of mercury intoxication recorded during health surveillance programs to customize prevention measures in the workplace and act before damage appears.

Highlights

Mercury (Hg) is a naturally occurring toxic heavy metal [1,2] and a global pollutant [3].Occupational exposure to elemental inorganic mercury may cause neurological and other adverse effects in exposed workers [4,5,6]
Even if its neurotoxic effects have been known for more than 300 years [7], occupational exposure may still be relevant in certain activities such as mining and metal working [8,9,10], production and waste of fluorescent lamps [11,12] and incinerators [13,14], recycling [15,16], concrete processing [17], battery production [18], thermometer and precision instrument manufacturing [19], dental care [20], and other industrial activities
We reported the case of a worker exposed to Hg in a chlor-alkali plant, who presented several episodes of work-related neurotoxicity and, developed amyotrophic lateral sclerosis (ALS)

Summary

Introduction

Mercury (Hg) is a naturally occurring toxic heavy metal [1,2] and a global pollutant [3]. Occupational exposure to elemental inorganic mercury may cause neurological and other adverse effects in exposed workers [4,5,6]. Huge differences in the onset and severity of neurological symptoms in individuals with a comparable level of exposure to Hg have been reported This points up the role of the underlying genetic factors that may modify Hg uptake, biotransformation, distribution, and elimination, and, as a result, the effective dose, i.e., the dose that produces a biological response [38]. Through the years, several epigenetic and genetic characteristics have been associated with Hg neurotoxicity [39] In this short paper, we reported the case of a worker exposed to Hg in a chlor-alkali plant, who presented several episodes of work-related neurotoxicity and, developed ALS. Genetic tests showed that he had a TANK-binding kinase 1 (TBK1) mutation

Case Presentation

Findings

Discussion

Conclusions