Deep brain stimulation for Myoclonus in sialidosis I

Sialidosis is a rare and autosomal recessive inherited disorder, caused by N-acetyl neuraminidase deficiency resulting from a mutation in the neuraminidase gene (NEU1, located on 6p21.33) [ [1] Caciotti A. Melani F. Tonin R. Cellai L. Catarzi S. Procopio E. Chilleri C. Mavridou I. Michelakakis H. Fioravanti A. d'Azzo A. Guerrini R. Morrone A. Type I sialidosis, a normosomatic lysosomal disease, in the differential diagnosis of late-onset ataxia and myoclonus: an overview. Mol. Genet. Metabol. 2020; 129: 47-58 Crossref PubMed Scopus (20) Google Scholar , [2] Han X. Wu S. Wang M. Li H. Huang Y. Sui R. Genetic and clinical characterization of mainland Chinese patients with sialidosis type 1. Mol Genet Genomic Med. 2020; 8: e1316 Crossref PubMed Scopus (5) Google Scholar ]. This isolated enzyme deficiency interrupts the normal catabolic pathways, leading to abnormal intracellular accumulation as well as urinary excretion of sialyloligosaccharides. According to the clinical manifestations, sialidosis is classified into the normomorphic type I (normomorphic or mild form) and the dysmorphic type II forms (dysmorphic or severe form). In sialidosis I (also known as cherry-red spot myoclonus syndrome), there may be an absence of any obvious physical defects and the symptoms are relatively mild and appear late. However, myoclonus is an essential feature of sialidosis I, which over the course of the disease tends to get worse and disabling. Due to the lack of effective pharmacotherapy for progressive myoclonus, it often makes the patient wheelchair bound or bedridden with limited life expectancy. In this study, we first report the use of deep brain stimulation (DBS) of globus pallidus to treat myoclonus in one sialidosis I patient. In general, the myoclonus is significantly improved after DBS. The result widens our understanding of the efficiency of DBS for the treatment of such genetic metabolic diseases, especially for the treatment of intractable myoclonus.