RESUMO
Sialidosis is a rare lysosomal storage disease caused by NEU1 gene mutation at 6p21.33. It is characterized by myoclonic, ataxia, epilepsy, and decreased vision. A pair of twins with sialidosis type 1 are reported to enrich clinicians ′ understanding of the disease, so as to improve the diagnosis and treatment. The proband was a 16-year-old male. The main symptom was intermittent limb involuntary trembling for 2 years, with paroxysmal loss of consciousness. Fundus examination showed cherry-red spots. His twin brother had similar symptoms, but the overall performance was mild. Whole exome sequencing results showed that both patients carried compound heterozygous mutations of c.239C>T (p.P80L) and c.803A>G (p.Y268C) in NEU1 gene, which were from their normal phenotype mother and father.