# Type I Sialidosis in a Chinese family: a case report and literature review

## TL;DR

A Chinese family with a rare genetic disorder called type I sialidosis is reported, highlighting the role of gene sequencing in diagnosis and genetic counseling.

## Contribution

The report provides a new case of type I sialidosis in a Chinese family with a specific NEU1 mutation and emphasizes the importance of genetic testing.

## Key findings

- Three siblings were diagnosed with type I sialidosis due to a homozygous NEU1 mutation (c.544A > G).
- Antiseizure medications were used, but seizures persisted despite treatment.
- Genetic sequencing confirmed the diagnosis and aided in genetic counseling for the family.

## Abstract

Sialidosis is an autosomal recessive hereditary disease characterized by the mutation of neuraminidase-1 (NEU1) gene, resulting in decreased activity of α-N-acetylneuraminidase. This leads to metabolic abnormalities in various organs. Sialidosis is classified into two distinct clinical phenotypes, type I and type II, based on the age of onset and severity of clinical manifestations.

Here, we report a case involving a patient and his two sisters, all of whom showed seizures and ataxia during adolescence, with progressively worsening symptoms. Prior to admission, none of the patients had received a systemic diagnosis or treatment. The whole exome sequencing identified a homozygous NEU1 mutation (NM_000434.3:c.544A > G [p.Ser182Gly]) in all three siblings. Their parents and children, who were asymptomatic, were found to be heterozygous carriers. The three patients were ultimately diagnosed with type I sialidosis and treated with antiseizure medications, but they continued to experience recurrent seizures.

This case report enhances our understanding of sialidosis, particularly in patients presenting with seizures and ataxia. Furthermore, the gene sequencing is a crucial tool for confirming the diagnosis of sialidosis and provides a valuable approach for genetic counseling in affected families.