# Cellular Lyso-Gb3 Is a Biomarker for Mucolipidosis II

## TL;DR

Researchers found that a substance called Lyso-Gb3 can serve as a biomarker for mucolipidosis II/III, a rare genetic disorder, and its levels decrease with treatment.

## Contribution

Lyso-Gb3 is identified as a novel biomarker for mucolipidosis II/III, which previously lacked reliable biomarkers.

## Key findings

- Lyso-Gb3 levels are elevated in mucolipidosis II/III patient cells compared to normal cells.
- Lyso-Gb3 levels decrease after total lysosomal enzyme supplementation in mucolipidosis II/III cells.
- Lyso-Gb3 is elevated in knock-out cells of GNPTAB gene models for mucolipidosis II/III.

## Abstract

Lysosomal storage diseases are caused by defective lysosomal function, such as impaired lysosomal enzyme activities, which include more than 70 different diseases. Although biomarkers and therapies have been developed to date for some of them, many others remain challenging to diagnose and treat. In this study, an elevated level of Globotriaosylsphingosine (Lyso-Gb3), an already known biomarker for Fabry disease, was confirmed in the knock-out cells of the GLA, GNPTAB, and PSAP genes and models for Fabry, mucolipidosis II/III (ML II/III), and combined saposin deficiency, respectively. Lyso-Gb3 was high in ML II/III patient skin fibroblasts compared with normal cells and was decreased after total lysosomal enzyme supplementation. There have been no useful biomarkers reported in ML II/III until now. This study shows that Lyso-Gb3 is elevated in ML II/III patient cells and is decreased by treatment, indicating that Lyso-Gb3 is a potential biomarker for ML II/III.