A polymerase chain reaction-based genotyping assay for detecting a novel Sandhoff disease-causing mutation

Area of Science:

• Genetics and Genetic Disorders
• Molecular Biology
• Biochemistry

Background:

• Sandhoff disease is a rare, fatal neurodegenerative lysosomal storage disorder.
• A specific community in northern Saskatchewan exhibits a disproportionately high incidence of Sandhoff disease.
• The genetic cause of Sandhoff disease in this population remained previously undescribed.

Purpose of the Study:

• To identify the novel mutation responsible for Sandhoff disease in the affected Saskatchewan community.
• To develop and validate a molecular diagnostic assay for detecting the identified mutation.

Main Methods:

• DNA sequencing of the HEXB gene was performed on the most recently affected patient.
• A polymerase chain reaction (PCR)-based genotyping assay was designed to detect a single-nucleotide deletion (c.115delG).
• Assay validation utilized DNA from newborn screening cards.

Main Results:

• A novel single-nucleotide deletion, c.115delG, was identified in exon 1 of the HEXB gene.
• This mutation was present in four patients exhibiting clinical symptoms of Sandhoff disease.
• The developed PCR assay reliably detected the c.115delG mutant allele.

Conclusions:

• A novel HEXB mutation (c.115delG) has been identified as the cause of Sandhoff disease in this Saskatchewan community.
• A validated PCR-based assay can accurately detect this specific mutation.
• The findings support the potential implementation of a targeted Sandhoff disease screening program for this population.