Related Experiment Video
Updated: May 2, 2026
12:31
In Vivo Modeling of the Morbid Human Genome using Danio rerio
Published on: August 24, 2013
21.2K
Experimental insights into MMACHC variants using a novel minigene system.
Yan Dong1, Xiaowei Xu2, Weiran Li3
1Clinical School of Pediatrics, Tianjin Medical University, Tianjin, China; Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin, China.
Molecular Genetics and Metabolism
|November 23, 2025
Summary
Genetic variants in the MMACHC gene cause cblC disease. This study developed a novel system to test MMACHC splice variants, identifying 14 that disrupt splicing and 10 that reduce protein levels, aiding early diagnosis.
Area of Science:
- Genetics
- Molecular Biology
- Biochemistry
Background:
- Methylmalonic aciduria and homocystinuria, cblC type, is the most common disorder of cobalamin (cbl) metabolism, caused by genetic variants in the MMACHC gene.
- Numerous MMACHC splice variants are documented, but experimental validation of their pathogenicity is limited.
Purpose of the Study:
- To experimentally validate the pathogenicity of MMACHC splice variants.
- To establish a novel plasmid system for assessing MMACHC variant effects on splicing and protein expression.
- To improve the early diagnosis of cblC disease.
Main Methods:
- Constructed a plasmid system with the complete MMACHC coding sequence.
- Utilized a minigene assay to evaluate the impact of variants on splicing.
- Quantified protein expression levels for assessed variants.
Main Results:
- Splicing prediction tools identified 26 variants, including missense variants affecting splicing.
- Experimental testing confirmed 14 variants disrupt MMACHC splicing, causing exon skipping, intron retention, and cryptic splicing.
- Ten variants did not affect splicing but significantly reduced protein expression.
Conclusions:
- Elucidated pathogenic mechanisms for several MMACHC variants.
- Validated a novel plasmid system for effective MMACHC variant pathogenicity assessment.
- Highlighted the potential of this laboratory method for early cblC disease diagnosis.
