Background
MN1 C-terminal truncation (MCTT) syndrome is caused by variants in the C-terminal region of MN1, which were first described in 2020. The clinical features of MCTT syndrome includes severe neurodevelopmental and brain abnormalities. We reported on a patient who carried the MN1 variant in the C-terminal region with mild developmental delay and normal brain magnetic resonance image (MRI).
Conclusion
Our study expended the clinical and genetic spectrum of MCTT which contributes to the genetic counseling of the MN1 gene.
Methods
Detailed clinical information was collected in the pedigree. Whole-exome sequencing (WES) accompanied with Sanger sequencing validation were performed. A functional study based on HEK239T cells was performed.
Results
A de novo heterozygous c.3734delT: p.L1245fs variant was detected. HEK239T cells transinfected with the de novo variant showed decreased proliferation, enhanced apoptotic rate, and MN1 nuclear aggregation.