AUTHOR=Tian Qi , Shu Li , Zhang Pu , Zeng Ting , Cao Yang , Xi Hui , Peng Ying , Wang Yaqin , Mao Xiao , Wang Hua 

TITLE=MN1 Neurodevelopmental Disease-Atypical Phenotype Due to a Novel Frameshift Variant in the MN1 Gene

JOURNAL=Frontiers in Molecular Neuroscience

VOLUME=14

YEAR=2021

URL=https://www.frontiersin.org/journals/molecular-neuroscience/articles/10.3389/fnmol.2021.789778

DOI=10.3389/fnmol.2021.789778

ISSN=1662-5099

ABSTRACT=<p><bold>Background:</bold><italic>MN1</italic> C-terminal truncation (MCTT) syndrome is caused by variants in the C-terminal region of <italic>MN1</italic>, 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 <italic>MN1</italic> variant in the C-terminal region with mild developmental delay and normal brain magnetic resonance image (MRI).</p><p><bold>Methods:</bold> 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.</p><p><bold>Results:</bold> A <italic>de novo</italic> heterozygous c.3734delT: p.L1245fs variant was detected. HEK239T cells transinfected with the <italic>de novo</italic> variant showed decreased proliferation, enhanced apoptotic rate, and MN1 nuclear aggregation.</p><p><bold>Conclusion:</bold> Our study expended the clinical and genetic spectrum of MCTT which contributes to the genetic counseling of the <italic>MN1</italic> gene.</p>