Zha J, Chen Y, Cao F, Xu Y, Yang Z, Wen S, Liang M, Wu H, Zhong J. Homozygous variant of
MLC1 results in megalencephalic leukoencephalopathy with subcortical cysts.
Mol Genet Genomic Med 2024;
12:e2394. [PMID:
38337154 PMCID:
PMC10858299 DOI:
10.1002/mgg3.2394]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 01/18/2024] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare, inherited disorder that causes epilepsy, intellectual disorders, and early onset macrocephaly. MLC1 has been identified as a main pathogenic gene.
METHODS
Clinical data such as magnetic resonance imaging (MRI), routine blood tests, and physical examinations were collected from proband. Trio whole-exome sequencing (WES) of the family was performed, and all variants with a minor allele frequency (<0.01) in the exon and canonical splicing sites were selected for further pathogenic evaluation. Candidate variants were validated using Sanger sequencing.
RESULTS
Here, we report a new homozygous variant identified in two children from the same family in the MLC1 gene [NM_015166.4: c.838_843delinsATTTTA, (p.Ser280_Phe281delinsIleLeu)]. This variant is classified as variant of uncertain significance (VUS) according to the ACMG guidelines. Further experiments demonstrate that the newly identified variant causes a decrease of MLC1 protein levels when expressed in a heterologous expression system.
CONCLUSION
Our case expands on this genetic variation and provides new evidence for the clinical diagnosis of MLC1-related MLC.
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