Functional analyses of mutations in HEPACAM causing megalencephalic leukoencephalopathy
Tanit Arnedo1, Tania López-Hernández, Elena Jeworutzki
1Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain; U-750, Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain.
Abstract:
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy characterized by white matter edema. Autosomal-recessive mutations in MLC1 cause MLC type 1, and autosomal-recessive or dominant mutations in HEPACAM (also called GLIALCAM) cause MLC type 2A and type 2B, respectively. The role of MLC1 and HEPACAM is unknown, although they have been related with the processes of cell-volume regulation and potassium siphoning by astrocytes. Previous studies with some of the mutations identified in HEPACAM showed that most of them are associated with a trafficking defect. Here, we analyzed biochemically and functionally most mutations identified up-to-date in HEPACAM. Our results allow classifying the effect of mutations in different subtypes and we indicate different cellular mechanisms that lead to MLC pathogenesis.
Insights
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy. This study analyzes HEPACAM mutations, revealing distinct cellular mechanisms underlying MLC pathogenesis.
Area of Science:
- Neuroscience
- Genetics
- Cell Biology
Background:
- Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy.
- MLC is characterized by white matter edema.
- Mutations in MLC1 and HEPACAM (GLIALCAM) cause different types of MLC, with their exact roles unclear but linked to astrocyte functions.
Purpose of the Study:
- To biochemically and functionally analyze known HEPACAM mutations.
- To classify the effects of these mutations.
- To elucidate cellular mechanisms contributing to MLC pathogenesis.
Main Methods:
- Biochemical analysis of HEPACAM mutations.
- Functional assessment of HEPACAM mutations.
- Classification of mutation effects and cellular mechanisms.
Main Results:
- Most identified HEPACAM mutations are associated with protein trafficking defects.
- The study successfully classified the effects of numerous HEPACAM mutations.
- Different subtypes of MLC pathogenesis linked to distinct cellular mechanisms were identified.
Conclusions:
- HEPACAM mutations lead to MLC through various cellular mechanisms.
- Understanding these mechanisms aids in classifying MLC subtypes.
- This research provides insights into the pathogenesis of leukodystrophies.
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