Reduced ceramide synthase 2 activity causes progressive myoclonic epilepsy

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• Sphingolipids (SLs) are vital for brain function, and their altered levels are implicated in neurodegenerative disorders like epilepsy.
• However, direct genetic links between SL metabolism and epilepsy remain scarce.

Purpose of the Study:

• To investigate the role of ceramide synthase 2 (CERS2) in progressive myoclonic epilepsy (PME).
• To identify genetic variations in CERS2 and their functional consequences on SL metabolism and brain cell function.

Main Methods:

• Quantitative real-time PCR, Western blotting, and enzymatic assays to measure CERS2 mRNA, protein, and activity levels in patient fibroblasts.
• Mass spectrometry and fluorescence microscopy to analyze lipid composition and plasma membrane alterations.

Main Results:

• A novel heterozygous deletion encompassing the CERS2 gene was identified in a PME patient.
• Fibroblasts from the patient showed approximately 50% reduction in CERS2 mRNA, protein, and activity.
• This resulted in decreased levels of ceramides and SLs with very long-chain fatty acids (C24:0, C26:0) and altered membrane function.

Conclusions:

• Reduced CERS2 levels and subsequent diminished very long-chain fatty acid-containing ceramides and SLs are proposed as a cause for PME.
• This study highlights a potential genetic and metabolic basis for PME, linking CERS2 dysfunction to the disease.