ATP1A1 mutations cause intermediate Charcot-Marie-Tooth disease

Area of Science:

• Genetics
• Neurology
• Molecular Biology

Background:

• Intermediate Charcot-Marie-Tooth (CMT) disease is a group of inherited neuropathies.
• Characterized by progressive distal muscle weakness, atrophy, and sensory loss.
• A significant number of causative genes for intermediate CMT remain unidentified.

Purpose of the Study:

• To identify novel causative genes for intermediate Charcot-Marie-Tooth disease.
• To investigate the functional consequences of identified mutations in the ATP1A1 gene.

Main Methods:

• Whole-exome sequencing was employed to identify genetic mutations in CMT families.
• Functional analyses were conducted to assess the impact of mutations on ATP1A1 protein.
• Messenger RNA and protein expression levels were analyzed, alongside proteasome degradation pathways.

Main Results:

• Two novel missense mutations, c.620C>T (p.S207F) and c.2629G>A (p.G877S), were identified in the ATP1A1 gene in two Chinese CMT families.
• These mutations resulted in a loss of function for the ATP1A1 protein.
• Mutations decreased ATP1A1 protein levels by promoting proteasome degradation, without affecting messenger RNA levels.

Conclusions:

• The ATP1A1 gene is confirmed as a novel causative gene for intermediate Charcot-Marie-Tooth disease.
• The identified mutations in ATP1A1 lead to impaired protein function and expression, contributing to CMT pathogenesis.