No association between SCN9A and monogenic human epilepsy disorders

Area of Science:

• Human Genetics
• Neurology
• Epilepsy Research

Background:

• Epilepsy gene panel testing is crucial for diagnosing seizure disorders and guiding treatment.
• The SCN9A gene, specifically the c.1921A>T p.(Asn641Tyr) variant, was previously considered a cause of certain epilepsy phenotypes.
• This led to the inclusion of SCN9A in epilepsy gene testing panels.

Purpose of the Study:

• To investigate the association of the SCN9A c.1921A>T p.(Asn641Tyr) variant with epilepsy.
• To re-evaluate the diagnostic utility of SCN9A in epilepsy gene panels.

Main Methods:

• Analysis of genetic data from the Amish community.
• Examination of findings from the UK Biobank.
• Phenotypic correlation of SCN9A variant carriers.

Main Results:

• The SCN9A c.1921A>T p.(Asn641Tyr) variant was found at high frequency in the Amish population.
• No epilepsy or related seizure phenotypes were observed in these high-frequency carriers.
• UK Biobank data corroborated the lack of association between SCN9A and epilepsy.

Conclusions:

• The SCN9A c.1921A>T p.(Asn641Tyr) variant is not associated with epilepsy.
• This finding has significant implications for the clinical diagnosis of epilepsy.
• SCN9A should be reconsidered for inclusion in epilepsy gene testing panels.