Objective:

To report a case of DEE7 caused by a de novo KCNQ2 large deletion and to explore the associated clinical trajectory and treatment response, specifically focusing on the patient's symptoms and outcomes.

Key Findings:

• The patient achieved complete seizure freedom and modest neurodevelopmental progress following early targeted treatment, highlighting the potential for positive outcomes.
• The identified genetic variants were classified as pathogenic according to ACMG guidelines, underscoring the importance of accurate genetic diagnosis.
• The case highlights the importance of CNV analysis in epilepsy genetic testing, suggesting it may be crucial for understanding patient prognosis.

Interpretation:

Despite the severe genotype associated with a large KCNQ2 deletion, early intervention can lead to significant improvements in seizure control and developmental outcomes, indicating the need for timely treatment.

Limitations:

• Limited number of cases with similar genetic profiles to draw broader conclusions, which may affect the generalizability of the findings.
• Long-term outcomes and treatment responses in patients with large deletions remain under-researched, necessitating further studies.

Conclusion:

This case underscores the potential for positive outcomes with early intervention in patients with severe genotypes and emphasizes the need for comprehensive genetic testing in epilepsy, paving the way for future research.