DEE market to surge almost 12% annually on gene therapy advances

Patient pool rises to 326,000 by 2036 across 7MM as diagnosis rates increase.

The developmental and epileptic encephalopathies (DEE) market is projected to have a compound annual growth rate of 11.7% from 2026 to 2036, driven by rising diagnosis rates and the development of gene therapies and antisense oligonucleotide-based approaches.

A DelveInsight report valued the market at $2.2b across seven major markets—the US, Germany, France, Italy, Spain, the UK, and Japan—in 2025, with the US accounting for around 59% of total market size.

The diagnosed prevalent population is expected to rise from approximately 288,000 in 2025 to 326,000 by 2036, supported by wider genetic testing and earlier identification of rare paediatric epileptic disorders.

Growth is increasingly driven by a shift away from symptomatic seizure control toward disease-modifying therapies targeting underlying genetic mechanisms.

The report highlighted multiple late-stage pipeline therapies, alongside approved treatments, including approaches based on antisense oligonucleotides, gene therapy, and small molecules targeting specific mutations.

“Despite recent progress, the DEE market remains largely underserved, as many genetically defined DEE subtypes still lack approved targeted treatment options, leaving considerable unmet clinical need,” the report said.