Diagnostic yield and copy number variants findings in 219 adult patients with developmental and epileptic encephalopathy.

Detection of causative CNVs (8.2%) by chromosomal microarray in undiagnosed adults

In adults, trio exome is often not feasible and CNV-calling tools lack accuracy. The authors assess chromosomal microarray (array-CGH/SNP) in 219 adults with undiagnosed developmental and epileptic encephalopathy (DEE). Causative CNVs are identified in 8.2% (18/219): 14 deletions (mean ~2.96 Mb) and 4 duplications/triplications (~3.63 Mb). Thirteen correspond to known deletion/microduplication syndromes and four to deletions of haploinsufficient epilepsy-associated genes.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

Confirms the value of CNVs in the aetiological work-up of adult DEE, a population where trio testing is rarely feasible. A practical argument for maintaining robust CNV analysis — ideally integrated into WES/WGS — rather than relying on short-variant sequencing alone.

Analysis by Dr Thibaut Benquey