In conclusion, the combination of GWAS, homozygosity mapping and WGS identified a 7 bp deletion in GDF7 (c.221_227delGCCGCGC), which is the most likely variant causing feline forebrain commissural malformation, concurrent with ventriculomegaly and interhemispheric cysts in this domestic cat lineage, although the functional analysis has not been achieved to prove the deterministic mechanism. This evidence concerns the gene GDF7 and Ventriculomegaly.