In this case report we present a novel homozygous in-frame ARV1-deletion (c.554_556delTAT, p.L185del) in a 21-year old Caucasian man with developmental delay, intellectual disability, seizures, walking and speech impairments, as well as with a dilated cardiomyopathy (DCM), which has not yet been firmly related to the ARV1-associated phenotype. Here, ARV1 is linked to Global developmental delay.