Any lethal congenital contracture syndrome in which the cause of the disease is a mutation in the ADGRG6 gene. The disease is lethal congenital contracture syndrome 9 (MONDO_0014670, a Monarch Disease Ontology entry). Also known as: ADGRG6 lethal congenital contracture syndrome, lethal congenital contracture syndrome caused by mutation in ADGRG6, lethal congenital contracture syndrome type 9.