PRSS35 and pontocerebellar hypoplasia type 6: When examining the 20 most downregulated DEGs in the vestibule (Figure 4D), the top three include Prss35, which is a protein-coding gene located in the mitochondrion and related to serine-type endopeptidase activity and associated with pontocerebellar hypoplasia type 6, Tnn, which is involved in several processes, including generation of neurons and negative regulation of osteoblast differentiation, and Col2a1, which encodes the alpha-1 chain of type II collagen, a fibrillar collagen found in cartilage and the vitreous humor of the eye [45].