Mitochondrial protein enriched in neurons that acts as a regulator of mitochondrial respiration (By similarity). Associates with the ATP synthase complex and facilitates ATP synthesis (By similarity). May be a chaperone protein involved in the turnover of the subunits of mitochondrial complex I N-module. It facilitates the degradation of N-module subunits damaged by oxidative stress, and contributes to complex I functional efficiency (PubMed:33465056). Associates with the ATP synthase complex (PubMed:30318146). Interacts with MT-ATP6; interaction is direct (PubMed:30318146). Interacts with ATP5MC2; interaction is direct (PubMed:30318146). Expressed in brain, heart, kidney, liver, lung, spleen, stomach and testis (PubMed:12073013). Highly expressed in the brain (PubMed:30318146). In the neocortex, expressed in most, if not all, glutamatergic excitatory projection neurons (pyramidal) and many interneurons, with the strongest signal noticeably in large pyramidal neurons of layer 3C. Also present in pyramidal neurons of layer 3C PNs of the superior temporal cortex, as well as in pyramidal neurons (Betz cells) of the layer 5B primary motor cortex (at protein level) (PubMed:30318146). DNAJC30 is located in the Williams-Beuren syndrome (WBS) critical region (PubMed:12073013, PubMed:30318146). WBS results from a hemizygous deletion of several genes on chromosome 7q11.23 thought to arise as a consequence of unequal crossing over between highly homologous low-copy repeat sequences flanking the deleted region (PubMed:30318146). WBS is an autosomal dominant disorder characterized by multiple clinical manifestations including neurologic features such as intellectual disability, cardiovascular, urogenital and skeletal features, and distinctive facies (PubMed:30318146). Deletion of DNAJC30 is responsible for mitochondrial dysfunction underlyining certain neurodevelopmental abnormalities observed in WBS (PubMed:30318146). The disease is caused by variants affecting the gene represented in this entry.