NAJC30 is a member of the DNAJ molecular chaperone homology domain-containing protein family. DNAJC30 gene is deleted in williams syndrome, a multisystem developmental disorder caused by the deletion of contiguous genes at 7q11.23. DNAJC30 is expressed in brain, heart, kidney, liver, lung, spleen, stomach and testis. It contains 1 J domain. DNAJC30 is located in the Williams-Beuren syndrome (WBS) critical region. 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.