Therefore, human laterality defects can be caused by mutations in genes encoding proteins important for the integrity of the ciliary motility apparatus, resulting in impaired ciliary motility and subsequent impaired or disturbed leftward fluid flow within the embryonic node. In addition, laterality defects can occur in non-motility-related ciliopathies, for example due to mutations in Inversin15 (MIM: 243305), PKD1L116, 17 (MIM: 609721), PKD218, 19 (MIM: 607074), or NPHP320 (MIM: 608002), where non-motile mechano-sensory monocilia at the margin of the embryonic node are thought to be defective. In addition, signals at the node are also further processed without the involvement of cilia. As a consequence, laterality defects are also observed due to defects in genes encoding non-ciliary proteins, e.g., due to mutations in ZIC321 (MIM: 300265), ACVR2B22 (MIM: 602730), NODAL23 (MIM: 601265), GDF124 (MIM: 602880), or MMP2125 (MIM: 608416).