NODAL and ciliopathy: The molecular defects that underlie laterality defects alone, without other features of ciliopathies are more complex and include disruption of ciliary proteins (CFAP53 [8] and PKD1L1 [9]) leading to dysmotility of the nodal cilia and proteins not directly associated with cilia (CFC1 [10], ACVR2B [11], NODAL [12], MMP21 [13] and ZIC3 [11]) acting through Nodal and Notch1 signalling pathways.