Читать книгу Pathology of Genetically Engineered and Other Mutant Mice - Группа авторов - Страница 99

Laterality defects can only be identified on gross exam, and prosectors need to be alert because these phenotypes are surprisingly easy to overlook during necropsies, especially since fewer than 50% of the homozygous mice will display any situs phenotype in most affected lines. One critical role for cilia is the specification of the left–right (LR) body axis during development. Motile cilia alongside the embryonic node, a cup‐shaped structure on the ventral surface of the developing embryo, generate a flow that is detected by sensory cilia within the node [34], with both types of cilia required for normal left–right axis patterning [27]. Defects in motile cilia are likely when the laterality defects are accompanied by rhinosinusitis, male infertility, or hydrocephalus, whereas the absence of these lesions is suggestive of a sensory ciliopathy [27]. The term situs solitus is used to describe the normal left–right (LR) asymmetry in the positioning of internal organs [35, 36], while a mirror image reversal of organ positioning is called situs inversus [37, 38]. The terms situs ambiguus or heterotaxy are used to describe other variations in organ placement due to abnormal left–right patterning during embryonic development.