Turtles are excellent models for the study of developmental instability because anomalies are easily detected in the form of malformations, additions, or reductions in the number of scutes or scales.
Most reptiles, and particularly turtles, are excellent models for the study of developmental instability because anomalies are easily detected in the form of malformations, additions, or reductions in the number of scutes or scales (Figure 1).
According to the Palmini classification, the observation of 'excess' heterotrophic neurons in layer I and the white matter are classified as mild forms of Malformation of Cortical Development (mMCD) type I and II respectively [ 1].
Assessment errors introduced during the scoring of the malformations, leading to the detection of false positives, are also not a likely explanation, because we disregarded the milder forms of malformations that may be difficult to diagnose.
Endo et al. found a total of 12 reported cases and added the case of a Japanese girl with a unique form of this malformation complex.
The most severe form of anorectal malformation in females – cloaca – is characterized by failed septation of the rectum, vagina and urethra, resulting in a common channel and a single orifice.
We then used these animals to perform a broad comparison with patients with mild-to-severe forms of anorectal malformations including cloaca malformation.
Congenital brain malformations outside the cerebellum can, in turn, cause herniation of cerebellar tissue, as seen in some forms of Arnold Chiari malformation.
The observation of PMG in association with other and better understood forms of brain malformation, such as cobblestone cortex, suggests mechanistic pathways for some forms of PMG.
Here we compared human and mouse cloaca development and retrospectively identified that early mis-patterning of the embryonic cloaca might underlie the most severe forms of anorectal malformation in humans.
