Heterochromia is a condition where the irises in the eyes of a person or animal are two different colors. This condition can also occur in the color of hair or of the skin, but is most common in the eyes. Heterochromia occurs when a person or animal has too much or too little of the compound melanin in the body. Melanin is a compound found in plants and animals that creates pigment.
Heterochromia can occur from disease, injury, genetic mosaicism, or an inherited genetic trait. Different colored eyes can also occur due to a hemorrhage or foreign object in the eye, glaucoma, or neurofibromatosis. Even mild inflammation in one eye can cause this condition.When it affects the eyes, this condition may also be called heterochromia iridis or heterochromia iridum. The eyes can have either complete heterochromia, meaning each eye is a different color, partial or sectoral heterochromia, meaning that there are two different colors within one iris. Complete heterochromia is the more common variety. The partial or sectoral version usually come from inherited conditions, such as Waardenburg syndrome and Hirschsprung's disease.
Genetics, and signaling pathway
The neural crest (NC) is a unique embryonic structure and contains a multipotent stem cell population that arises during vertebrate embryogenesis. NC stem cells arise from the dorsal neural tube during neurolation in early development and then migrate out from the neural tube and along defined pathways throughout the body, where they contribute to numerous cell types and tissues, including melanocytes, ocular and periocular structures, bone and cartilage cells of the cranial skeleton, sensory neurons, enteric neurons, smooth muscle, endocrine cells, chromaffin cells, and glial cells. Understanding NC development is medically important because defective NC cell development lead to numerous human diseases known as neurocristopathies and heterochromia is an example of one.
The following link is an in-depth explanation of the many transcriptional and signaling pathways for neural crest cells, very interesting! This article shows many combined cell research results of how melanocyte deficiency arises during development. The genes PAX3,SOX10, MITF, SNAI2, EDNRB, EDN3, KIT, and KITL are especially followed and new insights into a central role of MITF in the complex network of interacting genes in melanocyte development is revealed.
FIGURE: A simplified schematic showing the features of key signaling pathways in melanocyte development. Green lines represent three major signaling pathways, WNT, KIT, and EDNRB, which are all connected to Mitf. WNT/
-catenin signaling promotes melanoblast development by regulating MITF transcription. KIT and EDNRB signal pathways are not required for the initial expression of Mitf in melanocyte development, but both pathways induce the phosphorylation of MITF in mature melanocytes.
-catenin signaling promotes melanoblast development by regulating MITF transcription. KIT and EDNRB signal pathways are not required for the initial expression of Mitf in melanocyte development, but both pathways induce the phosphorylation of MITF in mature melanocytes. 
No comments:
Post a Comment