Normal development of our bodies relies on blood vessels forming correctly and in the right places. When this process goes awry it can cause vascular anomalies ranging from small birthmarks to severely malfunctioning organs. People with the vascular disorder hereditary haemorrhagic telangiectasia (HHT) may be born with malformations in organs such as their lungs, liver or brain. HHT can be caused by mutations in various genes including one called BMP9. When functioning normally it tells cells to turn genes on or off, controlling when they grow or migrate. It does the same in zebrafish: the upper picture shows how the vein usually grows. But in the lower picture BMP9 has been switched off. Epithelial cells lining the vein (shown in green) indicate its distorted shape which has misdirected the flow of blood (purple). Finding out about molecular switches like BMP9 will help identify and treat diseases like HHT.
Written by Esther Redhouse White
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