Medical Research Council - London Institute of Medical Sciences

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World Down Syndrome Day Inside Down
21 March 2013

Inside Down

Twenty-three pairs of chromosomes locked within our cells hold the key to the development of the human body. Today, on World Down Syndrome Day, it’s pair number 21 that draws our attention. A developmental defect called trisomy 21 means each human cell ends up with not two, but three, copies of chromosome 21. This results in Down syndrome; a condition characterised by a delay in mental development, short stature and a distinct set of facial characteristics. Heart and immune system defects are also often found and may be explained by differences at the level of cells – specifically, endothelial progenitor cells (EPCs) that circulate in the blood. Scientists found fewer EPCs in individuals with Down Syndrome, and those present were more sensitive to stress and infection. Electron microscopy shows abnormalities in their appearance too – the EPCs (pictured) are larger and have more vacuoles (white spaces) than normal cells.

Written by Lux Fatimathas

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