When evidence isn’t enough

By the time a human embryo is the size of a blueberry, it has already laid the foundations of its central nervous system. Just four weeks after conception, a flat plate of cells in the embryo has folded over and fused into a tube, the beginnings of its brain and spinal cord. If this neural tube does not close properly, the foetus may develop spina bifida – literally ‘split spine’ – potentially causing a range of disabilities. Such neural tube defects (NTDs) affect hundreds of thousands of births every year, making them one of the most common types of birth defect.