If the mother was chimeric, she would be chimeric with a 'twin' from the same (grand)mother and father. Therefore her 'twin' chimera would share 50% of her DNA, as any regular sibling.
This would be identifiable on a DNA test as a close relative: she would be genetically equivalent to an aunt rather than a mother.
It's also surprising that they had to test the thyroid when the gametic cell line is the important one (wikipedia suggests they tested her cervix).
If the mother was chimeric, she would be chimeric with a 'twin' from the same (grand)mother and father. Therefore her 'twin' chimera would share 50% of her DNA, as any regular sibling.
This would be identifiable on a DNA test as a close relative: she would be genetically equivalent to an aunt rather than a mother.
It's also surprising that they had to test the thyroid when the gametic cell line is the important one (wikipedia suggests they tested her cervix).