[Metabolism of monocarbons and trisomy 21: sensitivity to methotrexate]

A diminution of the mitotic index, proportionnal to the square of the dose of methotrexate, was observed in lymphocyte cultures. Six trisomy 21 patients were twice as sensitive as six controls. This highly significant result confirms the hypothesis of a disturbance of monocarbons' metabolism in trisomy 21.