By Meritxell Freixas Arica, Chile, Feb 28 (EFE).- Shortly after he was born, Alison Nateres’ now four-year-old son was diagnosed with a congenital defect that impairs cognitive and motor function. In remarks to Efe, the migrant woman acknowledged that she was aware of the risks of living in Cerro Chuño, an impoverished neighborhood on the …