Am I entitled to divorce my wife who concealed from me her inheritable disease which caused my son's illness, and is it permissible for me to marry another woman in this situation?

Sickness and health are in the hands of Allah. The transmission of illness from parents to children is not definitive, as the Prophet (peace be upon him) said: "There is no 'Adwa (contagion)." The negation of 'Adwa here refutes the pre-Islamic notion that it transmits by its nature. Indeed, it is Allah who causes illness and grants healing. Therefore, one cannot definitively assert the transmission of illness to their children. A man may marry a second, third, and fourth wife if he is able to bear the expenses and responsibilities of marriage, even if his first wife has no defect. We do not advise divorcing the first wife; rather, one should keep her and treat her kindly.