Congenital suffering is not always a simple punishment for a person's or parents' personal sin.

John 9:1–3

¹And as Jesus passed by, he saw a man which was blind from his birth.

²And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind?

³Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.