Aslaam-o-Alaicum,
I am now 40 years old, when I was about only 3 to 4 years old, as my mother told me, one person having white beard was selling Quran and Siparas on bicycle in the streets of our area. One time my mother stopped him to buy a Sipara and as I was a child, I stand up next to my mother. 
The man asked to my mother that who is this child? My mother said this is my son. He said that he has “Invisible Alif” sign on his forehead. My mother was thinking that he might saying this because he want to get some money, but he did not asked for any money and not even the money for Sipara my mother bought from him.
As I said that now I am 40 years old, but these words are still in my mind and never forgot, but I never understand that is this real prediction? If it is, then what could be the meaning of it?
 
I will appreciate your response about it. Thanks very much.