Is ttn genetic, is there a gene I should know about?

No! If you mean transient tachypnea of the newborn it is not genetic.
No and no. By definition, ttn or transient tachypnea of the newborn, is a temporary condition. It usually lasts less than 6 hours, and is more common after a c-section because the newborn has not cleared the amniotix fluid from their lungs.