Infants and young children with unrepaired tetralogy of Fallot are often blue (cyanotic).
患有法洛四联症的婴幼儿经常表现为颜面、口唇青紫（发绀）。
英语百科
Tetralogy
（重定向自Tetralogies）
A tetralogy (from Greek τετρα- tetra-, "four" and -λογία -logia, "discourse") is a compound work that is made up of four distinct works. The name comes from the Attic theater, in which a tetralogy was a group of three tragedies followed by a satyr play, all by one author, to be played in one sitting at the Dionysia as part of a competition.