It is possible that the main title of the report Marfan Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
As Jenny points out, being able to lisp the alphabet song at age two has little to do with 'knowing' the alphabet. And, yes, most children learn the letters by sight and sound in kindergarten, although most are capable of learning this information sooner if diligently taught by parents or others.
A few months before he turned 3, he suddenly got it and learned all of his uppercase letters in about two weeks. The point is, 3 is a good age to teach letters, but do NOT stress and pressure your child to learn them. Do lots of fun things to teach and expose him to letters, but donât worry about it.