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.
According to the U.S. Department of Education, here are the language milestones your child should reach at each age: CHILDREN AGES 0-3: Imitate some of the sounds and rhythms adults use when they speak. Begin to associate frequent words with their meanings. Recognize some books by their covers.