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.
I'm surprised that you think a 3 year old is suppose to recognize all letters and numbers. My daughter will be 4 in March and knows a few numbers and a few letters. She's been going to daycare since she was 6 months. They have homework everyday where they trace letters and numbers.