text: Yo, check it out, let me break it down
  Gonna rap about phenylketonuria, hold your crown
  We gotta expose the causes of delay, my friend
  When PKU patients arrive at the reference center, understand?
  
  Material and methods, let's dive right in
  We evaluated PKU files, it's not a sin
  At the National Institute of Pediatrics, that's the spot
  In Mexico City, where it's hot
  
  Patients divided into groups, listen close
  Group I, early reference, they arrived the most
  First month of life, they were on track
  Group II, late reference, arrived after thirty days, that's a fact
  
  We documented the time and causes of the delay
  Gotta find out why they didn't come right away
  We're here to describe their clinical characteristics
  Digging deep, getting specific
  
  PKU patients, we're on your side
  Gonna uncover the truth, don't hide
  So let's rap about this study, make some noise
  Shining light on PKU, spreading awareness and joys!