4e Dragonborn vs. the Dragonborn of Bahamut
Different Ability score modifiers (Str vs. Con), totally different aging categories (almost human vs. 200 years per age category), different set of racial features (Dragonborn Fury, Draconic Heritage, and Dragon Breath vs. Immunity to Frightful Presence, AC bonus vs. Dragons, and Draconic Aspect: Heart (Dragonbreath like the above), Mind (darkvision and keen senses), or Wings (Flight and Gliding)).
So they are almost but not quite totally unlike each other. However, if you choose Heart for the Draconic Aspect, turn sideways, squint, and bounce a little you could see the similarity. Beyond that the only thing they have in common is that they are both dragonthemed races.