Two Clans were heavily impacted in some of the edition changes during Vampire’s history.

Assamite Developments

In the Vampire continuity, the Assamites managed to break the Tremere ritual that forced them to abstain from Kindred vitae. If the Storyteller chooses to exercise this option, the Assamites revert to their ancient weakness, which is an addiction to Kindred blood. In this case, when an Assamite so much as tastes Kindred vitae, the player must make a Self-Control or Instincts roll (difficulty equal to the number of blood points ingested +3). If this roll fails, the addiction rises to the fore, and she must make another Self-Control or Instincts roll the next time she comes in contact with Kindred vitae. If this roll fails, the Assamite frenzies, doing whatever she can to partake of more vampiric blood.

In the same continuity, a faction of Assamites has recently made a formal effort to bring the Clan under the auspices of the Camarilla, for both protection and opportunity (and to replace the Gangrel Clan, who has just left the Sect).

Ravnos Developments

At the Storyteller’s option, she may choose to set the chronicle after an event known as the Week of Nightmares. If this is the case, the Ravnos are broken, having lost their Antediluvian in a false start to the End Times, when some of the most powerful supernatural entities in the world collaborated, in fragile detente, to bring down the threat of the ancient blood-god.

This option has no mechanical effect on Ravnos vampires. In the setting however, the Ravnos briefly went mad in the wake of their progenitor’s destruction, and underwent a period of cannibalism and frenzy that left their numbers a paltry fraction of their previous status as they tore each other apart.

Other Developments

There are a number of other developments of note, such as the Gangrel leaving the Camarilla and the Malkavians of the Camarilla having Dominate instead of Dementation as an in-Clan Discipline. Whichever of these elements you decide to use are up to you as Storyteller.