Rock Disease

The Rock Disease is an unnamed affliction that particular characters in Part VIII: JoJolion suffer from. It has been confirmed to be a hereditary illness passed down through the Higashikata family and by extension the SBR Joestar family.

Physical affects
The bodies of those who suffer from this disease are known to begin to harden like rock beginning at the age of 11. As the symptoms progress the victim loses more and more of their functions and memories until they eventually die.

There is a possibility that the nature of the rock disease has ties to the mysterious rock people who have begun to appear all over Morioh.

History
The earliest chronological example of the disease appears in the Shakedown Road arc during a flashback narrated by one of the inhabitants sitting at a bench. He recalls the rumors of Johnny Joestar travelling to America to recover the corpse of a saint in order to cure his wife of her affliction using its ability to 'remove' unwanted things and push them elsewhere.

Although he succeeds in doing so the sickness is pushed instead onto his young son, and so in a desperate move he utilizes the spin to transfer the disease to himself before being flattened by a stone under the affects of the newly developed Les Feuilles.

Current story
It is mentioned that the firstborn of every generation in the Higashikata family suffers from this disease, and the only way they have survived it is through another member of the family utilizing the equivalent exchange properties of the lone pine to take their place.

It is Tsurugi's fear for his inevitable contraction of this condition that motivates him to succumb to Yotsuyu's manipulation, exploiting the young boy into helping him set a trap for the protagonist. It is first hinted then and later expanded upon that the Rokakaka also seems to have the ability to 'cure' the Rock sickness, although it's full affects have not been observed as the only known case was the dog Iwasuke.

Sufferers

 * Rina Higashikata (cured by the corpse)
 * George Joestar II (replaced by Johnny)
 * Johnny Joestar
 * Norisuke Higashikata IV (replaced by his mother)
 * Mother of Norisuke Higashikata IV
 * Holy Joestar-Kira (mysteriously living)
 * Jobin Higashikata