The teen suffered from progeria, or Hutchinson-Gilford syndrome, a very rare genetic disorder that results in symptoms of premature ageing.

Rania became famous online thanks to the humorous videos she created with French YouTuber GameMixTreize.

It was he who announced her death online Thursday night, prompting many retweets and tributes.

The young woman was mostly known for her maintaining her sense of humour and optimism despite suffering from the rare syndrome called progeria.

A very rare disease

Hutchinson-Gilford syndrome is little known and rarely spoken about, as it currently only affects 100 to 200 people in the world.

And while the disorder may bring the film “The Curious Case of Benjamin Button” starring Brad Pitt to mind, in reality people who suffer from this disease don’t become younger with time.

The disease is fatal in all cases, and sufferers live to an average age of 13-14 years.

Technically, “progeria is caused by mutations in the LMNA gene, but almost always results from a new mutation rather than being inherited from a parent,” explains the US Rare Diseases Information Centre.

The mutation in the LMNA gene codes for a protein that provides the molecular scaffolding of cell nuclei.

The defective protein entails nuclear instability from cell division and early death of every body cell.

The US Rare Diseases Information Center notes that this syndrome is “characterized by dramatic, rapid aging beginning in childhood” with symptoms typically seen in much older people such as baldness, aged-looking skin and cardiovascular affections. Children and teens who suffer from this disease tend to remain very short and usually weigh around 20 kilos.

There is no known progeria treatment, however, scientists are studying certain mechanisms that could prolong patients’ lives, albeit only by a couple of years.