CRISPR-cas9 is one of the most promising new developments in medicine, and in science in general.
For decades, editing genes was a laborious, difficult and expensive process. It could take many months to years to change just one gene, and it would cost hundreds of thousands of dollars, while requiring a state of the art lab. Presently, with CRISPR-cas9 you can change a gene in less than a day at a cost of around 50 dollars.
However, CRISPR-cas9, how revolutionary it may be, is being superseded by even better versions.
In other words, CRISPR 2.0 has arrived.
This is technology like CRISPR-cpf1, which is a smaller, less complex version of the original CRISPR-cas9 protein. Because of its smaller size, CRISPR-cpf1 is easier to insert into viruses, which can carry it into cells. Another advantage is that CRISPR-cpf1 cuts the DNA in a better way (it creates "sticky ends" instead of "blunt ends").
Another example is DNA base editors. The team of professor David Liu at Harvard University developed an adenine base editor (ABE), which is a hybrid of a cas9 protein and a protein that can edit specific pieces of DNA, called adenines.
Base editors are much more accurate than CRISPR-cas9, and this by a long margin. Contrary to CRISPR-cas9, they create much less double-strand breaks and other (off-target) mutations.
The adenine base editor can change an adenine base into a guanine base, which could fix about half of the 32 000 point mutations that cause disease (point mutations account for about two third of the mutations in the human genome associated with disease - about 32000 out of the 50000 disease-causing mutations).
Besides CRISPR-cas9, also CRISPR-cas13 has been developed, which can modify RNA instead of DNA, opening up a whole new world of possibilities to modify the transcriptome, enabling more fine-tuned control of cells compared to editing the genome (DNA).
The toolbox to manipulate the genome, transcriptome, and epigenome is being extended on a continuous basis, paving the way for the manipulation of cells, and life, in ways never seen before.