18 people, who have been divided into 2 groups based on the semiquantitative expression of a protein (low vs high).

Group 1 (low protein levels) has 6 people, Group 2 (high protein levels) has 12 people. In Group 1, 5 of the 6 people developed a specific disease, whereas only 2 of 12 in Group 2 developed this disease.

I want to determine if there is a statistically significant correlation between low protein levels and the development of this specific disease.

If someone could point me towards the tests I should use, it would be great.