A genetic mutation linked to skin color may put African Americans at high risk for severe vitamin D deficiency - increasing their vulnerability to cancer AND COVID-19 - study suggests Researchers looked at three genes - SLC24A5, SLC45A2 and OCA2 - with strong links to skin color among African Americans Those with a genetic mutation in the gene called SLC24A5 were more likely to have vitamin D levels of 12 nanograms per milliliter (ng/mL) or less Normal levels of the 'sunshine vitamin' range between 20 and 40 ng/mL for a healthy person The team hopes doctors can use the findings to better prescribe vitamin D supplements and help decrease the risk of certain cancers and COVID-19