A few years ago, a young Canadian man with cystinosis underwent an experimental stem cell therapy. The treatment produced surprising side effects, including a striking genetic shift in his hair color—a outcome researchers now view as a potential sign of success.
Serendipity often drives breakthroughs, like the accidental discovery of self-repairing polymers during smartphone screen research in 2017. In medicine, similar unexpected findings emerge regularly.
As detailed in a recent The Atlantic article, 20-year-old Jordan Janz was diagnosed with cystinosis in 2019. This rare genetic disorder causes an excess of cystine—an amino acid—to accumulate in cells of the kidneys, eyes, brain, liver, pancreas, and muscles. Without treatment, life expectancy averages under 30 years.
Janz received an experimental therapy using modified stem cells, which initially caused side effects like painful mouth sores that hindered eating and the loss of his pale blond hair.
As Janz recovered over the following months, his hair regrew—but dramatically darker, nearly black. It has since lightened to dark blond. Researchers at the University of California, San Diego, who developed the therapy, suggest this darkening indicates the treatment is effectively addressing the underlying genetic issues.
Janz isn't alone: four of five Caucasian patients in the trial experienced similar hair darkening, while the fifth saw changes in regrowth patterns. Cystinosis patients often appear paler than relatives.
Prior studies link the cystinosis gene to melanin production, the pigment determining skin and hair color. This effect appears specific to Caucasians, with no clear tie to disease severity in other groups.
