The Same White Patch
Although it looks like this woman and her baby are cosplaying Cruella de Vil, the white patches in their hair are actually because of a genetic mutation. They have poliosis circumscripta, which is not a spell from Harry Potter, but it causes a prominent white streak in the hair.
Source: fatima.theo.gomes
The mother passed down this unique genetic condition to her son, and they are rocking the white patch of hair. Poliosis circumscripta, traditionally known as “white forelock,” occurs because of decreased or absent melanin in the hair follicles. It can occur in other hairy areas, like the eyebrows or eyelashes.