Apparently this was a case of rotten luck.
https://archive.ph/zRGFB

Bella went viral on social media after showcasing her vibrant personality as her parents Kyla and Lyle documented her life-threatening health challenges with the rare bowel illness Hirschsprung’s disease and severe combined immunodeficiency (SCID), among other health problems [dwarfism likely the biggest contributor to the appearance].
Bella's death comes just days after the 10-year-old was placed in a medically induced coma after suffering complications from a viral infection in her lungs, Kyla told PEOPLE on July 11.

Both parents look pretty normal (though I admittedly haven't learned to recognize telltale head/face features).