Commenter seems a bit confused on how both statistics and genetics work (2 images)

Transcription:

Image 1

Doctor in video titled “Is MSA hereditary?”: “As a general rule, in 99.99%, there's no more than one person in a family with MSA.”

Image 2

YouTube commenter
@MegaMusicMuse • 5y ago:
“Then how did my dad and mom both get very similar MSA diseases?”