Amutation occurs in a sex cells of a full-grown zebra the mutation to fix the genes responsible for producing blood proteins what will most likely happen to the zebra

The zebra's descendence (offsprings) will not be able to produce blood proteins (hypoproteinemia)

It touches the offspring and not the zebra itself because only the sex cells which gives spermatozoids or ovules) are touched.
The main symptom of hypoproteinemia is swelling of the legs, face and other parts of the body due to fluid accumulation loss of muscle mass.

The higher you go up the less oxygen there is