Persons who do develop symptoms mostly will have symptom onsets 3 to 14 days after exposure to the virus.

Most serological tests would succeed only after a certain period of time past the symptom onset (usually a week).

The average age of symptom onset is 9-11.

All arrived at the hospital within three and a half hours of symptom onset, when tPA works best.

The length of the expanded repeats may affect the age at symptom onset.

In other cases, symptom onset may occur as early as the first year of life.

Although the disorder usually becomes apparent during adulthood, symptom onset may occur at any age.

Patients may become unable to perform daily living activities and most require assistive devices within 5 to 10 years of symptom onset.

Individuals with asplenia often experience symptom onset within a day of exposure.

In severe cases, patients generally begin to deteriorate around three to five days after symptom onset.