Inclusion Criteria:

All Participants:

- Not eligible for treatment with currently approved treatments for SMA, or cannot
continue treatment with currently approved medications as documented by the treating
physician, or in the treating physician's judgment, the participant is at risk of
lack/loss of treatment efficacy of the current therapy.

- The participant does not qualify for and has no access to SMA treatment in the
context of an ongoing clinical trial.

- Adequately recovered from any acute illness at the time of screening, and considered
clinically well enough to participate, in the opinion of the treating physician.

- Participants with retinopathy of prematurity should have evidence of stable disease.

Type 1 SMA Participants:

- Confirmed diagnosis of 5q-autosomal recessive SMA.

Type 2 SMA Participants:

- Confirmed diagnosis of 5q-autosomal recessive SMA.

- Negative blood pregnancy test at screening (all women of childbearing potential,
including those who have had a tubal ligation), and agreement to comply with
measures to prevent pregnancy and restrictions on egg and sperm donation.

- Males with female partners of reproductive potential must agree to use highly
effective contraception during therapy, and for at least 4 months after treatment
discontinuation.

Exclusion Criteria:

- Inability to meet program requirements.

- Concomitant or previous participation in any investigational drug or device study
within 90 days prior to screening or 5 half-lives, whichever is longer.

- Administration of other SMN-2 targeting therapy within 120 days of starting
risdiplam therapy.

- Administration of SMA gene therapy within the last 3 months (12 weeks) of receiving
risdiplam therapy.

- Any serious medical condition, treatment, or abnormality in clinical laboratory
tests that, in the treating physician's judgment, precludes the participant's safe
participation in the program.

- Ascertained or presumptive hypersensitivity (e.g., anaphylactic reaction) to
risdiplam or to the constituents of its formulation.

- Suspicion of illicit drug or alcohol abuse, in the treating physician's judgment.

- Any prior use of an inhibitor or inducer of flavin-containing monooxygenases 1
(FMO1) or flavin-containing monooxygenases 3 (FMO3) taken within 2 weeks (or within
5 times the elimination half-life, whichever is longer) prior to dosing.