Spinal muscular atrophy type II (SMA-type II)
About
Type SMA-II is caused by a homozygous deletion of the SMN1 gene, retaining 1-2 copies of SMN2. Compared with SMA-I, the progression is slower, but motor function is gradually lost with age. Core dilemmas: ① Scoliosis and thoracic deformities seriously affect respiratory function;② Lifelong treatment is needed to maintain motor function;③Zolgensma is less effective in older children/adults than in infancy.
Features & Symptoms
- 6-18 The onset occurred within a month
- Can sit alone but cannot stand or walk alone
- progressive muscle weakness
- Respiratory function gradually deteriorates
Treatment Options
| Treatment | Description | Stage | Price Range |
|---|---|---|---|
| Onasemnogene abeparvovec（Zolgensma） | One-time gene replacement therapy with AAV9 vector is suitable for patients <21kg. The earlier treatment, the better the retention of motor function. | FDA批准 | $1.5M - $2.1M/次（一次性） |
| Nusinersen（Spinraza） | SMN2 splicing modifier, intrathecal injection, requires lifelong administration. It is suitable for SMA patients of all ages. | FDA批准 | $150K - $750K/年 |
| Risdiplam（Evrysdi） | Oral SMN2 splicing modifier is suitable for patients with SMA 2 months old and above and can be taken at home. | FDA批准 | $100K - $300K/年 |
Prognosis
Most survive into adulthood, but their quality of life is severely limited
Additional Notes
Notes: SMN2 Copy Number Test: SMN2 copy number correlates with disease severity and can help predict treatment response;Zolgensma assessment: patients weighing <21kg have better response, pre-existing AAV9 antibodies and liver function need to be assessed;Risdiplam: oral SMN2 splicing modulator, suitable for patients of all ages, liver function needs to be monitored regularly; Spinal management: scoliosis needs to be evaluated regularly, spinal fusion surgery is necessary; Respiratory and nutritional management: Lung function and nutritional status are assessed regularly, and noninvasive nocturnal ventilation and nutritional support are provided if necessary. Exclusive service commitment: The platform will allocate a dedicated medical team to each patient to assist in dismantling and properly deploying the following precautions throughout the process. When cross-state and cross-border diagnosis and treatment projects or drugs are involved, the platform will make overall arrangements for the entire docking; for disabled and semi-disabled patient groups, the platform will provide rush-free alternative solutions (including remote consultation, door-to-door sampling, direct drug delivery in the cold chain, etc.), to ensure that patients can get the same high-quality diagnosis and treatment resources without having to travel in person.; Study phase: FDA approval. Prognosis: Most can survive into adulthood, but their quality of life is severely limited.
Frequently Asked Questions
What is Spinal muscular atrophy type II (SMA-type II)?
Type SMA-II is caused by a homozygous deletion of the SMN1 gene, retaining 1-2 copies of SMN2. Compared with SMA-I, the progression is slower, but motor function is gradually lost with age. Core dilemmas: ① Scoliosis and thoracic deformities seriously affect respiratory function;② Lifelong treatment is needed to maintain motor function;③Zolgensma is less effective in older children/adults than in infancy.
What are the symptoms of Spinal muscular atrophy type II (SMA-type II)?
6-18 The onset occurred within a month,Can sit alone but cannot stand or walk alone,progressive muscle weakness,Respiratory function gradually deteriorates
How is Spinal muscular atrophy type II (SMA-type II) treated?
Onasemnogene abeparvovec（Zolgensma）: One-time gene replacement therapy with AAV9 vector is suitable for patients <21kg. The earlier treatment, the better the retention of motor function.; Nusinersen（Spinraza）: SMN2 splicing modifier, intrathecal injection, requires lifelong administration. It is suitable for SMA patients of all ages.; Risdiplam（Evrysdi）: Oral SMN2 splicing modifier is suitable for patients with SMA 2 months old and above and can be taken at home.
What is the prognosis for Spinal muscular atrophy type II (SMA-type II)?
Most survive into adulthood, but their quality of life is severely limited