Genetic testing is usually carried out using a blood sample, and MLPA is one of more frequently used genetic testing techniques, as it also allows establishing the number of SMN2 gene copies, which has clinical importance.Symptomatically, SMA can be diagnosed with a degree of certainty only in children with the acute form who manifest a progressive illness with paradoxical breathing, bilateral low muscle tone and absent tendon reflexes. Early diagnosis
Early diagnosis of SMA, at the asymptomatic stage of the disease, allows for

Preimplantation testing
Preimplantation genetic diagnosis can be used to screen for SMA-affected embryos during in-vitro fertilisation. Prenatal testing
Prenatal testing for SMA is possible through chorionic villus sampling, cell-free fetal DNA analysis and other methods. Newborn screening
Routine newborn screening for SMA is becoming increasingly commonplace in developed countries, given the availability of causative treatments that are most effective at the asymptomatic stage of the disease. In 2018, newborn screening for SMA was added to the US list of recommended newborn screening tests and as of April 2020 it has been adopted in 39 US states. As of May 2021, SMA newborn screening has been implemented in Taiwan and is in the course of implementation in Australia, Belgium, Canada, France, Germany, Netherlands, Poland, Serbia and Slovenia. Additionally, pilot projects are being conducted in Australia, China, Italy, and Japan. Carrier testing
Those at risk of being carriers of SMN1 deletion, and thus at risk of having offspring affected by SMA, can undergo carrier analysis using a blood or saliva sample.
Its development was discontinued in 2018 in view of competition from nusinersen and underwhelming data from an open-label extension trial.Of clinically studied compounds which did not show efficacy, thyrotropin-releasing hormone (TRH) held some promise in an open-label uncontrolled clinical trial but did not prove effective in a subsequent double-blind placebo-controlled trial. Riluzole, a drug that offers limited clinical benefit in amyotrophic lateral sclerosis, was proposed to be similarly tested in SMA; however, a 2008–2010 trial in SMA types 2 and 3 was stopped early due to the lack of satisfactory results. Other compounds that displayed some neuroprotective effect in in vitro research but never moved on to in vivo studies include β-lactam antibiotics (e.g., ceftriaxone) and follistatin. Muscle restoration
This approach aims to counter the effect of SMA by targeting the muscle tissue instead of neurons. Reldesemtiv (CK-2127107, CK-107) is a skeletal troponin activator developed by Cytokinetics in cooperation with Astellas. The drug aims at increasing muscle reactivity despite lowered neural signalling. The molecule showed some success in phase II clinical trial in adolescent and adults with SMA types 2, 3, and 4. Apitegromab (SRK-015) is monoclonal antibody that blocks the activation of the skeletal muscle protein myostatin, thereby promoting muscle tissue growth. As of 2021, the molecule showed success as an experimental add-on treatment in paediatric and adult patients treated with nusinersen. GYM329 (RO7204239), developed by Hoffman-La Roche, works similarly to apitegromab by blocking myostatin activation. As of 2022, it is undergoing clinical development in non-ambulant children with SMA aged 2–10, combined with risdiplam.