The workflow of the Osaka spinal muscular atrophy (SMA) newborn screening (NBS) program is useful for babies with the disease, a new study published in Brain and Development confirmed. 

Currently, only around one-fifth of newborn babies are screened for SMA in the country, which the authors of the present study believe is insufficient.

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To establish an optional NBS program for the disease in Osaka, the team led by Yasuhiro Suzuki, PhD, of the Department of Pediatric Neurology at Osaka Women’s and Children’s Hospital in Izumi, Japan used a polymerase chain reaction (PCR)-based assay to screen for SMA in 22,951 newborns between February 1, 2021 and September 30, 2021.

The team used dried blood spot samples that were collected for the NBS program, which was optional, for severe combined immunodeficiency, which accounts for about half of the newborns in Osaka. 

The results showed that all babies screened during this period of time were negative for deletions in the SMN1 gene, the leading cause of SMA. 

Based on these results, the researchers developed an SMA-NBS program and included it in the optional NBS programs offered in Osaka from October 1, 2021. 

Since then, 1 asymptomatic baby with SMA was identified, and treatment was started immediately.

There are currently 2 disease-modifying therapies approved in Japan for the treatment of patients diagnosed with SMA using genetic testing before symptom onset. Research has shown that treating patients with SMA before symptoms of the disease appear leads to significantly better motor development than that seen in patients treated after the onset of symptoms.

“Optional NBS programs are unfair to parents,” the researchers wrote. “We believe that all NBS programs should be fair to all parents and hope that describing the results of our optional SMA-NBS program will lead to the development of mandatory SMA-NBS programs in Japan.”


Kimizu T, Ida S, Oki K, et al. Newborn screening for spinal muscular atrophy in Osaka -challenges in a Japanese pilot study. Brain Dev. Published online March 25, 2023. doi:10.1016/j.braindev.2023.03.004