A study of newborn screening in New York City was conducted between October 2018, when the state added SMA to its panel of diseases routinely screened at birth, and September 2021. During those three years:
- 34 newborns were diagnosed out of 650,000 tested (about a 1-in-19,000 frequency) at 9 New York State centers, including 1 newborn with 1 copy of SMN2, 18 with 2 copies of SMN2, 11 with 3 copies of SMN2, and 4 with >4 copies of SMN2.
- All infants were confirmed by genetic testing, so there were no false positives,
Of the thirty-two (94%) who received treatment:
- some took a single treatment: 71% Zolgensma®, 3% Spinraza® and 3% Evrysdi®,
- others received a combination of treatments: 17% treated with Spinraza® before being infused with Zolgensma® (they then stopped treatment with Spinraza®) and 6% treated with Zolgensma® who then started treatment with Evrysdi®,
- the 11 infants with 3 copies of the SMN2 gene treated before the onset of symptoms remained asymptomatic: those who were more than one year old at the end of the study could walk independently
- the 18 infants with 2 copies showed more variable results depending on when the treatment was initiated, if the symptoms were already present or not…