Experience with Newborn screening for SMA at a tertiary centre in California

Topic:

Clinical Management

Poster Number: Virtual

Author(s):

Amanda Yaworski, MD, Stanford Health Care, Tina Duong, PhD, Stanford University, Jenna Klotz, MD, Stanford University, Sally Dunaway Young, PT, DPT, Stanford University, Karolina Watson, NP, Stanford, Jessica Guzman, Stanford University, Miranda Clements, SLP, Stanford University, Whitney Tang, Stanford University, Jennifer Low, Stanford University, Richard Gee, PT, Stanford University, Jacinda Sampson, MD, PhD, Stanford University, John Day, MD, PhD, Stanford University, Carolina Tesi Rocha, MD, Stanford University

Objectives: To assess the impact of newborn screening on SMA patients’ outcome.
Methods: We performed chart review of all patients identified via newborn screening between June 2020 and September 2022 at our institution and collected clinical data including motor, bulbar function and respiratory function.
Results: 6 children were identified; 4/6 patients identified prenatally. 5 patients had 2 copies of SMN2 while 1 had 3 copies. All patients were treated with onasemnogene Abeparvovec between 1-4 weeks of life, and 2 patients received oral risdiplam as a bridge to gene therapy. CHOP-intend scores at birth ranged from 31-45 with a mean of 40. All patients showed improvement in scores over time with a mean increase of 13 points (9-18) approximately 3 months after treatment. This is slightly lower than what has been reported in clinical trials with a mean of 16.7 points after 3 months1. Our oldest patient was 2.5 years at most recent assessment. Of patients who are >1 year past treatment, 2 are walking with support (10 & 22 months) and one is able to roll (13 months) but still unable to sit independently. Our patients show slightly less functional improvement compared to that reported in literature2. One patient was treated with combination therapy due to suboptimal response, receiving nusinersen 7 months after gene therapy (8 months of life). 4/6 patients showed swallowing dysfunction within the first month of life without any functional decline on standard testing.
Conclusion: We confirmed that identifying SMA patients prenatally or via newborn screening results in earlier identification and in turn improved outcomes. Motor scores in some cases were lower than what was reported in clinical trials in presymtomatic population. Swallowing dysfunction appears to be one of the earliest signs of disease and routine screening should be completed.