Comment on “Spinal Muscular Atrophy Carrier Screening: Assessment of Provider Knowledge and Clinical Practice”

Spinal muscular atrophy (SMA) is the most common neurodegenerative genetic disorder. It is associated with insufficient survival motor neuron (SMN) protein, which causes progressive motor neuron degeneration, skeletal and respiratory muscle weakness, and early death in the most severe untreated cases. Earlier treatment is associated with improved outcomes, making carrier screening an important part of prenatal care. Noncarriers of SMA typically have 2 functional copies of the SMN1 gene, while carriers usually have only one. Some carriers, called “2 + 0” carriers, can go undetected by standard testing because they have 2 SMN1 copies on one chromosome and none on the other. This genotype is more common among patients with sub-Saharan African ancestry. Linked variants can help identify patients at increased risk for this genotype, but do not confirm carrier status on their own. This study aimed to assess provider knowledge, practice patterns, and comfort with SMA carrier screening and result interpretation at a large academic OBGYN department.

This cross-sectional study surveyed prenatal care providers at the University of Pennsylvania Health System between 2022 and 2023. Eligible participants included prenatal providers across 5 outpatient clinics, including OB generalists, MFMs, residents, fellows, nurse midwives, and advanced practice providers. Participants were invited to complete an anonymous 20-item online survey assessing SMA carrier screening knowledge, result interpretation, and clinical practice patterns. The survey was developed using ACMG and ACOG guidance with input from maternal–fetal medicine, genetics and genetic counseling experts. Knowledge questions were scored as correct or incorrect, and practice-pattern responses were reported descriptively. Analyses evaluated the relationship between provider role, years of experience, knowledge, and comfort with counseling.

Of 150 invited providers, 112 began the survey and 97 completed it. Overall knowledge was limited, with a mean score of 3.8 out of 8, 20.6% scoring ≥75%, and 51.6% scoring ≥50%. MFM providers had significantly higher scores than non-MFM providers, while years in practice did not affect performance. Most providers offered screening at the first prenatal visit, but only 23.9% reported complete comfort discussing screening, and 20.7% reported complete comfort discussing results. Providers were least comfortable with symptoms and prognosis, result interpretation, inheritance pattern, and linked-variant results. Providers with higher knowledge scores were more likely to report greater comfort discussing the results with patients.

These findings suggest that provider education may be an important barrier to effective SMA carrier screening. This aligns with previous research on the uptake and understanding of CF screening, which revealed similarly low confidence among providers. Interpreting SMA screening results is even more complex than that of CF screening because of variable phenotypes and potential for linked variant results, which may explain why provider adoption remains low. Study strengths include a standardized survey with response rates comparable to other survey-based studies, while limitations include the single-site design, possible nonresponse and self-selection bias, and limited generalizability to private or rural practice settings. Overall, the authors conclude that targeted educational efforts are needed to improve provider understanding of screening, result interpretation, and follow-up counseling.

(Summarized from Riegel M, Bender W, Critchlow E, et al. Spinal muscular atrophy carrier screening: assessment of provider knowledge and clinical practice. Prenat Diagn . 2026;46:229–235. doi:10.1002/pd.70023).