Newborn Screening for Spinal Muscular Atrophy in New York State: Clinical Outcomes From the First 3 Years.

Abstract

BACKGROUND AND OBJECTIVES:

Spinal muscular atrophy (SMA) was added to the Recommended Uniform Screening Panel (RUSP) in July 2018, largely on the basis of the availability and efficacy of newly-approved disease modifying therapies. New York State (NYS) started universal newborn screening for SMA in October 2018. The authors report the findings from the first 3 years of screening.

METHODS:

Statewide neonatal screening was conducted using DNA extracted from dried blood spots using a real-time quantitative polymerase chain reaction (qPCR) assay. Retrospective follow-up data were collected from 9 referral centers across the state on 34 infants.

RESULTS:

In the first three years since statewide implementation, nearly 650,000 infants have been screened for SMA. 34 babies screened positive and were referred to a neuromuscular specialty care center. The incidence remains lower than previously predicted. The majority (94%), including all infants with 2-3 copies of SMN2, have received treatment. Among treated infants, the overwhelming majority (97%; 29/30) have received gene replacement. All infants in this cohort with 3 copies of SMN2 are clinically asymptomatic post-treatment based on early clinical follow-up data. Infants with 2 copies of SMN2 are more variable in their outcomes. Electrodiagnostic outcomes data from a subgroup of patients (n=11) for whom pre- and post-treatment data demonstrated either improvement or no change in CMAP amplitude at last clinical follow-up compared to pre-treatment baseline. Most infants were treated before 6 weeks of age (median = 34.5 DOL; range 11-180). Delays and barriers to treatment identified by treating clinicians followed two broad themes: medical and non-medical. Medical delays most commonly reported were presence of AAV9 antibodies and elevated troponin I levels. Non-medical barriers included delays in obtaining insurance as well as insurance policies regarding specific treatment modalities.

DISCUSSION:

The findings from the NYS cohort of newborn screen-identified infants are consistent with other reports of improved outcomes from early diagnosis and treatment. Additional biomarkers of motor neuron health including electromyography can potentially be helpful in detecting pre-clinical decline.

• Authors: Bo Hoon Lee, Stella Deng, Claudia A Chiriboga, Denise M Kay, Obehioya Irumudomon, Emma Laureta, Leslie Delfiner, Simona O Treidler, Yaacov Anziska, Ai Sakonju, Chelsea Kois, Osman Farooq, Kristin Engelstad, Alexandra Laurenzano, Katherine Hogan, Michele Caggana, Carlos A Saavedra-Matiz, Colleen F Stevens, Emma Ciafaloni
• Journal: Neurology (Neurology) (Jul 14 2022) ISSN: 1526-632X [Electronic] United States
• PMID: 35835557 (Publication Type: Journal Article)
• Copyright: © 2022 American Academy of Neurology.