Clinical Experience of Timing Treatment in Newborns with Spinal Muscular Atrophy: A Call for Standardized Screening Practices in Italy.

Abstract

Spinal muscular atrophy (SMA) is a rare neuromuscular disorder causing progressive muscle weakness. Severe SMA forms are typically observed up to six months postnatally. Disease-modifying therapies provide significant benefits, making newborn screening (NBS) essential for timely diagnosis and treatment initiation. The NBS programme evaluated infants born between April 2023 and October 2024 in the Campania region, Italy. DNA was amplified to detect homozygous deletion of the SMN1 gene by RT-PCR and SMN2 copy number using multiplex ligation-dependent probe amplification. Following treatment, motor functions were assessed using CHOP-INTEND and Bayley III scales. Among 62,801 infants screened for SMA, thirteen (11 females, 2 males) tested positive. The distribution of SMN2 copy numbers was as follows: eight patients had two copies, one patient had three, and four patients had four copies. One year after treatment, motor outcome data were available for four of the eight patients with two SMN2 copies. Among these patients, one achieved the milestones of walking without support, and three were standing with support. At 24 months, three of these patients were walking independently. Pre-symptomatic treatment markedly improves motor function development. This underscores the urgent need for large-scale newborn screening to prevent diagnostic delays and ensure timely, effective therapy. Validated care protocols must be established to facilitate early diagnosis and intervention.