Mustafa Komur, Ezgi Çağlar, İsmail Hakkı Akbeyaz, Ahmet Keçebaş, Edibe Pembegül Yıldız, Sema Saltık, Gamze Sarıkaya Uzan, Leman Tekin Orgun, Semra Erdogan, Gülten Öztürk, Gökçen Oz Tunçer, Özlem Yayıcı Köken, Esra Sarıgeçili, Seda Kanmaz, Didem Ardıçlı, Nezir Özgün, Gülçin Akıncı, Beril Dilber, Bilge Özgör, Kürşat Bora Çarman, Hüseyin Bahadır Şenol, Gülen Gul Mert, Çisem Duman Kayar, Yasemin Sancak, Burçin Gonullu Polat, Yiğithan Güzin, Elif Yıldırım, Serkan Kırık, Rabia Tütüncü Toker, Ayşe Aysima Özçelik, Gökce Cırdı, Sevda Asadova, Deniz Yüksel, Rojan İpek, Olcay Ünver, Ayşe Aksoy, Chakan Tsakır, Orhan Özdogan, Hülya Maraş Genç, Esma Sengenç, Gizem Dogan, Olcay Güngör, Ahmet Sami Güven, Dilek Çavuşoğlu, Sanem Keskin Yılmaz, Ezgi Erem, Aycan Ünalp, Elif Acar Arslan, Arife Derda Yücel Şen, Hüseyin Tan, Parvana Amrahova, Fatma Pınar Tabanlı, Meltem Cobanoğulları Direk, Hasan Gözen, Pınar Saka Ümit, Saliha Yavuz Eravcı, Habibe Uçar, Ömer Bektaş, Hüseyin Per, Ercan Demir, Ahmet Cevdet Ceylan, Uluç Yiş, Mihriban Özlem Hergüner, Hasan Tekgül, Dilşad Türkdoğan, Çetin Okuyaz
Spinal muscular atrophy (SMA) Type 1 in infants with two SMN2 copies is characterised by rapid motor neuron loss and a historically fatal course if untreated; however, nationwide real-world comparative data evaluating screening efficacy remain scarce. This nationwide retrospective, multicentre study evaluated the real-world impact of Turkey's national newborn screening (NBS) program on clinical outcomes in a high-risk population-of infants with genetically confirmed SMA and two SMN2 copies-treated with nusinersen. Patients were classified into a historical symptomatic cohort diagnosed before NBS implementation (pre-NBS, n = 162) and an NBS cohort identified through screening (n = 96); all received nusinersen. Outcomes included survival, respiratory and nutritional independence, and acquisition of WHO-defined motor milestones. Motor function was evaluated using the Children's Hospital of Philadelphia-Infant Test of Neuromuscular Disorders (CHOP-INTEND) scale. The NBS program markedly reduced the mean age at diagnosis and treatment initiation. Mortality was 6.3% in the NBS cohort compared with 30.9% in the pre-NBS group (p < 0.001). CHOP-INTEND scores at baseline were higher in the NBS cohort. Sustained motor gains were confirmed in both cohorts, though the NBS cohort maintained superior function throughout follow-up; 48.3% of NBS-identified infants achieved independent walking, compared with only 8.6% in the pre-NBS group. Preservation of bulbar and respiratory function was superior in the NBS cohort, whereas the pre-NBS group demonstrated progressive decline. NBS program fundamentally altered the clinical trajectory of SMA Type 1 in infants with two SMN2 copies in the present cohort. Pre-symptomatic treatment in the NBS cohort supports sustained motor development and preserves bulbar and respiratory functions, underscoring the importance of minimising delays between birth, diagnosis, and treatment initiation.