Diagnostic Journey of Korean Patients with Spinal Muscular Atrophy.

Purpose: Spinal muscular atrophy (SMA) is an autosomal recessive genetic disease characterized by the loss of motor neurons in the spinal cord and brainstem, leading to muscle atrophy and weakness. To understand the diagnostic process of Korean patients with SMA, we analyzed their clinical characteristics and challenges.

Materials and methods: We conducted a retrospective study of 38 patients with SMA (9 type II and 29 type III) between January 2000 and September 2023. Clinical, laboratory, and genetic data were reviewed.

Results: The median ages at symptom onset and diagnosis were 3.0 years [interquartile range (IQR): 1.0-7.3 years] and 25.0 years (IQR: 10.5-37.3 years), respectively. The median diagnostic delay was 19.6 years (IQR: 6.4-31.0 years). A significantly longer delay was observed in SMA type III patients (median: 21.0 years, IQR: 11.0-31.0 years) compared to SMA type II patients (median: 3.0 years, IQR: 0.9-21.0 years) (p=0.021). No significant difference was observed in the number of clinic visits before diagnosis between patients with SMA type II (median: 2.0, IQR: 1.0-4.5) and those with type III (median: 2.0, IQR: 2.0-6.0, p=0.282). The number of clinic visits before diagnosis showed no significant association with the age at symptom onset and diagnosis (p=0.998 and 0.291, respectively).

Conclusion: Our investigation is the first examination of the diagnostic journey of Korean patients with SMA. As treatments for SMA progress, the significance of an accurate diagnosis has increased, highlighting the importance of reviewing the diagnostic advancements made thus far.