PP09.1 – 2352: Systematic review of incidence and prevalence of spinal muscular atrophy (SMA)

Abstract

Objective Provide a summary of Spinal Muscular Atrophy (SMA) incidence and prevalence worldwide. Methods A systematic review of incidence and prevalence was conducted to identify estimates from peer-reviewed publications. SMA diagnostic criteria, definition of prevalence and incidence, geographic location, date of data collection, and population characteristics were noted. Incidence and prevalence estimates of SMA overall and by type are presented along with limitations. Results The PubMed search identified 27 population-based studies published between 1971 and 2014. Most publications focused on European populations (17) with the remaining in the Middle East (4), North America (2), Asia (1), South America (1), Africa (1), and Australia (1). Annual incidence for all types of SMA combined was estimated in 7 studies and ranged from 5.1 to 16.6 cases per 100,000 live births. By type, annual incidence per 100 000 live births ranged from 3.5 to 7.1 (with an outlier of 250 in a population of Egyptian Karaites in Israel) for type I, 1.0 to 5.3 for type II, and 1.5 to 4.6 for type III. Eight studies provided detailed overall prevalence estimates; however, these estimates varied by the population denominators that were applied. Point prevalence per 100 000 total population by SMA subtype ranged from 0.1 to 0.15 for type I, 0.57 to 0.67 for type II, and 0.64 to 1.05 for type III. Conclusion SMA is a rare disorder, with SMA type I having the highest incidence yet the lowest prevalence due to its higher mortality rate. Variations in diagnostic definition and population denominator used limit pooling of estimates across studies. More comprehensive, methodologically robust, and timely population-based incidence and prevalence measures are needed.