Introduction: Spinal muscular atrophy (SMA) and sporadic amyotrophic lateral sclerosis (SALS) are both motor neuron disorders. SMA results from the deletion of the survival motor neuron (SMN) 1 gene. High or low SMN1 copy number and the absence of SMN2 have been reported as risk factors for the development or severity of SALS. Objective: To investigate the role of SMN gene copy number in the onset and severity of SALS in Malians. Material and Methods: We determined the SMN1 and SMN2 copy number in genomic DNA samples from 391 Malian adult volunteers, 120 Yoruba from Nigeria, 120 Luyha from Kenya and 74 U.S. Caucasians using a Taqman quantitative PCR assay. We evaluated the SALS risk based on the estimated SMA protein level using the Veldink formula (SMN1 copy number + 0.2∗SMN2 copy number). We also characterized the disease natural history in 15 ALS patients at the teaching hospital of Point G, Bamako, Mali. Results: We found that 131 of 391 (33.5%) had an estimated SMN protein expression of ≤2.2; 60 out of 391 (15.3%) had an estimated SMN protein expression