SMN1 and proximal spinal muscular atrophy: Interestingly, this family was of African origin, a lineage in which the 2/0 genotype is quite frequent, and the mother was found to be heterozygous for the SMN1 c.*3+80T>G and c.*211_*212del polymorphisms, which have been associated with the SMN1 gene duplication, indicating a high risk of being a “silent” carrier of SMA [23].