1 => The disorder is placed on the map based on its association with a gene, but the underlying defect is not known
2 => The disorder has been placed on the map by linkage; no mutation has been found
3 => The molecular basis for the disorder is known; a mutation has been found in the gene
4 => A contiguous gene deletion or duplication syndrome, multiple genes are deleted or duplicated causing the phenotype
| Gene Symbol | Chromosomal Location | Gene MIM number | Mapping Method | Phenotype | Phenotype MIM number | Phenotype Mapping Key |
| SMN1 | 5q13.2 | 600354 | REn | Spinal muscular atrophy-1, 253300 (3) | 253300 | 3 |
| SMN1 | 5q13.2 | 600354 | REn | Spinal muscular atrophy-2, 253550 (3) | 253550 | 3 |
| SMN1 | 5q13.2 | 600354 | REn | Spinal muscular atrophy-3, 253400 (3) | 253400 | 3 |
| SMN1 | 5q13.2 | 600354 | REn | Spinal muscular atrophy-4, 271150 (3) | 271150 | 3 |