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 |
| GNB1 | 1p36.33 | 139380 | REa, A | Mental retardation, autosomal dominant 42, 616973 (3) | 616973 | 3 |
| GNB1 | 1p36.33 | 139380 | REa, A | Leukemia, acute lymphoblastic, somatic, 613065 (3) | 613065 | 3 |