1 => Disorder placed on map based on association with a gene; defect unknown
2 => Disorder placed by linkage; no mutation found
3 => Molecular basis known; mutation found in gene
4 => Contiguous gene deletion/duplication syndrome
| Gene Symbol | Chromosomal Location | Gene MIM number | Mapping Method | Phenotype | Phenotype MIM number | Phenotype Mapping Key |
| PPM1K | 4q22.1 | 611065 | R, REc | ?Maple syrup urine disease, mild variant, 615135 (3) | 615135 | 3 |