| Diagnosis | Omim Number | Sample Count |
| REFSUM DISEASE | 266500 | 5 |
| REFSUM DISEASE, INFANTILE FORM | 266510 | 7 |
| RENAL ADYSPLASIA | 191830 | 2 |
| RENAL HAMARTOMAS, NEPHROBLASTOMATOSIS, AND FETAL GIGANTISM | 267000 | 3 |
| RETICULOSIS, FAMILIAL HISTIOCYTIC | 267700 | 4 |
| RETINITIS PIGMENTOSA - 180100, 268000, OR 312600 | 180100 | 28 |
| RETINITIS PIGMENTOSA - 180100, 268000, OR 312600 | 268000 | 28 |
| RETINITIS PIGMENTOSA - 180100, 268000, OR 312600 | 312600 | 28 |
| RETINITIS PIGMENTOSA 1; RP1 | 180100 | 145 |
| RETINITIS PIGMENTOSA 4; RP4 | | 3 |
| RETINITIS PIGMENTOSA; RP | 268000 | 5 |
| RETINOBLASTOMA, SPORADIC | 180200 | 13 |
| RETINOBLASTOMA; RB1 OSTEOSARCOMA, RETINOBLASTOMA-RELATED, INCLUDED | 180200 | 15 |
| RETT SYNDROME, CONGENITAL VARIANT | | 86 |
| RETT SYNDROME; RTT | 312750 | 86 |
| REYE SYNDROME | | 1 |
| RHESUS BLOOD GROUP, D ANTIGEN; RHD | 111680 | 2 |
| RHIZOMELIC CHONDRODYSPLASIA PUNCTATA, TYPE 1; RCDP1 | 215100 | 13 |
| RHIZOMELIC CHONDRODYSPLASIA PUNCTATA, TYPE 2; RCDP2 | 222765 | 4 |
| RHIZOMELIC CHONDRODYSPLASIA PUNCTATA, TYPE 3; RCDP3 | 600121 | 1 |
| RIGIDITY AND MULTIFOCAL SEIZURE SYNDROME, LETHAL NEONATAL; RMFSL | | 2 |
| ROBERTS SYNDROME; RBS | 268300 | 5 |
| ROKITANSKY-KUSTER-HAUSER SYNDROME | 277000 | 2 |
| ROTHMUND-THOMSON SYNDROME; RTS | 268400 | 18 |
| RUBINSTEIN-TAYBI SYNDROME; RSTS | 180849 | 2 |