| Diagnosis | Omim Number | Sample Count |
| N-ACETYLGLUTAMATE SYNTHASE DEFICIENCY; NAGS DEFICIENCY | 237310 | 1 |
| NEMALINE MYOPATHY - TYPE UNKNOWN | | 2 |
| NEMALINE MYOPATHY 2, AUTOSOMAL RECESSIVE; NEM2 | 256030 | 26 |
| NEMALINE MYOPATHY 3; NEM3 | 161800 | 17 |
| NEMALINE MYOPATHY, AMISH TYPE; ANM | 605355 | 6 |
| NEPHROSIS 1, CONGENITAL, FINNISH TYPE; NPHS1 | 256300 | 4 |
| NESCAV SYNDROME; NESCAVS | | 7 |
| NEURAMINIDASE DEFICIENCY | 256550 | 12 |
| NEUROAXONAL DYSTROPHY, INFANTILE | 256600 | 6 |
| NEUROBLASTOMA; NB NEUROBLASTOMA SUPPRESSOR, INCLUDED; NBS, INCLUDED | 256700 | 2 |
| NEURODEGENERATION WITH BRAIN IRON ACCUMULATION 5; NBIA5 | | 18 |
| NEURODEGENERATIVE OVERLAP SYNDROME | | 3 |
| NEUROFIBROMATOSIS, TYPE I; NF1 | 162200 | 63 |
| NEUROFIBROMATOSIS, TYPE II; NF2 | 101000 | 8 |
| NEURONAL INTRANUCLEAR INCLUSION DISEASE | 603472 | 3 |
| NEUROPATHY, CONGENITAL SENSORY, WITH ANHIDROSIS | 256800 | 7 |
| NEUROPATHY, HEREDITARY SENSORY AND AUTONOMIC, TYPE III; HSAN3 | 223900 | 102 |
| NEUROPATHY, HEREDITARY, WITH LIABILITY TO PRESSURE PALSIES; HNPP | 162500 | 1 |
| NIEMANN-PICK DISEASE, TYPE A | 257200 | 9 |
| NIEMANN-PICK DISEASE, TYPE B | 607616 | 4 |
| NIEMANN-PICK DISEASE, TYPE C1; NPC1 | 257220 | 56 |
| NIEMANN-PICK DISEASE, TYPE C2 | 607625 | 4 |
| NIEMANN-PICK DISEASE: TYPE UNSPECIFIED | | 4 |
| NIJMEGEN BREAKAGE SYNDROME | 251260 | 26 |
| NODAL RHYTHM | 163800 | 13 |
| NON DYSTONIA SYNDROME | | 13 |
| NORRIE DISEASE; NDP - 310600 | 310600 | 3 |