This is a list of diseases starting with the letter "N".

• N acetyltransferase deficiency
• N syndrome
• N-Acetylglutamate synthase deficiency
• N-acetyl-alpha-D-galactosaminidase
• N-acetyl-glucosamine-6-sulfate sulfatase deficiency
• NADH CoQ reductase, deficiency of
• NADH cytochrome B5 reductase deficiency
• Naegeli–Franceschetti–Jadassohn syndrome
• Naguib syndrome
• Nail–patella syndrome
• Nakajo–Nishimura syndrome
• Nakajo syndrome
• Nakamura–Osame syndrome
• NAME syndrome
• Nance–Horan syndrome
• Nanism due to growth hormone combined deficiency
• Nanism due to growth hormone isolated deficiency with X-linked hypogammaglobulinemia
• Nanism due to growth hormone resistance
• Narcissistic personality disorder
• Narcolepsy

• Narcolepsy-Cataplexy

• Narrow oral fissure short stature cone shaped epiphyses
• Nasodigitoacoustic syndrome
• Nasopalpebral lipoma coloboma syndrome
• Nasopharyngeal carcinoma
• Nasopharyngeal teratoma Dandy–Walker diaphragmatic hernia
• Nasopharyngitis

• Natal teeth intestinal pseudoobstruction patent ductus
• Nathalie syndrome
• Native American myopathy
• Navajo poikiloderma
• Naxos disease

• Necrotizing encephalopathy, infantile subacute
• Necrotizing fasciitis
• Negative rheumatoid factor polyarthritis
• Neisseria meningitidis
• Nelson syndrome
• Nemaline myopathy
  • Nemaline myopathy, type 1
  • Nemaline myopathy, type 2
  • Nemaline myopathy, type 3
  • Nemaline myopathy, type 4
  • Nemaline myopathy, type 5
• Neonatal diabetes mellitus
  • Neonatal diabetes mellitus, permanent (PNDM)
  • Neonatal diabetes mellitus, transient (TNDM)
• Neonatal hemochromatosis
• Neonatal hepatitis
• Neonatal infection
• Neonatal herpes
• Neonatal ovarian cyst
• Neonatal transient jaundice

• Nephroblastomatosis, fetal ascites, macrosomia and Wilms' tumor
• Nephrocalcinosis
• Nephrogenic diabetes insipidus
• Nephrolithiasis type 2
• Nephronophthisis familial adult spastic q­riparesis
• Nephropathy deafness hyperparathyroidism
• Nephropathy familial with hyperuricemia
• Nephropathy, familial with gout
• Nephrosclerosis
• Nephrosis deafness urinary tract digital malformation
• Nephrosis neuronal dysmigration syndrome
• Nephrotic syndrome
• Nephrotic syndrome ocular anomalies
• Nephrotic syndrome, idiopathic, steroid-resistant
• Nerve sheath neoplasm
• Nesidioblastosis of pancreas
• Netherton syndrome ichthyosis

• Neu Laxova syndrome

• Neuhauser–Daly–Magnelli syndrome
• Neuhauser–Eichner–Opitz syndrome

• Neural crest tumor
• Neural tube defect, folate-sensitive
• Neural tube defects X linked
• Neuraminidase beta-galactosidase deficiency
• Neuraminidase deficiency
• Neurasthenia
• Neurilemmomatosis
• Neuritis with brachial predilection

• Neuroacanthocytosis
• Neuroaxonal dystrophy renal tubular acidosis
• Neuroaxonal dystrophy, late infantile
• Neuroblastoma
• Neurocutaneous melanosis
• Neurocysticercosis
• Neuroectodermal endocrine syndrome
• Neuroectodermal tumors primitive
• Neuroendocrine cancer
• Neuroendocrine carcinoma of the cervix
• Neuroendocrine tumor
• Neuroepithelioma
• Neurofaciodigitorenal syndrome
• Neurofibrillary tangles
• Neurofibroma
• Neurofibromatosis

• Neurofibromatosis type 2
• Neurofibromatosis type 3
• Neurofibromatosis type 6
• Neurofibromatosis, familial intestinal
• Neurofibromatosis, Type IV, of Riccardi
• Neurofibromatosis-Noonan syndrome

• Neurofibrosarcoma
• Neurogenic hypertension

• Neuroleptic malignant syndrome
• Neuroma biliary tract
• Neuromyotonia
• Neuronal ceroid lipofuscinosis
• Neuronal heterotopia
• Neuronal interstitial dysplasia
• Neuronal intestinal pseudoobstruction
• Neuronal intranuclear hyaline inclusion disease
• Neuronal intranuclear inclusion disease
• Neuropathy ataxia and retinis pigmentosa
• Neuropathy congenital sensory neurotrophic keratitis
• Neuropathy hereditary with liability to pressure palsies
• Neuropathy motor sensory type 2 deafness mental retardation
• Neuropathy sensory spastic paraplegia
• Neuropathy, hereditary motor and sensory, LOM type
• Neuropathy, hereditary sensory, type I
• Neuropathy, hereditary sensory, type II
• Neurosyphilis
• Neurotoxicity syndromes

• Neutral lipid storage myopathy
• Neutropenia intermittent
• Neutropenia monocytopenia deafness
• Neutropenia, severe chronic

• Nevi flammei, familial multiple
• Nevo syndrome
• Nevoid basal cell carcinoma syndrome
• Nevus of ota retinitis pigmentosa
• Nevus sebaceus of Jadassohn
• Nezelof syndrome

• Nicolaides–Baraitser syndrome
• Nicotine withdrawal
• Niemann–Pick disease

• Niemann–Pick C1 disease
• Niemann–Pick C2 disease
• Niemann–Pick disease, type C
• Niemann-Pick disease type D

• Night blindness

• Night blindness skeletal anomalies unusual facies
• Night blindness, congenital stationary

• Nijmegen breakage syndrome
• Nivelon–Nivelon–Mabille syndrome
• NMDA receptor antagonist neurotoxicity (NAN)

• Noble–Bass–Sherman syndrome
• Nocardiosis
• Noise-induced hearing loss
• Noma
• Non-24-hour sleep–wake disorder
• Non functioning pancreatic endocrine tumor
• Nonallergic atopic dermatitis
• Non-Hodgkin lymphoma
• Noninsulin-dependent diabetes mellitus with deafness
• Nonketotic hyperglycinemia
• Non-lissencephalic cortical dysplasia
• Nonmedullary thyroid carcinoma, with cell oxyphilia
• Nonne–Milroy disease
• Non-small cell lung cancer
• Nonsyndromic hereditary hearing impairment
• Nonvenereal endemic syphilis
• Nonverbal learning disorder
• Noonan like syndrome
• Noonan syndrome
• Norman–Roberts lissencephaly syndrome
• Normokalemic periodic paralysis
• Norrie disease
• Northern epilepsy syndrome
• Norum disease

• Nose polyposis, familial
• Notalgia paresthetica
• Nova syndrome
• Novak syndrome

• Nuchal bleb, familial
• Nut allergy
• Nyctophobia
• Nystagmus

• Nystagmus, central
• Nystagmus, peripheral
• Nystagmus with congenital zonular cataract