A disease or disorder is defined as rare in Europe when it affects fewer than 1 in 2000. A disease or disorder is defined as rare in the USA when it affects fewer than 200,000 persons at any given time. Here we take the European definition to be consistent with Orphanet.

rare (European definition)

MONDO:0021136

• intestinal obstruction in the newborn due to guanylate cyclase 2C deficiency
• congenital diarrhea 6
• formaldehyde poisoning
• florid cystic endosalpingiosis of the uterus
• infection due to clostridium perfringens
• PHGDH deficiency
• DDOST-congenital disorder of glycosylation
• graft versus host disease
• Graham-Boyle-Troxell syndrome
• H syndrome
• polyarticular juvenile rheumatoid arthritis
• malignant atrophic papulosis
• toxic shock syndrome
• hemochromatosis type 3
• Chudley-McCullough syndrome
• pityriasis rotunda
• neuronal intranuclear inclusion disease
• heavy metal poisoning
• macrocephaly-autism syndrome
• Huntington disease-like 3
• hereditary spastic paraplegia 11
• juvenile idiopathic arthritis
• Weber syndrome
• MOGS-congenital disorder of glycosylation
• hemochromatosis type 4
• congenital myotonic dystrophy
• C1q nephropathy
• prostate phyllodes tumor
• odontomatosis-aortae esophagus stenosis syndrome
• neoplastic syndrome
• familial multiple nevi flammei
• hematohidrosis
• neurologic, endocrine, and pancreatic disease, multisystem, infantile-onset 1
• familial spontaneous pneumothorax
• melanoma associated retinopathy
• piebaldism
• prolidase deficiency
• pseudoleprechaunism syndrome, Patterson type
• migraine with or without aura, susceptibility to, 6
• HTLV-2 infection
• hereditary chronic pancreatitis
• ovarian fibroma
• otofaciocervical syndrome
• Amish lethal microcephaly
• anonychia-microcephaly syndrome
• Dowling-Degos disease
• pruritic urticarial papules and plaques of pregnancy
• radial hypoplasia-triphalangeal thumbs-hypospadias-maxillary diastema syndrome
• leishmaniasis
• cataract - congenital heart disease - neural tube defect syndrome
• short stature-craniofacial anomalies-genital hypoplasia syndrome
• ALG8-congenital disorder of glycosylation
• ovarian hyperstimulation syndrome
• sweet syndrome
• autosomal dominant prognathism
• ALG2-congenital disorder of glycosylation
• tufted angioma
• craniolenticulosutural dysplasia
• subacute cutaneous lupus erythematosus
• chronic cutaneous lupus erythematosus
• cap polyposis
• hemophagocytic syndrome
• epithelioid hemangioendothelioma
• genetic parenchymatous liver disease
• genetic biliary tract disease
• genetic endocrine growth disease
• genetic hypertension
• facial arteriovenous malformation
• microcephaly-facio-cardio-skeletal syndrome, Hadziselimovic type
• lethal polymalformative syndrome, Boissel type
• primary peritoneal tumor
• childhood disintegrative disorder
• chronic thromboembolic pulmonary hypertension
• distomatosis
• epilepsy syndrome
• monogenic epilepsy
• porokeratotic eccrine ostial and dermal duct nevus
• rectum neuroendocrine neoplasm
• advanced sleep phase syndrome
• pancreatic serous cystadenocarcinoma
• polymicrogyria with optic nerve hypoplasia
• undifferentiated embryonal sarcoma of the liver
• inflammatory myofibroblastic tumor
• Nijmegen breakage syndrome-like disorder
• adult hypothyroidism
• cholera
• intellectual disability-cataracts-kyphosis syndrome
• microcephaly-polymicrogyria-corpus callosum agenesis syndrome
• periventricular leukomalacia
• idiopathic bilateral vestibulopathy
• major hypertriglyceridemia
• COG4-congenital disorder of glycosylation
• alpha 1-antitrypsin deficiency
• Warsaw breakage syndrome
• cirrhosis - dystonia - polycythemia - hypermanganesemia syndrome
• benign breast phyllodes tumor
• giant adenofibroma of the breast
• Paget disease of the nipple
• benign ductal tumor of breast