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Diseases

Genetic and Rare Diseases Information Center (GARD)

Search for Rare or Genetic Diseases


Diseases Beginning With I

The purpose of the Rare Diseases and Related Terms list is to distribute information; although the list is updated regularly, it should not be used as a reference or guarantee that a condition is rare. The prevalence of a rare disease is usually an estimate and may change over time. A rare (or orphan) disease is generally considered to have a prevalence of fewer than 200,000 affected individuals in the United States.

* This symbol indicates that a condition is not rare but is one for which a question has been answered by the GARD Information Center.
Is Rare Condition? Disease Name
* I cell disease
* I(Y)(p10) - See Isochromosome Yp
* I2S deficiency - See Mucopolysaccharidosis type II
* IAHSP - See Infantile-onset ascending hereditary spastic paralysis
* IBD deficiency - See Isobutyryl-CoA dehydrogenase deficiency
* IBGC childhood onset - See Idiopathic basal ganglia calcification childhood-onset
* IBGC1 - See Familial idiopathic basal ganglia calcification
* IBIDS syndrome
* IBM - See Inclusion body myositis
* IBM2 - See Inclusion body myopathy 2
* IBM3 - See Inclusion body myopathy 3
* IBMPFD - See Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia
* IBS - See Ichthyosis bullosa of Siemens
* IBSN - See Striatonigral degeneration infantile
*   IC - See Interstitial cystitis
* ICCA - See Infantile convulsions and paroxysmal choreoathetosis, familial
* ICCA syndrome - See Infantile convulsions and paroxysmal choreoathetosis, familial
* ICD - See I cell disease
* ICE syndrome - See Iridocorneal endothelial syndrome
* ICF syndrome
* Ichthyosiform erythroderma with leukocyte vacuolation - See Chanarin-Dorfman syndrome
* Ichthyosiform erythroderma, Brocq congenital, nonbullous form - See Nonbullous congenital ichthyosiform erythroderma
* Ichthyosiform erythroderma, congenital, nonbullous, 1 - See Nonbullous congenital ichthyosiform erythroderma
* Ichthyosiform erythroderma, corneal involvement, deafness
* Ichthyosis - male hypogonadism - See Ichthyosis and male hypogonadism
* Ichthyosis acquisita - See Ichthyosis, acquired
* Ichthyosis alopecia eclabion ectropion mental retardation
* Ichthyosis and male hypogonadism
* Ichthyosis bullosa of Siemens
* Ichthyosis cheek eyebrow syndrome
* Ichthyosis congenita - See Ichthyosis lamellar 1
* Ichthyosis congenita biliary atresia
* Ichthyosis congenita IIB - See Ichthyosis lamellar 2
* Ichthyosis congenita III - See Ichthyosis lamellar 3
* Ichthyosis congenita IV - See Ichthyosis prematurity syndrome
* Ichthyosis congenita, Harlequin fetus type - See Harlequin ichthyosis
* Ichthyosis congenita, neurosensory deafness, oligophrenia, dental aplasia, brachydactyly, clinodactyly, accessory cervical ribs and thyroid carcinoma - See Ruzicka Goerz Anton syndrome
* Ichthyosis deafness mental retardation skeletal anomalies - See Ruzicka Goerz Anton syndrome
* Ichthyosis deafness mental retardation skeletal anomaly
* Ichthyosis follicularis atrichia photophobia syndrome
* Ichthyosis hystrix gravior
* Ichthyosis hystrix, Curth Macklin type
* Ichthyosis intellectual deficit dwarfism renal impairment - See Ichthyosis, mental retardation, dwarfism and renal impairment
* Ichthyosis lamellar 1
* Ichthyosis lamellar 2
* Ichthyosis lamellar 3
* Ichthyosis lamellar, autosomal dominant
* Ichthyosis linearis circumflexa
* Ichthyosis male hypogonadism - See Ichthyosis and male hypogonadism
* Ichthyosis mental retardation dwarfism renal impairment
* Ichthyosis prematurity syndrome
* Ichthyosis simplex - See Ichthyosis vulgaris
* Ichthyosis tapered fingers midline groove up
* Ichthyosis vulgaris
* Ichthyosis with hypotrichosis, autosomal recessive
* Ichthyosis, acquired
* Ichthyosis, bilateral cryptorchidism, hypogenitalism and mental retardation - See Ichthyosis and male hypogonadism
* Ichthyosis, bullous type - See Ichthyosis bullosa of Siemens
* Ichthyosis, CHILD syndrome - See CHILD syndrome
* Ichthyosis, erythrokeratolysis hemalis
* Ichthyosis, follicular
* Ichthyosis, hepatosplenomegaly, and cerebellar degeneration - See Dykes Markes Harper syndrome
* Ichthyosis, leukocyte vacuoles, alopecia, and sclerosing cholangitis
* Ichthyosis, mental retardation and asymptomatic spasticity - See Koone Rizzo Elias syndrome
* Ichthyosis, mental retardation, dwarfism and renal impairment
* Ichthyosis, spastic neurologic disorder, and oligophrenia - See Sjogren-Larsson syndrome
* Ichthyosis-mental retardation syndrome with large keratohyalin granules in the skin
* Ichthyosis-sclerosing cholangitis syndrome - See Ichthyosis, leukocyte vacuoles, alopecia, and sclerosing cholangitis
* Ichtyosis, Brittle hair, Intellectual impairment, Decreased fertility, and Short stature - See IBIDS syndrome
* ICP - See Intrahepatic cholestasis of pregnancy
* ICR2B - See Ichthyosis lamellar 2
* ICS - See Primary ciliary dyskinesia
* Icterohemorrhagic fever - See Leptospirosis
*   IDD - See Intervertebral disc disease
*   IDDM - See Diabetes mellitus type 1
* IDDM secretory diarrhea syndrome - See Immunodysregulation, polyendocrinopathy and enteropathy X-linked
* IDDM-MED syndrome - See Epiphyseal dysplasia multiple with early-onset diabetes mellitus
* IDF - See Infantile digital fibromatosis
* Idic(15) - See Isodicentric chromosome 15 syndrome
* Idiopathic acute eosinophilic pneumonia
* Idiopathic adolescent scoliosis
* Idiopathic alveolar hypoventilation syndrome
* Idiopathic aplastic anemia - See Aplastic anemia
* Idiopathic atrophoderma of Pasini and Pierini - See Atrophoderma of Pierini and Pasini
* Idiopathic autoimmune hemolytic anemia - See Autoimmune hemolytic anemia
* Idiopathic basal ganglia calcification 1 - See Familial idiopathic basal ganglia calcification
* Idiopathic basal ganglia calcification childhood-onset
* Idiopathic BOOP - See Cryptogenic organizing pneumonia
* Idiopathic bronchiolitis obliterans organizing pneumonia - See Cryptogenic organizing pneumonia
* Idiopathic calciphylaxis - See Calciphylaxis
* Idiopathic catastrophic epileptic encephalopathy - See Febrile infection-related epilepsy syndrome
* Idiopathic CD4 positive T-lymphocytopenia - See T-Lymphocytopenia
* Idiopathic CD4+ Lymphocytopenia - See Absent T lymphocytes
* Idiopathic chronic, erosive gastritis - See Chronic erosive gastritis
* Idiopathic congenital central alveolar hypoventilation - See Congenital central hypoventilation syndrome
* Idiopathic congestive splenomegaly - See Banti's syndrome
*   Idiopathic cyclic edema - See Idiopathic edema
* Idiopathic De Toni-Debre-Fanconi syndrome - See Toni-Debre-Fanconi syndrome
* Idiopathic diffuse interstitial fibrosis
* Idiopathic dilatation of the pulmonary artery
* Idiopathic dilated cardiomyopathy - See Dilated cardiomyopathy
* Idiopathic double athetosis
* Idiopathic dystonia DYT1 - See Dystonia 1
*   Idiopathic edema
* Idiopathic eosinophilic chronic pneumopathy
* Idiopathic erythema nodosum - See Erythema nodosum, idiopathic
* Idiopathic facial palsy - See Bell's palsy
* Idiopathic familial premature ovarian failure - See Premature ovarian failure, familial
* Idiopathic giant-cell myocarditis - See Giant cell myocarditis
* Idiopathic gigantomastia (subtype) - See Gigantomastia
* Idiopathic granulomatous hypophysitis - See Granulomatous hypophysitis
* Idiopathic hydrops fetalis - See Hydrops fetalis
* Idiopathic hypercalciuria with bilateral macular colobomata - See Meier Blumberg Imahorn syndrome
* Idiopathic hypersomnia - See Idiopathic hypersomnolence
* Idiopathic hypersomnolence - See Idiopathic hypersomnolence
* Idiopathic hypersomnolence
* Idiopathic hypertrophic osteoarthropathy - See Pachydermoperiostosis
* Idiopathic hypertrophic subaortic stenosis - See Familial hypertrophic cardiomyopathy
* Idiopathic infantile arterial calcification - See Arterial calcification of infancy
* Idiopathic inflammatory myopathy - See Idiopathic myopathy
* Idiopathic inflammatory myopathy, familial - See Idiopathic myopathy
* Idiopathic interstitial pneumonitis - from asbestos exposure - See Asbestosis
* Idiopathic intracranial hypertension - See Pseudotumor cerebri
* Idiopathic juvenile osteoporosis - See Juvenile osteoporosis
* Idiopathic juxtafoveal retinal telangiectasia
* Idiopathic juxtafoveal retinal telangiectasis - See Idiopathic juxtafoveal retinal telangiectasia
* Idiopathic juxtafoveal telangiectasis - See Idiopathic juxtafoveal retinal telangiectasia
* Idiopathic macular telangiectasia - See Idiopathic juxtafoveal retinal telangiectasia
* Idiopathic mediastinal fibrosis - See Fibrosing mediastinitis
* Idiopathic membranous nephropathy - See Membranous nephropathy
* Idiopathic minimal change nephrotic syndrome - See Minimal change disease
* Idiopathic multicentric Castleman's disease - See Multicentric Castleman’s Disease
* Idiopathic myelofibrosis - See Myelofibrosis
* Idiopathic myeloid splenomegaly - See Myeloid splenomegaly
* Idiopathic myopathy
* Idiopathic neonatal Hemochromatosis - See Neonatal hemochromatosis
*   Idiopathic neutropenia
* Idiopathic obliterative vasculopathy - See Eales disease
*   Idiopathic orthostatic edema - See Idiopathic edema
* Idiopathic orthostatic hypotension (a symptom) - See Pure autonomic failure
* Idiopathic perniosis - See Perniosis
* Idiopathic portal hypertension - See Banti's syndrome
* Idiopathic pulmonary arterial hypertension - See Pulmonary arterial hypertension
* Idiopathic pulmonary fibrosis
* Idiopathic pulmonary hemosiderosis
* Idiopathic pulmonary hypertension - See Pulmonary arterial hypertension
* Idiopathic pure red cell aplasia - See Acquired pure red cell aplasia
* Idiopathic recurrent vitreal hemorrhage - See Eales disease
* Idiopathic retroperitoneal fibrosis - See Retroperitoneal fibrosis
* Idiopathic sclerosing mesenteritis - See Sclerosing mesenteritis
* Idiopathic sexual precocity - See Precocious puberty
* Idiopathic spinal cord herniation
* Idiopathic subglottic tracheal stenosis
* Idiopathic thrombocythemia - See Essential thrombocythemia
* Idiopathic thrombocytopenic purpura
* Idiopathic thrombotic thrombocytopenic purpura - See Thrombotic thrombocytopenic purpura, acquired
* Idiopathic torsion dystonia - See Dystonia 1
* Idiopathic tropical malabsorption syndrome - See Tropical sprue
* Idiopathic ventricular fibrillation - See Paroxysmal ventricular fibrillation
* IDMDC - See Spastic paraplegia 18
* IDUA deficiency - See Mucopolysaccharidosis type I
* Iduronate 2-sulfatase deficiency - See Mucopolysaccharidosis type II
* IED - See Tufting enteropathy
* Ieshima Koeda Inagaki syndrome - See Mental retardation short stature deafness genital
* IFAP syndrome - See Ichthyosis follicularis atrichia photophobia syndrome
* IFD - See Intrinsic factor deficiency
* IFNGR1 deficiency - See Interferon gamma, receptor 1, deficiency
* IGA nephropathy - See Berger disease
* IgA, selective deficiency of - See Selective IgA deficiency
* IgA, selective deficiency of, TACI related - See Immunoglobulin A deficiency 2
* IGAD1 - See Selective IgA deficiency
* IGAD2 - See Immunoglobulin A deficiency 2
* IGAN - See Berger disease
* IGDA - See Iridogoniodysgenesis type1
* IGDA syndrome - See Iridogoniodysgenesis type1
* IGDS - See Iridogoniodysgenesis, dominant type
* IGF1 deficiency - See Insulin-like growth factor I deficiency
* IGF-1 resistance - See Insulin-like growth factor 1 resistance to
*   IgG deficiency - See Immunoglobulin G deficiency
* IgG heavy chain disease - See Gamma heavy chain disease
*   IgG subclass deficiency - See Immunoglobulin G deficiency
* IGHD 1B - See Isolated growth hormone deficiency type 1B
* IGHD IA - See Isolated growth hormone deficiency type 1A
* IGHD II - See Isolated growth hormone deficiency type 2
* IGHD III - See Isolated growth hormone deficiency type 3
* IGHD1A - See Isolated growth hormone deficiency type 1A
* IGHD1B - See Isolated growth hormone deficiency type 1B
* IGHD2 - See Isolated growth hormone deficiency type 2
* IGHD3 - See Isolated growth hormone deficiency type 3
* IGS - See Imerslund-Grasbeck syndrome
* IHCM - See Ichthyosis hystrix, Curth Macklin type
* IHG - See Iris hypoplasia and glaucoma
* IHGA - See Iridogoniodysgenesis, dominant type
* IHIS - See Immunodeficiency with hyper IgM type 1
* IIAC - See Arterial calcification of infancy
* Iida Kannari syndrome
* IIM - See Idiopathic myopathy
* IJO - See Juvenile osteoporosis
* IJT - See Idiopathic juxtafoveal retinal telangiectasia
* IL-12Râ1 deficiency - See IL12RB1 deficiency
* IL12RB1 deficiency
*   Ileitis - See Crohn's disease
* Iliac vein compression syndrome - See May–Thurner syndrome
* Iliocaval compression syndrome - See May–Thurner syndrome
* ILLIG type growth hormone deficiency - See Isolated growth hormone deficiency type 1A
* Illium syndrome - See Arthrogryposis multiplex congenita whistling face
* Illum syndrome
* ILS - See Lissencephaly 1
* ILVASC - See Ichthyosis, leukocyte vacuoles, alopecia, and sclerosing cholangitis
* ILVEN - See Inflammatory linear verrucous epidermal nevus
* Imaizumi Kuroki syndrome
* IMD 2 - See Wiskott Aldrich syndrome
* Imerslund-Grasbeck syndrome
* Imidodipeptidase deficiency - See Prolidase deficiency
* Iminoglycinuria
* Immotile cilia syndrome - See Primary ciliary dyskinesia
* Immotile cilia syndrome due to excessively long cilia - See Ciliary dyskinesia with excessively long cilia
* Immotile cilia syndrome, due to defective radial spokes
* Immune defect due to absence of thymus
* Immune deficiency, familial variable
* Immune deficiency, variable, with centromeric instability of chromosomes 1, 9, and 16 - See ICF syndrome
* Immune dysfunction with T-cell inactivation due to calcium entry defect 1
* Immune dysfunction with T-cell inactivation due to calcium entry defect 2
* Immune thrombocytopenia
* Immunoblastic lymphadenopathy - See Angioimmunoblastic T-cell lymphoma
* Immunodeficiency 2 - See Wiskott Aldrich syndrome
* Immunodeficiency syndrome, variable - See ICF syndrome
* Immunodeficiency with ataxia telangiectasia - See Ataxia telangiectasia
* Immunodeficiency with cleft lip/palate, cataract, hypopigmentation and absent corpus callosum - See Vici syndrome
* Immunodeficiency with hyper IgM type 1
* Immunodeficiency with hyper IgM type 2
* Immunodeficiency with hyper IgM type 3
* Immunodeficiency with hyper IgM type 4
* Immunodeficiency with hyper IgM type 5
* Immunodeficiency with thymoma - See Good syndrome
* Immunodeficiency without anhidrotic ectodermal dysplasia
* Immunodeficiency, isolated - See Immunodeficiency without anhidrotic ectodermal dysplasia
* Immunodeficiency, microcephaly with normal intelligence
* Immunodeficiency, pure - See Immunodeficiency without anhidrotic ectodermal dysplasia
* Immunodeficiency, X-linked, with magnesium defect, epstein-barr virus infection, and neoplasia - See X-linked magnesium deficiency with Epstein-Barr virus infection and neoplasia
* Immunodeficiency-centromeric instability-facial anomalies syndrome - See ICF syndrome
* Immunodysregulation, polyendocrinopathy and enteropathy X-linked
* Immunoglobulin A deficiency 1 - See Selective IgA deficiency
* Immunoglobulin A deficiency 2
* Immunoglobulin A, selective deficiency of - See Selective IgA deficiency
* Immunoglobulin A, selective deficiency of, TACI related - See Immunoglobulin A deficiency 2
* Immunoglobulin Deficiency - See Primary agammaglobulinemia
* Immunoglobulin deficiency, late-onset - See Common variable immunodeficiency
*   Immunoglobulin G deficiency
* Immuno-hemolytic anemia - See Autoimmune hemolytic anemia
* Immunologic deficiency, pancytopenia, and cutaneous malignancies - See Fanconi like syndrome
* Immunoosseous dysplasia, schimke type - See Schimke immunoosseous dysplasia
* Immunotactoid glomerulopathy
* Impairment of oral perception
* Imperforate anus
* Imperforate oropharynx-costo vetebral anomalies
* Impossible syndrome - See Chondrodysplasia situs inversus imperforate anus polydactyly
* Impuberism and anovulation due to resistance to LH - See Resistance to LH (luteinizing hormone)
* INAD - See Neuroaxonal dystrophy, infantile
*   Inappropriate ADH syndrome - See Syndrome of inappropriate antidiuretic hormone
* Inborn amino acid metabolism disorder
* Inborn error of urea synthesis, arginino succinic type - See Argininosuccinic aciduria
* Inborn renal aminoaciduria
* Incisors fused - See Single upper central incisor
* Inclusion body myopathy 2
* Inclusion body myopathy 3
* Inclusion body myopathy autosomal dominant - See Inclusion body myopathy 3
* Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia
* Inclusion body myopathy with Paget disease of bone and frontotemporal dementia - See Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia
* Inclusion body myopathy, autosomal recessive - See Inclusion body myopathy 2
* Inclusion body myopathy, quadriceps-sparing - See Inclusion body myopathy 2
* Inclusion body myositis
* Inclusion cell disease - See I cell disease
* Inclusion conjunctivitis
* Incomplete achromatopsia X-linked - See Blue cone monochromatism
* Incomplete lissencephaly - See Partial lissencephaly
* Incontinentia pigmenti
* Incontinentia pigmenti achromians - See Hypomelanosis of Ito
* Incontinentia pigmenti type 1 (formerly) - See Hypomelanosis of Ito
* Incontinentia pigmenti type 2 (formerly) - See Incontinentia pigmenti
* Incontinentia pigmenti, familial male-lethal type - See Incontinentia pigmenti
* Increased aromatase activity - See Aromatase deficiency
* Increased-permeability pulmonary edema - See Acute respiratory distress syndrome
* Index finger anomaly with Pierre Robin syndrome - See Catel Manzke syndrome
* Indolent B cell lymphoma
* Indolent systemic mastocytosis - See Systemic mastocytosis
* Indomethacin antenatal infection
* Infant botulism (subtype) - See Botulism
* Infant epilepsy with migrant focal crisis
* Infantile apnea
* Infantile axonal neuropathy
* Infantile bilateral striatal necrosis - See Striatonigral degeneration infantile
* Infantile cerebellooptic atrophy - See PEHO syndrome
* Infantile CLN (type of CLN1) - See Ceroid lipofuscinosis neuronal 1
* Infantile convulsions and paroxysmal choreoathetosis, familial
* Infantile cortical hyperostosis - See Caffey disease
* Infantile digital fibromatosis
* Infantile form of phytanic acid storage disease - See Refsum disease, infantile form
* Infantile free sialic acid storage disease
* Infantile fucosidosis - See Fucosidosis type 1
* Infantile histiocytoid cardiomyopathy
* Infantile myofibromatosis
* Infantile neuroaxonal dystrophy - See Neuroaxonal dystrophy, infantile
* Infantile Onset Multisystem Inflammatory Disease - See Chronic Infantile Neurological Cutaneous Articular syndrome
* Infantile onset spinocerebellar ataxia
* Infantile paralysis - See Poliomyelitis
* Infantile Parkinsonism-dystonia
* Infantile poliodystrophy - See Alpers syndrome
* Infantile polymyoclonus - See Dancing eyes-dancing feet syndrome
* Infantile progressive spinal muscular atrophy with ophthalmoplegia and pyramidal symptoms - See Spinal atrophy ophthalmoplegia pyramidal syndrome
* Infantile recurrent chronic multifocal osteomyolitis
* Infantile Refsum disease - See Refsum disease, infantile form
* Infantile respiratory distress syndrome - See Respiratory distress syndrome, infant
* Infantile scoliosis
* Infantile sialic acid storage disorder - See Infantile free sialic acid storage disease
* Infantile spasm - See West syndrome
* Infantile spasms broad thumbs
* Infantile striato thalamic degeneration
* Infantile systemic hyalinosis - See Juvenile hyaline fibromatosis
* Infantile thoracic dystrophy - See Jeune syndrome
* Infantile xanthomatous cardiomyopathy - See Infantile histiocytoid cardiomyopathy
* Infantile-onset ascending hereditary spastic paralysis
* Infantile-onset symptomatic epilepsy syndrome - developmental stagnation - blindness - See Amish infantile epilepsy syndrome
* Infarct of the spleen - See Splenic infarcts
* Infection due to cat liver fluke - See Opisthorchiasis
* Infection due to Opisthorchis (felineus)(viverrini) - See Opisthorchiasis
* Infection with trichinella - See Trichinosis
* Infectious arthritis
* Infectious myocarditis
* Infective endocarditis
* Infective myositis
* Inflammation of the whole uveal tract - See Panuveitis
* Inflammatory breast cancer
* Inflammatory fibrosarcoma - See Inflammatory myofibroblastic tumor
* Inflammatory linear verrucous epidermal naevus - See Inflammatory linear verrucous epidermal nevus
* Inflammatory linear verrucous epidermal nevus - See Inflammatory linear verrucous epidermal nevus
* Inflammatory linear verrucous epidermal nevus
* Inflammatory myofibroblastic tumor
* Inflammatory myopathy - See Inclusion body myositis
* Inflammatory occlusive peripheral vascular disease - See Buerger disease
* Inflammatory pseudotumor - See Inflammatory myofibroblastic tumor
* Inflammatory Rheumatism - See Rheumatic Fever
* Infundibulopelvic dysgenesis
* Inhalation of barytes - See Baritosis
*   Inherited bone marrow failure syndromes
* Inherited congenital bilateral atresia of the external auditory canal, congenital bilateral vertical talus and increased interocular distance - See Rasmussen Johnsen Thomsen syndrome
* Inherited hypoprothrombinemia
* Inherited peripheral neuropathy
* Inherited prothrombin deficiency - See Inherited hypoprothrombinemia
* Iniencephaly
* Insensitivity to pain, congenital, with anhidrosis - See Congenital insensitivity to pain with anhidrosis
* Insley-Astley syndrome - See OSMED Syndrome
* Insomnia familial fatal - See Fatal familial insomnia
* Instituto Venezolano de Investigaciones Cientificas syndrome - See IVIC syndrome
* Insulin autoimmune syndrome
*   Insulin-dependent diabetes mellitus - See Diabetes mellitus type 1
* Insulin-like growth factor 1 resistance to
* Insulin-like growth factor I deficiency
* Insulinoma
* Insulin-resistance type B
* Insulin-resistant acanthosis nigricans, type A
* Insulin-resistant diabetes with acanthosis nigricans, hypogonadism, pigmentary retinopathy, deafness, and mental retardation - See Retinitis pigmentosa, deafness, mental retardation, and hypogonadism
* Intellectual deficit - short stature - hypertelorism
* Intellectual deficit - unusual facies - See Morillo-Cucci-Passarge syndrome
* Intellectual deficit Buenos-Aires type
* Intellectual deficit unusual facies talipes hand anomalies
* Intellectual deficit X-linked Siderius type - See Siderius X-linked mental retardation syndrome
* Intellectual deficit, X-linked - psychosis - macroorchidism - See PPM-X syndrome
* Intellectual disability with absent fifth fingernail and terminal phalanx - See Coffin-Siris syndrome
* Intellectual disability, autosomal recessive 18 - See MED23
* Intellectual disability, deafness, skeletal abnormalities, coarse face with full lips - See Fountain syndrome
* Intellectual disability, motor dysfunction, and joint contractures - See Spastic paraplegia 18
* Intellecutal disability with postaxial polydactyly, congenital absence of hair, severe seborrhoeic dermatitis, and Perthes' disease of the hip - See Garret Tripp syndrome
* Intercellular cholesterol esterification disease
* Interferon gamma, receptor 1, deficiency
* Interleukin 1 receptor antagonist deficiency - See Deficiency of interleukin-1 receptor antagonist
* Interleukin receptor-associated kinase deficiency - See IRAK-4 deficiency
* Intermediate Salla disease - See Intermediate severe Salla disease
* Intermediate severe Salla disease
* Intermediate uveitis - See Pars planitis
* Internal carotid agenesis
* Internal carotid artery agenesis - See Internal carotid agenesis
* Interstitial 16p13.3 duplication - See Chromosome 16p13.3 duplication
*   Interstitial cystitis
* Interstitial megalocytic nephritis - See Megalocytic interstitial nephritis
*   Intervertebral disc degeneration - See Intervertebral disc disease
*   Intervertebral disc disease
* Intestinal amebiasis - See Amebiasis
* Intestinal atresia multiple
* Intestinal epithelial dysplasia - See Tufting enteropathy
* Intestinal fructose intolerance - See Acquired fructose intolerance
* Intestinal helminthiasis - See Helminthiasis
* Intestinal hypoganglionosis - See Hypoganglionosis
* Intestinal lipodystrophy - See Whipple disease
* Intestinal lipophagic granulomatosis - See Whipple disease
* Intestinal lymphagiectasia lymphedema intellectual deficit syndrome - See Hennekam syndrome
* Intestinal malrotation facial anomalies familial type - See Stalker Chitayat syndrome
* Intestinal polyposis, osteomas, sebaceous cysts - See Gardner syndrome
* Intestinal pseudoobstruction - See Intestinal pseudo-obstruction
* Intestinal pseudo-obstruction
* Intestinal pseudoobstruction due to neuronal disease - See Visceral neuropathy familial
* Intestinal pseudoobstruction neuronal chronic idiopathic X-linked
* Intestinal pseudoobstruction with external ophthalmoplegia - See Familial visceral myopathy with external ophthalmoplegia
* Intestinal Pseudoobstruction with Patent Ductus Arteriosus and Natal Teeth - See Natal teeth, intestinal pseudoobstruction and patent ductus
* Intracardiac myxoma - See Atrial myxoma, familial
* Intracavitary tumors - See Heart tumor
* Intracortical fibrous dysplasia - See Osteofibrous dysplasia
* Intracranial aneurysms multiple congenital anomaly
* Intracranial arachnoid cysts - See Arachnoid cysts
* Intracranial arteriovenous malformation
* Intracranial AVM - See Intracranial arteriovenous malformation
* Intracranial hypertension, idiopathic - See Pseudotumor cerebri
* Intractable diarrhea of infancy - See Microvillus inclusion disease
* Intractable hiccups - See Chronic hiccups
* Intractable singultus - See Chronic hiccups
* Intrahepatic cholangiocarcinoma
* Intrahepatic cholestasis of pregnancy
* Intramural diverticulosis of the gallbladder - See Rokitansky-Aschoff sinuses of the gallbladder
* Intraneural perineurioma
* Intraocular melanoma
* Intrathoracic kidney vertebral fusion
* Intrauterine growth retardation - mandibular malar hypoplasia
* Intrauterine growth retardation with increased mitomycin C sensitivity
* Intrauterine growth retardation, short stature, microcephaly, mild mental retardation with behavior problems, eczema, and unusual and distinctive faci - See Dubowitz syndrome
* Intrauterine infections
* Intrauterine synechiae - See Asherman's syndrome
* Intravascular papillary endothelial hyperplasia
* Intravenous leiomyomatosis
* Intrinsic factor deficiency
* Intrinsic factor, congenital deficiency of - See Intrinsic factor deficiency
* Inv dup(15) - See Isodicentric chromosome 15 syndrome
* INV DUP(22)(Q11) - See Cat Eye syndrome
*   Inversion 9 - See Chromosome 9 inversion
* Inverted duplication 15 - See Isodicentric chromosome 15 syndrome
* Inverted smile and occult neuropathic bladder - See Ochoa syndrome
*   Involuntary emotional expression disorder - See Pseudobulbar affect
* Iodine antenatal infection
* IOMID - See Chronic Infantile Neurological Cutaneous Articular syndrome
* IOSCA - See Infantile onset spinocerebellar ataxia
* IP - See Incontinentia pigmenti
* IP2 (formerly) - See Incontinentia pigmenti
* IPA - See Hypomelanosis of Ito
* IPEX syndrome - See Immunodysregulation, polyendocrinopathy and enteropathy X-linked
* IPOX - See Intestinal pseudoobstruction neuronal chronic idiopathic X-linked
* IPS - See Ichthyosis prematurity syndrome
* IRAK4 deficiency - See IRAK-4 deficiency
* IRAK-4 deficiency
* Iraqi Jewish optic atrophy plus - See 3-methylglutaconic aciduria type III
* IRD - See Refsum disease, infantile form
* IRDS - See Respiratory distress syndrome, infant
* IRID1 - See Iridogoniodysgenesis type1
* IRID2 - See Iridogoniodysgenesis, dominant type
* IRIDA - See Iron-refractory iron deficiency anemia
* IRIDA syndrome - See Iron-refractory iron deficiency anemia
* Iridocorneal endothelial syndrome
* Iridocyclitis - See Anterior uveitis
* Iridogoniodysgenesis and skeletal anomalies
* Iridogoniodysgenesis anomaly, Autosomal dominant - See Iridogoniodysgenesis type1
* Iridogoniodysgenesis syndrome - See Iridogoniodysgenesis, dominant type
* Iridogoniodysgenesis type 2 - See Iridogoniodysgenesis, dominant type
* Iridogoniodysgenesis type1
* Iridogoniodysgenesis with somatic anomalies - See Axenfeld-Rieger syndrome
* Iridogoniodysgenesis, dominant type
* Iris coloboma with ptosis hypertelorism and mental retardation - See Trigonocephaly ptosis mental retardation
* Iris coloboma with ptosis hypertelorism and mental retardation - See Baraitser-Winter syndrome
* Iris coloboma, mental retardation, obesity, hypogenitalism, and postaxial polydactyly - See Biemond syndrome 2
* Iris dysplasia - hypertelorism - deafness - See Iris dysplasia hypertelorism deafness
* Iris dysplasia hypertelorism deafness
* Iris hypoplasia and glaucoma
* Iris hypoplasia with early onset glaucoma, autosomal dominant - See Iridogoniodysgenesis, dominant type
* Iron miners lung - See Silicosiderosis
* Iron overload disease juvenile - See Hemochromatosis type 2
* Iron overload in Africa - See Bantu siderosis
* Iron-handling disorder, hereditary - See Iron-refractory iron deficiency anemia
* Iron-refractory iron deficiency anemia
* Irons Bhan syndrome
*   Irritable bowel syndrome
* IS - See West syndrome
* Isaac's syndrome
* Isaac's-Merten's syndrome - See Isaac's syndrome
* ISCH - See Idiopathic spinal cord herniation
* Ischemic optic neuropathy - See Optic neuropathy, anterior ischemic
* Ischiadic hypoplasia renal dysfunction immunodeficiency
* Ischiopatellar dysplasia - See Small patella syndrome
* Islet cell carcinoma - See Pancreatic islet cell tumors
* Islet cell tumors - See Pancreatic islet cell tumors
* Islet of Langerhans tumor - See Pancreatic islet cell tumors
* Isobutyryl-CoA dehydrogenase deficiency
* Isochromosome 18p - See Chromosome 18p tetrasomy
* Isochromosome Yp
* Isodicentric chromosome 15 syndrome
* Isolated 3-methylcrotonyl-CoA carboxylase deficiency - See 3-methylcrotonyl-CoA carboxylase deficiency
* Isolated ACTH deficiency
* Isolated Adrenocorticotropic hormone deficiency - See Isolated ACTH deficiency
* Isolated autosomal dominant polycystic liver disease - See Polycystic liver disease
* Isolated cloverleaf skull syndrome - See Kleeblattschaedel syndrome
* Isolated congenital anosmia - See Congenital anosmia
* Isolated congenital nail dysplasia - See Nail dysplasia, isolated congenital
* Isolated diffuse mesangial sclerosis - See Diffuse mesangial sclerosis
* Isolated ectopia lentis
* Isolated follicle-stimulating hormone (FSH) deficiency - See Follicle-stimulating hormone deficiency, isolated
* Isolated FSH deficiency - See Follicle-stimulating hormone deficiency, isolated
* Isolated growth hormone deficiency type 1A
* Isolated growth hormone deficiency type 1B
* Isolated growth hormone deficiency type 2
* Isolated growth hormone deficiency type 3
* Isolated growth hormone deficiency type II - See Isolated growth hormone deficiency type 2
* Isolated hyperostosis of the calvarium - See Calvarial hyperostosis
* Isolated hypoplasia of the right ventricle - See Right ventricle hypoplasia
* Isolated levocardia
* Isolated levocardia with situs inversus - See Isolated levocardia
* Isolated polycystic liver disease - See Polycystic liver disease
* Isolated right ventricular hypoplasia - See Right ventricle hypoplasia
* Isolated UAPA - See Unilateral absence of a pulmonary artery
* Isolated unilateral absence of a pulmonary artery - See Unilateral absence of a pulmonary artery
* Isosporiasis
* Isotretinoin (RoAccutane) embryopathy - See Fetal retinoid syndrome
* Isotretinoin embryopathy - See Fetal retinoid syndrome
* Isotretinoin embryopathy like syndrome
* Isotretinoin fetal effects of - See Fetal retinoid syndrome
* Isotretinoin teratogen syndrome - See Fetal retinoid syndrome
* Isovaleric acid CoA dehydrogenase deficiency - See Isovaleric acidemia
* Isovaleric acidemia
* Isovaleryl CoA carboxylase deficiency - See Isovaleric acidemia
* ISSD - See Infantile free sialic acid storage disease
* Isthmian coarctation
* ITCH E3 ubiquitin ligase deficiency
* ITO - See Hypomelanosis of Ito
* Ito hypomelanosis - See Hypomelanosis of Ito
* ITP - See Idiopathic thrombocytopenic purpura
* IVA - See Isovaleric acidemia
* IVD deficiency - See Isovaleric acidemia
* Ivemark syndrome
* IVF - See Paroxysmal ventricular fibrillation
* IVIC syndrome
* Iwashita syndrome - See Autosomal recessive optic atrophy, hearing loss, and peripheral neuropathy