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

• Rabies
• Rabson–Mendenhall syndrome
• Radial defect Robin sequence
• Radial hypoplasia, triphalangeal thumbs and hypospadias
• Radial ray agenesis
• Radial ray hypoplasia choanal atresia
• Radiation induced angiosarcoma of the breast
• Radiation induced meningioma
• Radiation leukemia
• Radiation related neoplasm /cancer
• Radiation syndromes
• Radiation-induced brachial plexopathy
• Radiation-induced lumbosacral plexopathy
• Radiculomegaly of canine teeth congenital cataract
• Radio digito facial dysplasia
• Radio renal syndrome
• Radiophobia
• Radioulnar synostosis mental retardation hypotonia
• Radioulnar synostosis retinal pigment abnormalities
• Radio-ulnar synostosis type 1
• Radio-ulnar synostosis type 2
• Radius absent anogenital anomalies
• Raine syndrome

• Rambam Hasharon syndrome
• Rambaud–Galian syndrome
• Ramer–Ladda syndrome
• Ramon syndrome
• Ramos-Arroyo syndrome
• Ramsay Hunt paralysis syndrome
• Rapadilino syndrome
• Rapp–Hodgkin syndrome
• Rapunzel syndrome
• Rasmussen's encephalitis
• Rasmussen–Johnsen–Thomsen syndrome
• Rasmussen subacute encephalitis
• Ray–Peterson–Scott syndrome
• Raynaud's disease/phenomenon
• Rayner–Lampert–Rennert syndrome

• Reactive airway disease
• Reactive arthritis
• Reactive attachment disorder (RAD)

• Reactive attachment disorder of early childhood
• Reactive attachment disorder of infancy

• Reactive hypoglycemia
• Reardon–Hall–Slaney syndrome
• Reardon–Wilson–Cavanagh syndrome
• Rectal neoplasm
• Rectophobia
• Rectosigmoid neoplasm
• Recurrent laryngeal papillomas
• Recurrent peripheral facial palsy
• Recurrent respiratory papillomatosis
• Reductional transverse limb defects
• Reflex sympathetic dystrophy syndrome
• Reflux esophagitis
• Refractory anemia
• Refsum disease, infantile form
• Refsum disease
• Reginato–Shiapachasse syndrome
• Regional enteritis

• Reifenstein syndrome
• Reinhardt–Pfeiffer syndrome

• Renal adysplasia dominant type
• Renal agenesis meningomyelocele Müllerian defect
• Renal agenesis, bilateral
• Renal agenesis
• Renal artery stenosis
• Renal calculi
• Renal caliceal diverticuli deafness
• Renal cancer
• Renal carcinoma, familial
• Renal cell carcinoma
• Renal dysplasia diffuse autosomal recessive
• Renal dysplasia diffuse cystic
• Renal dysplasia limb defects
• Renal dysplasia megalocystis sirenomelia
• Renal dysplasia mesomelia radiohumeral fusion
• Renal failure
• Renal genital middle ear anomalies
• Renal glycosuria

• Renal hepatic pancreatic dysplasia Dandy Walker cyst
• Renal hypoplasia
• Renal hypertension
• Renal osteodystrophy
• Renal rickets
• Renal tubular acidosis progressive nerve deafness
• Renal tubular acidosis, distal, autosomal dominant
• Renal tubular acidosis, distal, autosomal recessive
• Renal tubular acidosis, distal, type 3
• Renal tubular acidosis, distal, type 4
• Renal tubular acidosis, distal
• Renal tubular acidosis
• Renal tubular transport disorders inborn

• Renier–Gabreels–Jasper syndrome
• Renoanogenital syndrome
• Renoprival hypertension

• Reperfusion injury
• Repetitive strain injury (RSI)
• Resistance to LH (luteinizing hormone)
• Resistance to thyroid stimulating hormone
• Respiratory acidosis
• Respiratory chain deficiency malformations
• Respiratory distress syndrome, adult
• Respiratory distress syndrome, infant
• Restless legs syndrome

• Reticuloendotheliosis
• Retina disorder
• Retinal degeneration
• Retinal dysplasia X linked
• Retinal telangiectasia hypogammaglobulinemia
• Retinitis pigmentosa

• Retinitis pigmentosa-deafness
• Retinis pigmentosa deafness hypogenitalism
• Retinitis pigmentosa mental retardation deafness

• Retinoblastoma
• Retinohepatoendocrinologic syndrome
• Retinopathy anemia CNS anomalies
• Retinopathy aplastic anemia neurological abnormalities
• Retinopathy pigmentary mental retardation
• Retinopathy, arteriosclerotic
• Retinopathy, diabetic
• Retinoschisis

• Retinoschisis, juvenile
• Retinoschisis, X-linked

• Retrograde amnesia
• Retrolental fibroplasia
• Retroperitoneal fibrosis
• Retroperitoneal liposarcoma

• Rett like syndrome
• Rett syndrome

• Revesz syndrome
• Reye's syndrome
• Reynolds–Neri–Hermann syndrome
• Reynolds syndrome

• Rh disease
• Rhabditida infections
• Rhabdoid tumor
• Rhabdomyolysis
• Rhabdomyomatous dysplasia cardiopathy genital anomalies
• Rhabdomyosarcoma

• Rhabdomyosarcoma 1
• Rhabdomyosarcoma 2
• Rhabdomyosarcoma, alveolar
• Rhabdomyosarcoma, embryonal

• Rheumatic fever
• Rheumatism
• Rheumatoid arthritis
• Rheumatoid purpura
• Rheumatoid vasculitis
• Rhinotillexomania
• Rhizomelic dysplasia type Patterson–Lowry
• Rhizomelic pseudopolyarthritis
• Rhizomelic syndrome
• Rhypophobia
• Rhytiphobia

• Ribbing disease
• Richards–Rundle syndrome
• Richieri–Costa–Colletto–Otto syndrome
• Richieri–Costa–Da Silva syndrome
• Richieri–Costa–Gorlin syndrome
• Richieri–Costa–Guion–Almeida syndrome

• Richieri–Costa–Guion–Almeida acrofacial dysostosis
• Richieri–Costa–Guion–Almeida–Cohen syndrome
• Richieri–Costa–Guion–Almeida dwarfism
• Richieri–Costa–Guion–Almeida–Rodini syndrome

• Richieri–Costa–Montagnoli syndrome
• Richieri–Costa–Orquizas syndrome
• Richieri–Costa–Silveira–Pereira syndrome
• Richter syndrome
• Rickets
• Rickettsial disease
• Rickettsialpox
• Rickettsiosis
• Rieger syndrome
• Rift Valley fever
• Right atrium familial dilatation
• Right ventricle hypoplasia
• Rigid mask like face deafness polydactyly
• Rigid spine syndrome

• Riley–Day syndrome
• Ringed hair disease
• Ringworm
• Rivera–Perez–Salas syndrome

• Roberts syndrome
• Robin sequence and oligodactyly
• Robinow–Sorauf syndrome
• Robinow syndrome
• Robinson–Miller–Bensimon syndrome
• Roch–Leri mesosomatous lipomatosis
• Rocky Mountain spotted fever
• Rod monochromacy
• Rod myopathy
• Rodini–Richieri–Costa syndrome
• Rokitansky–Kuster–Hauser syndrome
• Rokitansky sequence
• Romano–Ward syndrome
• Romberg hemi-facial atrophy
• Rombo syndrome
• Rommen–Mueller–Sybert syndrome
• Rosai–Dorfman disease
• Rosenberg–Chutorian syndrome
• Rosenberg–Lohr syndrome
• Roseola infantum
• Rothmund–Thomson syndrome
• Rotor syndrome
• Roussy–Levy hereditary areflexic dystasia
• Rowley–Rosenberg syndrome
• Roy–Maroteaux–Kremp syndrome
• Rozin–Hertz–Goodman syndrome

• Rubella virus antenatal infection
• Rubella, congenital
• Rubella
• Rubeola
• Rubinstein–Taybi like syndrome
• Rubinstein–Taybi syndrome ( gene promoter involvement)
• Rudd Klimek syndrome
• Rudiger syndrome
• Rumination syndrome
• Rupophobia
• Rutledge–Friedman Harrod syndrome
• Ruvalcaba–Churesigaew–Myhre syndrome
• Ruvalcaba syndrome
• Ruvalcaba–Myhre syndrome
• Ruvalcaba–Myhre–Smith syndrome (BRR)
• Ruzicka Goerz Anton syndrome