Hermansky-Pudlak syndrome (HPS) is a rare syndrome which consists of:
oculocutaneous hypopigmentation (albinism)
abnormal storage of autofluorescent pigment (ceroid or lipofuscin)
typically occurs within lysosomal organelles of the cells of multiple organs and the reti...
Heterotaxy syndrome or situs ambiguus (also commonly, but etymologically less correctly, spelled situs ambiguous) is a disturbance in the usual left and right distribution of the thoracic and abdominal organs which does not entirely correspond to the complete or partial mirror image.
It occurs ...
Heyde syndrome is an association between aortic valve stenosis and gastrointestinal hemorrhage.
The etiology of the gastrointestinal bleeding in this setting is uncertain, but it is thought to be related to intestinal angiodysplasia. The strength of this association independent of age-related d...
HIV-associated nephropathy (HIVAN) is commonly seen in patients with HIV/AIDS and leads to end-stage renal disease (ESRD). The diagnosis is not imaging-based and must be confirmed by renal biopsy.
HIVAN is seen in patients at advanced stages of HIV and AIDS, but it can also be see...
HGPPS is a rare autosomal recessive AR congenital anomaly caused by mutation of ROBO3 gene on chromosome 11.
Abnormal horizontal gaze while normal vertical gaze and kyphoscoliosis. Horizontal gaze requires the action of ipsilateral abducent nerve and contralateral oculomo...
Hydrolethalus syndrome is a rare lethal genetic syndrome characterized by multiple developmental defects of fetus which include
cleft lip + / - palate
agenesis of the corpus callosum
absent midline stru...
Hyperimmunoglobulin E (hyper IgE) syndrome (HIES), also known as Job syndrome, consists of a heterogeneous group of complex hereditary combined B- and T-cell immune deficiency diseases characterized by recurrent Staph aureus chest infections, characteristic coarse facial appearance and dental pr...
Hyperparathyroidism-jaw tumor syndrome is an extremely rare condition where a gene mutation results in hyperparathyroidism in association with both benign and malignant tumors, most notably, tumors in the mandible or maxilla 2.
Approximately 200 cases have been reported in the med...
Hyperperfusion syndrome after carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare complication.
Hyperperfusion occurs in ~7.5% (range 1-14%) of patients but only a minority (~1.5%) of patients are symptomatic 1,2, with incidence being reported slightly more af...
Hypomelanosis of Ito, also known as incontinentia pigmentiachromians, is the third most frequent phakomatosis, involving a wide spectrum of defects in multiple organ systems.
The prevalence is unknown, being reported since 1 per 8000 patients in a general pediatric hospital 3 to 1...
Hypoplastic left heart syndrome (HLHS) is a cyanotic congenital cardiac anomaly where affected individuals can have profound cyanosis and cardiac failure.
It is one of the commonest causes for a neonate to present with congestive cardiac failure and the 4th most frequent cardiac anomaly to mani...
Hypothenar hammer syndrome occurs from trauma to the distal ulnar artery or proximal portion of superficial palmar arch as a result of repetitive trauma to the hypothenar eminence. Originally described in patients using hammers and screwdrivers, it is also seen in various athletes such as basket...
Idiopathic pneumonia syndrome (IPS) refers to diffuse lung injury which can occur following haematopeotic stem cell transplantation where neither an infectious nor non-infectious etiology can be found.
The incidence of IPS is thought to be around 12% following haematopoetic stem c...
Idiopathic pulmonary fibrosis (IPF) is a clinical syndrome and considered the most common and the most lethal form of pulmonary fibrosis corresponding to the histologic and imaging pattern of UIP. It is more common in middle age or elderly men and diagnosed by:
histological or imaging pattern ...
Iliotibial band (friction) syndrome is a common cause of lateral knee pain related to intense physical activity resulting in chronic inflammation.
Commonly affect young patients who are physically active, most often long distance runners or cyclists. The exact prevalence is unknow...
Immune reconstitution inflammatory syndrome (IRIS) is paradoxical deterioration of a pre-existing illness following abrupt improvement in an individual's immune function. It is classically seen in HIV/AIDS patients following initiation of highly active anti-retroviral therapy (HAART). Increasing...
Incontinentia pigmenti, also known as Bloch-Sulzberger syndrome, is a rare condition that can affect many body systems, specially the skin. As an X-linked dominant genetic disorder, it occurs much more often in females than in males.
Incontinentia pigmenti is rare and the true pre...
Inferior medial pontine syndrome, also known as Foville syndrome, is one of the brainstem stroke syndromes occurring when there is infarction of the medial inferior aspect of the pons due to occlusion of the paramedian branches of the basilar artery 1-3. This infarction involves the following 1-...
Internuclear ophthalmoplegia (INO) describes a clinical syndrome of impaired adduction in one eye with dissociated horizontal nystagmus of the other abducting eye, due to a lesion in the medial longitudinal fasciculus (MLF) ipsilateral to the eye unable to adduct. It is a common finding in multi...
Irritable bowel syndrome (IBS) is the commonest of the functional gastrointestinal disorders (FGIDs). Its key presenting features are recurrent abdominal pain and change in bowel habit (diarrhea and/or constipation), which may be severe, such that for an individual, there may be a marked negativ...
Ischiofemoral impingement refers to the impingement of soft tissues between the ischial tuberosity and lesser trochanter of the femur, primarily the quadratus femoris muscle. Narrowing of the distance between these two osseous landmarks (ischiofemoral space) predisposes for and correlates with i...
Ischiopubic synchondrosis asymmetry (also known as van Neck-Odelberg disease) is characteristic enlargement of one of the ischiopubic synchondroses. It is largely considered an anatomic variant of skeletal developmental, given that it is a common and usually asymptomatic finding.
However, some ...
Jacobsen syndrome (also known as the chromosome 11q deletion syndrome) is a rare chromosomal anomaly that results from deletion of the terminal region of chromosome 11. It results in intellectual disabilities, a distinctive facial appearance and a variety of physical problems including heart def...
Jaffe-Campanacci syndrome is characterized by:
multiple non-ossifying fibromas of the long bones and jaw
café au lait spots
hypogonadism or cryptorchidism
giant cell granuloma of the jaw
The Jarcho-Levin syndrome (JLS) or spondylothoracic dysostosis is a rare autosomal recessive heterogeneous disorder that can occur with variable severity. Previously the condition spondylocostal dysostosis was also considered as part of the JLS spectrum but is now considered a distinct pathologi...
Johanson-Blizzard syndrome is a disorder of ectodermal dysplasia with a wide variability in its manifestations. It is thought to have autosomal recessive inheritance.
There is a wide variability in the clinical presentation, but common features are:
low birth weight
Juberg-Hayward syndrome (JHS), also known as the oro-cranio-digital syndrome, is a rare autosomal recessive syndrome characterized by the association of the following:
cleft lip and palate
minor vertebral and rib anomalies 4
horseshoe kidneys 4
Juvenile polyposis syndrome, also referred as familial juvenile polyposis, is one of the polyposis syndromes and consists of hundreds of juvenile polyps.
Presentation in the second decade is most common 2.
Rectal bleeding, bowel obstruction and intussuscept...
Kabuki syndrome (Niikawa-Kuroki syndrome) is a rare polydysplasia that is thought to be more common in Japan.
Estimated incidence of 1:32,000 in Japan. Sporadically seen elsewhere in the world. The reason for the disparity in incidence is controversial.
The cause for t...
Kartagener syndrome is a subset of primary ciliary dyskinesia, an autosomal recessive condition characterized by an abnormal ciliary structure or function, leading to impaired mucociliary clearance.
The prevalence of primary ciliary dyskinesia is approximately 1 in 12,000-60,000 ...
Kasabach-Merritt syndrome, also known as hemangioma thrombocytopenia syndrome, is a rare life-threatening disease found in infants in which a rapidly growing vascular tumor is responsible for thrombocytopenia, microangiopathic hemolytic anemia and consumptive coagulopathy.
Klinefelter syndrome (KS) is a chromosomal anomaly, which in most cases is characterized by 47 chromosomes instead of the usual 46.
The estimated incidence is 0.15-0.2% of live births.
the testes are normal prior to puberty and small in post pubertal testes...
Klippel-Feil syndrome is a complex heterogeneous entity that results in cervical vertebral fusion. Two or more non-segmented cervical vertebrae are usually sufficient for diagnosis.
There is a recognised female predilection 1. Klippel-Feil syndrome has an incidence of 1:40,000-42,...
Klippel-Trénaunay-Weber syndrome (KTWS) is a syndrome combination of capillary malformations, soft-tissue or bone hypertrophy, and varicose veins or venous malformations. It is considered an angio-osteo-hypertrophic syndrome.
KTS classically comprises a triad of:
port wine nevi
bony or soft t...
Kyphomelic dysplasias (also known as "pseudocampomelia") is thought to be a heterogeneous class of "bent bone" skeletal dysplasias. Entities included in a differential for the class are:
congenital bowing of the long bones
cartilage-hair hypoplasia (CHH; metaphyseal dysplasia, McKusick type)
Lacunar stroke syndrome (LACS) is a description of the clinical syndrome that results from a lacunar infarct.
Each of the five classical lacunar syndromes has a relatively distinct symptom complex. Symptoms may occur suddenly, progressively, or in a fluctuating manner (e.g. the capsular warnin...
Lambert-Eaton myasthenic syndrome (LEMS) is a rare neuromuscular junction disorder of paraneoplastic or primary autoimmune etiology.
LEMS is the second most common neuromuscular junction disease after myasthenia gravis.
Two-thirds of LEMS present as a paraneoplastic syndrome sec...
Lane-Hamilton syndrome (LHS) refers to the rare concurrent association of idiopathic pulmonary hemosiderosis and celiac disease 1.
It is typically seen in children under the age of 15 but can occasionally be seen in adults.
History and etymology
It was originally described by D ...
Langer-Giedion syndrome, also known as trichorhinophalangeal syndrome type II, is an extremely rare autosomal dominant genetic disorder.
The effects are seen mainly on the skeletal system and primarily involves
digits of the hands and feet: phalangeal
Large vestibular aqueduct syndrome, also known as large endolymphatic sac anomaly, refers to the presence of congenital sensorineural hearing loss with an enlarged vestibular aqueduct. It is thought to be one of the most common congenital causes of sensorineural hearing loss.
Larsen syndrome (LS) is an extremely rare disorder, often classified as a type of osteochondrodysplasia.
The estimated incidence is thought to be at ~ 1 in 100,000 people. There may be an increased female predilection.
It is characterized by many features i...
Lateral medullary syndrome (or Wallenberg syndrome) is a clinical syndrome caused by an acute ischemic infarct of the lateral medulla oblongata. This is most commonly due to occlusion of the intracranial portion of the vertebral artery followed by PICA and its branches 1-3. This syndrome is cha...
Lateral meningocele syndrome is an extremely rare hereditary connective tissue disorder characterized by multiple lateral lumbar meningoceles, distinctive facial features, joint hypermobility, hypotonia, skeletal abnormalities, congenital cardiovascular malformations, urogenital anomalies and ne...
Lateral pontine syndrome, also known as Marie-Foix syndrome or Marie-Foix-Alajouanine syndrome, refers to one of the brainstem stroke syndromes of the lateral aspect of the pons.
There is a characteristic clinical picture from the involvement of the following pontine stru...
Laurin-Sandrow syndrome is a rare disorder characterized by tetrameric polysyndactlyly.
polysyndactyly of the hands (both post-axial and pre-axial)
mirror polysyndactyly of the feet
absence of the radius and tibia
Leaky lung syndrome refers to a form of non-cardiogenic pulmonary edema.
Pulmonary edema due to increased capillary permeability.
Leaky lung syndrome is considered a mild form of a part of the spectrum of acute lung injury with ARDS at the other end of the s...
Lemierre syndrome refers to thrombophlebitis of the jugular veins with distant metastatic sepsis in the setting of initial oropharyngeal infection such as pharyngitis/tonsillitis with or without peritonsillar or retropharyngeal abscess.
Since the advent of antibiotics, the inciden...
Lemmel syndrome is defined as an obstructive jaundice caused by a periampullary duodenal diverticulum (of the second part of the duodenum) compressing the intrapancreatic part of the common bile duct with resultant upstream dilatation of the extra- and intrahepatic bile ducts.
Leontiasis ossea is largely a historical term used to describe a number of conditions that result in the affected patient's face resembling that of a lion. Although it is most frequently associated with craniofacial fibrous dysplasia, it has a broader meaning encompassing other lesions that have...
Leprosy, previously known as Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae and presents mainly in tropical developing countries.
It is most common in tropical developing countries and is endemic in over 100 countries. Worldwide, there is a preval...
Lethal omphalocele-cleft palate syndrome is, as the name suggests, characterized by the association of omphalocele and cleft palate.
Prevalence is assumed to be <1 per 1,000,000. It has been postulated that this syndrome is likely to be an autosomal recessive condition 1.
History and etymolog...
Leukoencephalopathy with calcifications and cysts, also known as Labrune syndrome, is a rare condition that consists of a triad of leukoencephalopathy, cerebral calcifications and edematous cysts.
Leukoencephalopathy with calcifications and cysts is an extremely rare condition, wi...
Levator ani syndrome (LAS) is a musculoskeletal pain syndrome involving the pelvic floor, thought to be caused by spasm or scarring of the levator ani muscles.
Levator ani syndrome is characterized by recurrent pain, pressure or discomfort in the region of the rectum, sac...
Li-Fraumeni syndrome is a hereditary cancer syndrome due to mutations in the tumor suppressor gene TP53. Approximately half of affected individuals are thought to develop invasive cancer by 30 years of age 1.
Locked-in syndrome is a condition that can occur as a result of a stroke involving the brainstem; the stroke damages the ventral brainstem, corresponding to the pyramidal bundles.
The infarct is pontine; the midbrain is preserved. The oculomotor nerve III is intact so the...
Simple pulmonary eosinophilia (also known as Löffler syndrome) is a type of pulmonary eosinophilia that typically presents with transient radiographic infiltrates, minimal constitutional upset, and an elevated eosinophil count in peripheral blood.
The cause is not usually i...
Löfgren syndrome is a specific acute clinical presentation of systemic sarcoidosis that usually manifests with lymphadenopathy, fevers, erythema nodosum, and arthritis.
It is important to not confuse this syndrome with Löffler syndrome, as the names are quite similar but the condi...
Lowe syndrome (also known as the the oculocerebrorenal syndrome of Lowe) is a multi-system disorder characterized by anomalies primarily affecting the eyes, nervous system, and kidneys.
It is an extremely rare, pan-ethnic, x-linked disease, with estimated prevalence in the general po...
Low phospholipid-associated cholelithiasis (LPAC) syndrome is one of the syndromes associated with ABCB4/MDR3 mutation. Characteristics of this syndrome include 1,2:
symptomatic cholesterol stones with early onset (<40 years)
recurrent symptoms post cholecys...
Lutembacher syndrome refers to the association of an atrial septal defect (ASD) with mitral stenosis. Both the defects can be either congenital or acquired.
History and etymology
It is named after Rene Lutembacher 4.
Madelung disease, also known as Madelung-Launois-Bensaude syndrome or neck lipomatosis or multiple symmetric lipomatosis, is a rare benign entity clinically characterized by the presence of multiple and symmetric, non-encapsulated masses of fatty tissue, usually involving the neck and the upper ...
Maffucci syndrome is a congenital nonhereditary mesodermal dysplasia characterized by multiple enchondromas with soft-tissue venous malformations (hemangiomas).
On imaging, it is usually portrayed by a short limb with metaphyseal distortions due to multiple enchondromas, which may appear grotes...
Mainzer-Saldino syndrome (also known as conorenal syndrome (CRS)) is a rare condition and is one of the ciliopathies. It is due to mutations in the IFT140 gene, whose protein product is one of the six parts of the intraflagellar transport complex A.
The syndrome's key characteristics are:
Man-in-the-barrel syndrome is a neurological syndrome characterized by bilateral brachial muscular weakness.
This syndrome is usually caused by bilateral cerebral lesions in the border zone between the anterior and middle cerebral arteries.
The syndrome has been described ...
Marchiafava-Bignami disease (MBD) is a rare CNS disorder usually seen in the context of alcoholism and malnutrition. The condition classically involves the corpus callosum with necrosis and demyelination.
MBD is in most instances seen in chronic alcoholics, and as such the epidem...
Marfan syndrome is a multisystem connective tissue disease caused by a defect in the fibrillin 1 gene. Cardiovascular involvement with aortic root dilatation and dissection is the most feared complication of the disease.
The estimated prevalence is around 2-6 per 100,000 2,5. Ther...
Marine-Lenhart syndrome refers to a variant of Graves disease where there are coexistent autonomous thyroid nodules. It is better described as Graves disease with coexistent multinodular goiter or nodular Graves disease 1.
The syndrome is rare with reported prevalence somewhere b...
Marshall-Smith syndrome (MSS) is a rare genetic syndrome primarily comprising of the triad of facial dysmorphism, failure to thrive and accelerated osseous maturation 5. Many cases, however, have a wider clinical spectrum.
failure to thrive
May-Thurner syndrome refers to a chronic compression of the left common iliac vein (CIV) against the lumbar vertebrae by the overlying right common iliac artery (CIA), with or without deep venous thrombosis 2.
Although both left and right CIVs lie deep to the right common iliac artery, the left...
Mazabraud syndrome is a rare syndrome consisting of:
fibrous dysplasia: usually polyostotic 2
multiple soft tissue myxomas (intramuscular myxomas): typically in large muscle groups
It is very rare, with only 81 cases in the global literature reported to 2012 13. It is most frequ...
McCune-Albright syndrome (MAS) is a genetic disorder characterized by the association of:
endocrinopathy: precocious puberty
polyostotic fibrous dysplasia: more severe than in sporadic cases
cutaneous pigmentation: coast of Maine 'cafe au lait' spots
Presentation is va...
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterized by
hydrometrocolpos - vaginal atresia
congenital heart disease
Meckel-Gruber syndrome (MGS) is classically characterized by the triad of:
renal cystic dysplasia: multiple renal cysts (present most cases)
occipital encephalocoele / holoprosencephaly (~70%)
postaxial polydactyly: usually hexadactyly (~65%)
Additional hepatic developmental defects and hepa...
Meconium plug syndrome refers to a functional colonic obstruction in a newborn due to an obstructing meconium plug. It is usually transient and affects the left colon with meconium plugging the bowel distal to this segment. In this situation, it is also termed the small left colon syndrome.
Medial medullary syndrome, also known as Déjerine syndrome, represents less than 1% of brainstem stroke syndromes 1,2. Thrombotic or embolic occlusion of small perforating branches from vertebral or proximal basilar artery supplying the medial aspect of medulla oblongata cause this rare syndrome...
Medial patellar plica syndrome is one of the conditions that can be associated with the presence of synovial plicae of the knee (in this instance a medial plica). It can be a common source of anterior knee pain.
While it can affect those of any age, it typically involves the young...
Medial tibial stress syndrome (MTSS), also known as shin splints, describes a spectrum of stress injury that occurs at the medial tibia. This term is often used to indicate any type of tibial stress injury or the earlier manifestations of a tibial stress lesion before a fracture component can be...
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) (also known as the Berdon syndrome) is a rare congenital disorder characterized by a dilated non-obstructive urinary bladder and hypoperistalsis of the gastrointestinal tract.
There is recognised strong female predi...
Megalencephaly-capillary malformation (MCAP) syndrome, also known as macrocephaly-capillary malformation syndrome, is a rare and well described genetic disorder caused by somatic mutations in the PIK3CA gene on chromosome 3q26 and characterized by early brain overgrowth and body morphogenesis an...
Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia.
The etiologic agents is believed to be aspiration of acidic stomach contents, other compounds, e.g. bile, may also play a rol...
Menkes disease, also known as trichopoliodystrophy or kinky hair kinky vessel syndrome, is an X-linked recessive disorder that results in a derangement in copper handling. It results in low copper levels and subsequently, deficiency in copper-dependent mitochondrial enzymes.
The metabolic syndrome, also known as syndrome X, is a set of five conditions, which together increase a patient's risk of developing cardiovascular disease 1.
There are five central components of the metabolic syndrome:
impaired glucose tolerance
Metaphyseal chondrodysplasia (also known as metaphyseal dysplasia or dysostosis) is a type of skeletal dysplasia.
Schmid type - mild type, due to mutation in type X collagen (COL10A1 gene), metaphyses are cupped resembling rickets
Pena and Vaandrager type - intermedi...
Metronidazole, which is used to treat a wide variety of bacterial and protozoal infections can, in exceedingly rare cases, lead to central nervous system toxicity.
In a review of the case literature 1, affected patients range widely in age, with the peak incidence occurring in the...
Midaortic syndrome is an uncommon entity affecting children and young adults. It is characterized by progressive narrowing of the abdominal aorta and its major branches.
The onset of symptoms is usually during childhood or young adulthood 2:
hypertension (most common)
Middle East Respiratory Syndrome coronavirus (MERS-CoV) infection is an uncommon viral infection (<1000 cases) with the first case reported in Saudi Arabia in 2012. It most commonly causes pneumonia and acute renal failure with a mortality rate of ~40%. MERS-CoV raises concern because of its sim...
Mikulicz syndrome was considered a form of Sjögren syndrome (type 1), however, more recently it is considered in IgG4 related disease spectrum.
It may also be referred to by numerous other eponymous names as well as the catchy: sicca syndrome without a connective tissue disorder 3...
Milk-alkali syndrome is the combination of:
It is due to the large amounts of calcium and alkali being ingested (e.g. milk and antacids for peptic ulcer disease treatment or calcium carbonate for osteoporosis). It is a cause of medullary nephro...
Millard-Gubler syndrome, also known as ventral pontine syndrome, is one of the crossed paralysis syndromes, which are characterized by cranial nerves VI and VII palsies with contralateral body motor or sensory disturbances 1-3.
ipsilateral facial and contralateral body he...
Milwaukee shoulder refers to a destructive shoulder arthropathy due to deposition of hydroxyapatite crystals, and identification of these crystals in synovial fluid is the cornerstone of diagnosis.
Milwaukee shoulder frequently affects older women, often with a history of trauma t...
The Mirizzi syndrome refers to an uncommon phenomenon which results in extrinsic compression of an extrahepatic biliary duct from one or more calculi within the cystic duct or gallbladder. It is a functional hepatic syndrome but can often present with biliary duct dilatation and can mimic other ...
Möbius syndrome, also known as congenital facial diplegia syndrome, is a rare congenital condition characterized by the absence or underdevelopment of the abducens nerve (CN VI) and facial nerve (CN VII) nuclei.
Möbius syndrome is rare with an estimated incidence of ~1 case per 10...
Morgagni-Stewart-Morel syndrome consists of the triad of:
hyperostosis frontalis interna
excessive hair growth (virilism/hirsutism)
and is also associated with neuropsychiatric conditions. The cause is unclear.
History and etymology
It was first described in 1765 by the Italian ...