Diseases

Heterotaxy- visceral- X-linked

Heterotaxy ('heter' meaning 'other' and 'taxy' meaning 'arrangement'), or situs ambiguus, is a developmental condition characterized by randomization of the placement of visceral organs, including the heart, lungs, liver, spleen, and stomach. The organs are oriented randomly with respect to the left-right axis and with respect to one another (Srivastava, 1997). 30 PubMed Neighbors Heterotaxy is a clinically and genetically heterogeneous disorder. See also HTX2 (605376), caused by mutation in the CFC1 gene (605194) on chromosome 21; HTX3 (606325), which maps to 6q21; and HTX4, caused by mutation in the ACVR2B gene (602730).

HHV-6 encephalitis

A rare condition that usually occurs in immunocompromised people such as those undergoing transplants or HIV patients. The condition causes neurological symptoms.

Hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic skin disease characterized by recurrent, painful, boil-like lumps (nodules) under the skin. HS affects the areas around skin folds (e.g., armpits, groin, and breasts) and where apocrine glands (a form of sweat gland) and hair follicles are found. It is not contagious, but it is recurrent. It typically manifests as a single boil-like, pus-filled abscess or hard sebaceous lumps (lumps composed of sebum, or oil, which is excreted by the sebacous glands associated with hair follicles) and may progress to painful, deep-seated, inflamed clusters of lesions with chronic seepage involving significant scarring. In most cases, the cause of HS is unknown. It is likely that it results from a combination of genetic and environmental factors. Some cases of HS have been associated with specific genes, including NCSTN, PSEN1, and PSENEN. 
Hidradenitis suppurativa tends to start after puberty, persist for years and worsen over time. Early diagnosis and treatment can help manage the symptoms and prevent new lesions from developing.

Hillig syndrome

A very rare syndrome characterized mainly by mental retardation, large head, coarse face and reduced muscle tone.

Hip dislocation

A dislocated hip is a condition that can be congenital or acquired. Congenital hip dislocations are much more common in girls than in boys. Hip dislocations are relatively uncommon during athletic events.1 Injuries to small joints (eg, finger, wrist, ankle, knee) are much more common. However, serious morbidity can be associated with hip dislocations, making careful and expedient diagnosis and treatment important for the sports medicine physician.

Hip Dysplasia

A dislocation of the hip at birth or a hip joint that dislocates easily.

Hip luxation

Hip dislocation - the ball of the hip joint comes out of the socket.

Hip subluxation

Partial dislocation of the hip - the ball of the hip joint is only partially in the socket.

Hipo syndrome

A very rare syndrome characterized mainly by an intestinal web, corneal opacity and excessive growth on one side of the body giving it an asymmetrical appearance.

Hirschsprung disease type 2

A developmental defect of the intestinal tract where the muscles of the intestines are unable to function and move food along the digestive tract. This form of Hirschsprung disease is differentiated from the other types by the location of the genetic defect.

Hirschsprung disease type 3

A developmental defect of the intestinal tract where the muscles of the intestines are unable to function and move food along the digestive tract. This form of Hirschsprung disease is differentiated from the other types by the location of the genetic defect

Hirschsprung disease type d brachydactyly

A developmental defect of the intestinal tract where the muscles of the intestines are unable to function and move food along the digestive tract. This form of Hirschsprung disease also involves finger and toe abnormalities.

Hirschsprung’s disease

Hirschsprung's disease (HD) is a form of megacolon that occurs when part or all of the large intestine or antecedent parts of the gastrointestinal tract have no ganglion cells and therefore cannot function. During normal prenatal development, cells from the neural crest migrate into the large intestine (colon) to form the networks of nerves called the myenteric plexus (Auerbach plexus) (between the smooth muscle layers of the gastrointestinal tract wall) and the submucosal plexus (Meissner plexus) (within the submucosa of the gastrointestinal tract wall). In Hirschsprung's disease, the migration is not complete and part of the colon lacks these nerve bodies that regulate the activity of the colon. The affected segment of the colon cannot relax and pass stool through the colon, creating an obstruction. In most affected people, the disorder affects the part of the colon that is nearest the anus. In rare cases, the lack of nerve bodies involves more of the colon. In five percent of cases, the entire colon is affected. Stomach and esophagus may be affected too.

Hirschsprung's disease occurs in about one in 5,000 of live births. It is usually diagnosed in children, and affects boys more often than girls. About 10% of cases are familial.

His bundle tachycardia

A rare severe type of abnormal heart rhythm that occurs in infants less than 6 months old. Untreated, the condition can lead to heart disease and even death.

Histidinemia

A metabolic disorder where there is a deficiency of the histidase enzyme which is needed to metabolise the amino acid called histidine. Histidine levels then buildup of histidine in the blood and urine.

Histiocytosis X

Histiocytosis is a general name for a group of syndromes that involve an abnormal increase in the number of immune cells called histiocytes. There are three major classes of histiocytoses, namely, Langerhans cell histiocytosis, Malignant histiocytosis syndrome and Non-Langerhans cell histiocytosis.

Histiocytosis- Non-Langerhans-Cell

A group of disorders involving the excessive proliferation of histiocytes (macrophages) which are not Langerhans cells. Subgroups of this disorder includes hemophagocytic lymphohistiocytosis, sinus histiocytosis, xanthogranuloma and sea-blue histiocyte syndrome. Sometimes only the skin is involved and in other cases there may be systemic involvement which can cause serious problems.