Product Code Database
Example Keywords: dungeon master -mmorpg $44-115
barcode-scavenger
   » » Wiki: Aplasia
Tag Wiki 'Aplasia'.
Tag
20%

Aplasia (; from a, "not", "no" + plasis, "formation") is a where an organ or tissue is wholly or largely absent. It is caused by a defect in a developmental process.

(1990). 9780683079166, Williams and Wilkins.

is the failure of the body to produce blood cells. It may occur at any time, and has multiple causes.


Types

Pure red cell aplasia
Pure red cell aplasia (PRCA) is caused by the selective destruction or inhibition of erythroid progenitor or . It is characterized by and reticulocytopenia and can be chronic or acute. Diamond–Blackfan anemia is a type of PRCA that occurs at birth. PRCA can be acquired as a primary disorder or as a result of another disorder. Immunosuppressive drugs, particularly corticosteroids, will usually result in a temporary or permanent remission. The final outcome is primarily determined by the underlying disorder.


Aplasia cutis congenita
Aplasia cutis congenita is a condition in which some or large portions of the skin is missing at birth. The disorder is most commonly seen on the scalp, often as a solitary lesion without other abnormalities. The condition may be caused by epidermolysis bullosa, specific , or intrauterine infections, or it may be caused by chromosomal abnormalities, ectodermal dysplasias, or other malformation syndromes.


Radial aplasia
is a condition in which the does not form. The radius runs from the elbow to the wrist, where the thumb is located. With radial aplasia, the arm can look misshapen and bent. The thumb could also be absent or shorter than usual.


Sertoli cell-only syndrome
Sertoli cell-only syndrome (SCOS), also known as germ cell aplasia, is defined by where the testicular seminiferous tubules are lined solely with . contribute to the formation of the blood-testis barrier and aid in sperm generation. These cells respond to follicle-stimulating hormone, which is secreted by the and aids in . Men often learn they have Sertoli cell-only syndrome between the ages of 20 and 40 when they are checked for and found to produce no sperm. Other signs and symptoms are uncommon, yet in some cases, an underlying cause of SCO syndrome, such as Klinefelter syndrome, may produce other symptoms.

Most cases of SCO syndrome are idiopathic, however, causes may include deletions of genetic material on regions, particularly the azoospermia factor area. Other factors include , previous exposure to radiation therapy, and a history of severe trauma. A testicular confirms the diagnosis of SCO syndrome. Although there is no effective treatment at the moment, assisted reproductive technology may help some men with SCO syndrome reproduce.


Pulmonary aplasia
Pulmonary aplasia is a rare congenital pathology characterized by the unilateral or bilateral absence of lung tissue. It is distinct from pulmonary agenesis, which, while similar, has a short-blind ending in aplasia. Because bilateral pulmonary aplasia is not feasible, it is usually unilateral. It is frequently associated with other congenital abnormalities, primarily cardiovascular, and has been shown to occur with the VACTERL syndrome.


Thymic aplasia
Thymic aplasia is a rare primary immunodeficiency with autosomal or X-linked recessive inheritance, characterized by in the absence of other congenital abnormalities, profound T-cell deficiency, and normal or increased serum levels. Patients present with chronic or recurring infections in infancy, such as , skin, pulmonary, and urinary tract infections, , and failure to thrive.


Optic nerve aplasia
Optic nerve aplasia (ONA) is a congenital anomaly defined as the absence of the , the blood vessels, ganglion cells of the retina, and optic in an otherwise normal eye. Clinically, the condition is characterized by a lack of light perception, an afferent pupillary defect, and a fundus appearance of an absent optic nerve head and retinal vessels, as well as other ocular and nonocular abnormalities. Bilateral ONA has been linked to systemic anomalies, whereas unilateral ONA is seen in otherwise healthy people.


Aplastic anemia
is a bone marrow failure syndrome characterized by peripheral and hypoplasia. Although the is usually normocytic, mild can be seen in conjunction with stress and raised levels. Aplastic anemia patients present with symptoms related to a decrease in hematopoietic cell production in the . The onset is gradual, and the first symptom is frequently or bleeding, though a or may be present at the onset. The following are examples of specific manifestations:

The majority of cases of aplastic anemia are idiopathic, and seeking a possible cause is frequently unproductive.


Epidemiology
Aplasia is a rare condition. and pure red cell aplasia, particularly the acquired form of pure red cell aplasia, are the most common types. Radial aplasia affects about one in every 30,000 newborns. Radial ray deficiencies, such as radial aplasia, are one of the most common congenital arm disabilities. Congenital pure red cell aplasia is uncommon, with an estimated 5 to 7 cases per million births. The acquired form is more prevalent.


See also

Page 1 of 1
1
Post Comment
Font Size...
Font Family...
Font Format...

Page 1 of 1
1

Account

Social:
Pages:  ..   .. 
Items:  .. 

Navigation

General: Atom Feed Atom Feed  .. 
Help:  ..   .. 
Category:  ..   .. 
Media:  ..   .. 
Posts:  ..   ..   .. 

Statistics

Page:  .. 
Summary:  .. 
1 Tags
10/10 Page Rank
5 Page Refs
1s Time