A defect in the top part of the aorta (aortic arch) that consists of several arterial branches. There is a variety of defects that can occur and symptoms will be determined by the particular defect involved. Possible types of defects includes aortic coarctation and aortic arch hypoplasia.
A rare inherited birth defect where the heart blood vessel called the aorta has a narrowed area which affects blood flow. It is in the area where the ductus arteriosus (ligamentum arteriosum after regression) inserts. The word "coarctation" means narrowing. Coarctations are most common where the aorta—the major artery leading away from the heart—arches toward the abdomen and legs (the aortic arch). The arch may be small in babies with coarctations. Other heart defects may also occur when coarctation is present, typically occurring on the left side of the heart. When a patient has a coarctation, the left ventricle has to work harder. Since the aorta is narrowed, the left ventricle must generate a much higher pressure than normal in order to force enough blood through the aorta to deliver blood to the lower part of the body. If the narrowing is severe enough, the left ventricle may not be strong enough to push blood through the coarctation, thus resulting in lack of blood to the lower half of the body. Physiologically its complete form is manifested as interrupted aortic arch. The degree of constriction is variable which mild cases asymptomatic until adulthood. The poor blood flow to the lower body gives results in it appearing less developed than that upper body.
A rare familial syndrome characterized by the association of aortic dissection and multiple lentigines (brown skin spots). The aorta can rupture in some cases and result in sudden death.
Aortic valve stenosis (or aortic stenosis) occurs when the heart's aortic valve narrows. This narrowing prevents the valve from opening fully, which obstructs blood flow from your heart into your aorta and onward to the rest of your body.
When the aortic valve is obstructed, your heart needs to work harder to pump blood to your body. Eventually, this extra work limits the amount of blood it can pump and may weaken your heart muscle.
Aortic valve stenosis of the child: A birth defect where the aortic valve is abnormally narrow or unable to fully open.
The aortic window is a normally radiolucent region below the aortic arch. It is formed by the bifurcation of the trachea and traversed by the left pulmonary artery. It is visible in the left anterior oblique radiograph of the heart and great vessels. It can play a role in the identification of enlarged lymph nodes. Its borders are the left atrium, vertebral column, and aortic arch.
Apert syndrome is a genetic disorder characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. In addition, a varied number of fingers and toes are fused together (syndactyly). It is classified as a branchial arch syndrome and specifically affects the first branchial (or pharyngeal) arch, which is the precursor of the maxilla and mandible. Since the branchial arches are important developmental features in a growing fetus, disturbances in its development create lasting and widespread effects.
Many of the characteristic facial features of Apert syndrome result from the premature fusion of the skull bones. The head is unable to grow normally, which leads to a sunken appearance in the middle of the face, bulging and wide-set eyes, a beaked nose, and an underdeveloped upper jaw leading to crowded teeth and other dental problems. Shallow eye sockets can cause vision problems. Early fusion of the skull bones also affects the development of the brain, which can disrupt intellectual development. Cognitive abilities in people with Apert syndrome range from normal to mild or moderate intellectual disability.
Individuals with Apert syndrome have webbed or fused fingers and toes. The severity of the fusion varies; at a minimum, three digits on each hand and foot are fused together. In the most severe cases, all of the fingers and toes are fused. Less commonly, people with this condition may have extra fingers or toes (polydactyly). Additional signs and symptoms of Apert syndrome can include hearing loss, unusually heavy sweating (hyperhidrosis), oily skin with severe acne, patches of missing hair in the eyebrows, fusion of spinal bones in the neck (cervical vertebrae), and recurrent ear infections that may be associated with an opening in the roof of the mouth (a cleft palate).
Congenital primary aphakia (CPA) is a rare eye condition that is present at birth in which the lens is missing. In some cases, CPA can be associated with other eye abnormalities including microphthalmia, absence of the iris, anterior segment aplasia, and/or sclerocornea (when the cornea blends with the sclera). This condition is thought to result from an abnormality during the 4th or 5th week of fetal development, which prevents the formation of any lens structure in the eye.
A very rare syndrome characterized by the absence of one or more bones of the fingers and toes, a small head and fusion of fingers.
Aphthous stomatitis is a common condition characterized by the repeated formation of benign and non-contagious mouth ulcers(aphthae) , usually inside the lips, on the cheeks, or on the tongue, in otherwise healthy individuals. The informal term canker sores is also used, mainly in North America, although this may also refer to any mouth ulcer.
The cause is not completely understood, but involves a T cell-mediated immune response triggered by a variety of factors. Different individuals have different triggers, which may include nutritional deficiencies, local trauma, stress, hormonal influences, allergies, genetic predisposition or other factors.
These ulcers occur periodically and heal completely between attacks. In the majority of cases, the individual ulcers last about 7–10 days, and ulceration episodes occur 3–6 times per year. Most appear on the non-keratinizing epithelial surfaces in the mouth (i.e. anywhere except theattached gingiva, the hard palate and the dorsum of the tongue), although the more severe forms, which are less common, may also involve keratinizing epithelial surfaces. Symptoms range from a minor nuisance to interfering with eating and drinking. The severe forms may be debilitating, even causing weight loss due to malnutrition.
The condition is very common, affecting about 20% of the general population to some degree. The onset is often during childhood or adolescence, and the condition usually lasts for several years before gradually disappearing. There is no cure, and treatments aim to manage pain, reduce healing time and reduce the frequency of episodes of ulceration.
Aplasia cutis congenita is a condition in which there is congenital (present from birth) absence of skin, with or without the absence of underlying structures such as bone. It most commonly affects the scalp, but any location of the body can be affected. While most people with aplasia cutis congenita have no other abnormalities, some people have congenital malformations involving the cardiovascular (heart), gastrointestinal, genitourinary, and central nervous systems.
It can be associated with Johanson-Blizzard syndrome, Adams-Oliver syndrome, trisomy 13, and Wolf-Hirschhorn syndrome. It can also seen with exposure to methimazole and carbimazole in utero. This dermatological manifestation has been linked to Peptidase D haploinsufficiency and a deletion in Chromosome 19.
Aplasia cutis congenital - intestinal lymphangiectasia: A rare disorder characterized by a skin defect and dilated intestinal lymph vessels.
A very rare syndrome characterized by a skin defect (localized absence of skin at birth) and nearsightedness and other eye anomalies. Aplasia cutis congenita, high myopia, and cone-rod dysfunction in two sibs: A new autosomal recessive disorder.
A rare syndrome characterized by the underdevelopment or absence of the pelvis, thigh bone, shin bone and ulna (forearm bone) as well as digital and nail abnormalities.
Aplastic anemia is failure of the bone marrow to produce enough blood cells- it's empty (aplastic) or contains very few blood cells (hypoplastic). All blood cell types are affected in this condition: red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia). Aplastic refers to inability of the stem cells to generate mature blood cells. It can be caused by injury to blood stem cells due to exposure to certain drugs, chemotherapy, congenital disorders, drug therapy to suppress the immune system, pregnancy, radiation therapy, or toxins such as benzene or arsenic. When the cause is unknown, it is referred to as idiopathic aplastic anemia. In about half of all cases, no cause can be found. The condition can be acute or chronic.
Low plasma HDL cholesterol that tends to run in families.
A rare inherited condition where a deficiency of apolipoprotein C-II impairs lipoprotein metabolism and results in a build up of chylomicrons and VLDL.
Apparent mineralocorticoid excess (AME/AME1) is a form of inherited high blood pressure/ hypokalemia (abnormally low levels of potassium)or an autosomal recessive disorder that starts during early childhood. The condition results from a genetic defect which causes impaired metabolism of cortisol. The condition responds to glucocorticoid treatment.
Other conditions such as Liddle's Syndrome can mimic the clinical features of AME, so diagnosis can be made by calculating the ratio of free urinary cortisol to free urinary cortisone. Since AME patients create less cortisone, the ratio will much be higher than non-affected patients. Alternatively, one could differentiate between the two syndromes by administering a potassium-sparing diuretic. Patients with Liddle's syndrome will only respond to a diuretic that binds the ENaC channel, whereas those with AME will respond to a diuretic that binds to ENaC or the mineralcorticoid receptor.
AME is exceedingly rare, with less than 100 cases recorded worldwide. Liquorice consumption may also cause a temporary form of AME due to its ability to block 11β-hydroxysteroid dehydrogenase type 2, in turn causing increased levels of cortisol. Cessation of licorice consumption will reverse this form of AME.
Apraxia is a motor disorder caused by damage to the brain (specifically the Anterior parietal cortex), in which someone has difficulty with the motor planning to perform tasks or movements when asked, provided that the request or command is understood and he/she is willing to perform the task. A person with apraxia cannot move his or her lips or tongue to the right place to say sounds correctly because, even though the muscles are not weak, the message from the brain to the mouth are disrupted. The nature of the brain damage determines the severity. Apraxia is an acquired disorder of motor planning, but is not caused by incoordination, sensory loss, or failure to comprehend simple commands (which can be tested by asking the person to recognize the correct movement from a series). It is caused by damage to specific areas of the cerebrum. Apraxia should not be confused with ataxia, a lack of coordination of movements; aphasia, an inability to produce and/or comprehend language; abulia, the lack of desire to carry out an action; or allochiria, in which patients perceive stimuli to one side of the body as occurring on the other. Developmental coordination disorder is the developmental disorder of motor planning.
Oculomotor apraxia Cogan type also called COMA is a very rare inherited eye condition characterized by a defect in side-to-side (horizontal) eye movements. When affected infants rotate their heads to the side to look at an object, their eyes will lag and then move in the opposite direction. To compensate for this, these infants will sharply jerk their heads past the desired object in effort to bring the eyes to a position where they can view the object. This condition can also be associated with mild developmental delay and speech difficulties. Symptoms usually improve throughout the first and second decades of life. The specific cause and inheritance pattern is unknown. Around 50 cases have been described in the medical literature.
Apudoma (medical condition): An endocrine tumor arising from APUD (amine precursor uptake and decarboxylation) cells. Often occurs in the pancreas, prostate and ampulla of Vater. They are derived from neural crest cells. As the tumor can arise in a variety of parts of the body, the symptoms will depend on the location of the tumor and the amount and type of hormone secreted e.g. insulinoma, gastrinoma. The term dates back to at least 1975. Because the label "Apudoma" is very general, it is preferred to use a more specific term when possible.
Aquagenic pruritus is a condition in which contact with water of any temperature causes intense itching without any visible skin changes. The symptoms may begin immediately after contact with water and can last for an hour or more.
A very rare disorder where there is a buildup of cerebrospinal fluid inside the skull due to a narrow canal that connects the third and fourth ventricles of the brain. Blockage of the aqueduct can lead tohydrocephalus, specifically as a common cause of congenital and/or obstructive hydrocephalus. Also referred to as: Hydrocephalus due to congenital stenosis of aquaduct of Sylvius.
The aqueduct of Sylvius is the channel which connects the third ventricle to the fourth ventricle and is the narrowest part of the CSF pathway with a mean cross-sectional area of 0.5 mm2 in children and 0.8 mm2 in adults. Because of its small size, the aqueduct is the most likely place for a blockage of CSF in the ventricular system. This blockage causes ventricle volume to increase because the CSF cannot flow out of the ventricles and cannot be effectively absorbed by the surrounding tissue of the ventricles. Increased volume of the ventricles will result in higher pressure within the ventricles, and cause higher pressure in the cortex from it being pushed into the skull. A person may have aqueductal stenosis for years without any symptoms, and a head trauma, hemorrhage, or infection could suddenly invoke those symptoms and worsen the blockage.
A rare syndrome characterized mainly by congenital cataracts, ataxia, mental retardation, abnormal amino acid metabolism and long, thin fingers.