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Pseudoxanthoma elasticum (PXE)

 

Alternative Name : Grönblad–Strandberg syndrome

Definition:
Pseudoxanthoma elasticum (PXE) is a genetic disease that causes fragmentation and mineralization of elastic fibers in some tissues. The most common problems arise in the skin and eyes, and later in blood vessels in the form of premature atherosclerosis. PXE is caused by autosomal recessive mutations in the ABCC6 gene on the short arm of chromosome 16.

PXE is a rare condition that many doctors  may not  know much about, even though it was first described more than 100 years ago. It causes the elastic fibres that are normally found in the skin, the retina of the eyes and the blood vessels to become calcified and break up, so losing their elasticity.

The reported prevalence of pseudoxanthoma elasticum is about 1:25,000. Females are twice as likely to be affected as males. The disease occurs in all ethnicities, but Afrikaners are more likely to have PXE as a result of a founder effect (i.e. it was relatively prevalent in the small group of people from whom most Afrikaners descend).

Symptoms:
The most characteristic initial symptom of PXE is discolouring of the skin around the sides of the neck.
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Generally, affected areas of skin appear thickened. In some people, small yellowy-orange papules between 2mm and 5mm in diameter form groups, or join together as larger plaques. When this happens, the skin takes on a cobblestone or ‘plucked chicken’ appearance.

These skin changes then tend to appear in the skin flexures of the elbows, groins and knees, and under the arms. As the skin loses its elasticity, it becomes soft, floppy and wrinkled, hanging in folds. Although these changes do no physical harm, emotionally they cause great distress because of their appearance. However, it’s unusual for widespread areas of the skin to be affected.

Other problems are potentially more serious. Slow calcification of the thin elastic fibres of the retina at the back of the eyes eventually affects about 60 per cent of PXE sufferers, usually by the time they reach middle age. Sometimes this leads to a complete loss of central vision.
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In some cases, the blood vessels are affected, which makes heart attacks and strokes more likely. The painful condition of the legs called intermittent claudication – where blood can’t get to the muscles easily to deliver oxygen to the tissues – is also more common. Gastrointestinal bleeding is another problem that some people with PXE experience.

Causes:
80% of clinical cases of pseudoxanthoma elasticum have detectable mutations in the ABCC6 gene. Mutations in almost all parts of the gene have been described, of all types (missense, nonsense, splice alteration, insertion, small deletion or large deletion). Although there have been reports of autosomal dominant inheritance, the inheritance is typically autosomal recessive (both parents need to be carriers, and there is a 25% chance that a child will inherit both abnormal copies of the gene and therefore develop the condition).

Strong genetic linkage was found with mutations in the ABCC6 gene, which codes for the MRP6 protein, but the exact mechanism by which this protein (which is a membrane transporter from the large ATP-binding cassette transporter family) influences the disease course is unknown; the protein is expressed in most organs, but mainly in the liver and kidney. It is unclear in what way this would lead to abnormalities in skin, eyes and blood vessels. It is thought that particular mutations do not cause a more severe or less severe form of the disease. Given the variations in age of onset and severity it is likely that other unknown risk factors (genetic and dietary) may be involved.  One study suggested that mutations causing total absence of an MRP6 protein caused a more severe disease,[10] but this could not be confirmed in a subsequent case series.

Premature atherosclerosis is also associated with mutations in the ABCC6 gene, even in those without PXE. A syndrome almost indistinguishable from hereditary PXE has been described in patients with hemoglobinopathies (sickle-cell disease and thalassemia) through a poorly understood mechanism.  In addition, there appears to be another PXE-like syndrome with a similar phenotype but as a result of problems with another gene, gamma-glutamyl carboxylase

Diagnosis
The presence of calcium in elastic fibers, as revealed by microscopic examination of biopsied skin, unequivocally establishes the diagnosis of PXE.

Treatment
PXE cannot be cured, but plastic surgery can treat PXE skin lesions, and laser surgery is used to prevent or slow the progression of vision loss. Excessive blood loss due to bleeding into the gastrointestinal tract or other organ systems may be treated by transfusion. Mitral valve prolapse (protrusion of one or both cusps of the mitral heart valve back into the atrium during heart beating) can be corrected by surgery, if necessary.

Measures should be taken to prevent or lessen cardiovascular complications. People with PXE should control their cholesterol and blood pressure, and maintain normal weight. They should exercise for cardiovascular health and to prevent or reduce claudication later in life. They should also avoid the use of tobacco, thiazide antihypertensive drugs, blood thinners like coumadin, and nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen. In addition, they should avoid strain, heavy lifting, and contact sports, since these activities could trigger retinal and gastrointestinal bleeding.

People with PXE should have regular eye examinations by an ophthalmologist and report any eye problems immediately. Regular check-ups with a physician are also recommended, including periodic blood pressure readings.

Some people have advocated a calcium-restricted diet, but it is not yet known whether this aids the problems brought about by PXE. It is known, however, that calcium-restriction can lead to bone disorders.

Prognosis
The prognosis is for a normal life span with an increased chance of cardiovascular and circulatory problems, hypertension, gastrointestinal bleeding, and impaired vision. However, now that the gene for PXE has been identified, the groundwork for research to provide effective treatment has been laid. Studying the role of the ABCC6 protein in elastic fibers may lead to drugs that will ameliorate or arrest the problems caused by PXE.

Genetic tests are now available that can provide knowledge needed to both diagnose PXE in symptomatic persons and predict it prior to the onset of symptoms in persons at risk. Prenatal diagnosis of PXE, by testing fetal cells for mutations in the ABCC6 gene, can be done in early pregnancy by procedures such as amniocentesis or chorionic villus sampling. For most people, PXE is compatible with a reasonably normal life, and prenatal diagnosis is not likely to be highly desired.

Genetic testing to predict whether an at-risk child will develop PXE may be helpful for medical management. A child who is found to carry a mutation can be monitored more closely for eye problems and bleeding, and can begin the appropriate lifestyle changes to prevent cardiovascular problems.

 

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Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://en.wikipedia.org/wiki/Pseudoxanthoma_elasticum
http://www.bbc.co.uk/health/physical_health/conditions/pxe1.shtml
http://medical-dictionary.thefreedictionary.com/pseudoxanthoma+elasticum
http://www.aocd.org/skin/dermatologic_diseases/pseudoxanthoma-elasticum.html

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Don’t let your diet ruin the big occasion

What you eat and drink plays a critical role in helping you to look and feel your best when you walk down the red carpet.

Although most of us will only ever experience LA’s Kodak Theatre from the comfort of our sitting rooms, we can all relate to the desire to slip effortlessly into our favourite dress to create a special entrance. If the event is just days away, you don’t have time to lose any significant amount of weight, but you can help yourself to feel and appear slimmer by overcoming the dreaded bloat. Scientific studies establishing the best “antibloat” plans are virtually nonexistent, but we are lucky enough to have a few enlightened doctors and medical herbalists to give us some assistance.

Go salt free. As Graham MacGregor, a Professor of Medicine at St Georges Hospital, southwest London, explains:   When we eat excess salt, our bodies hold on to extra water to dilute its presence. Such retention of salt causes us to hang on to as much as 1.5 litres (two and a half pints) of fluid, causing weight gains of around 1kg (2-3lb). Switching to a low salt intake can cause losses of this fluid.  Bloating and swollen ankles can  deflate   within days.  Exactly the same principles apply to the menstrual cycle, where many women swell up. A reduced salt intake can often relieve symptoms dramatically,  he says.

The best way to do this is to cut out all processed foods
, since 75 per cent of our salt comes from these. Stick with sugar-free muesli or eggs for breakfast and lean meat and fish with lots of salads and vegetables at other meals, with fruit for snacks.

Eat slowly. Dr John Hunter, a consultant physician at Ad-denbrooke’s Hospital, Cambridge, and an authority on food in relation to the gut, advises:  Treat your gut with respect. Eating very quickly and drinking fluids at the same time makes it more likely that you will swallow a lot of air, leading to bloating. Avoid chewing gum, too, since it to can cause you to swallow extra air.

Destress.
It is worth taking it easy and trying to relax before a big night out.  It is not uncommon for people to hyperventilate without being aware that they are doing so,  Dr Hunter says.  During the day large volumes of air can be swallowed in this way, resulting in bloating.  Chamomile tea is certainly worth trying, to help you to calm down. As medical herbalists such as Dr Ann Walker, of Reading University, tell us, its active volatile oils contain the compound apigenin, which acts on the same parts of the brain and nervous system as those affected by antianxiety drugs and can calm both our minds and our digestive tracts.

Swap to soya milk. Lactose is the sugar in milk and if not digested properly by the enzyme lactase in the small intestine, it passes into the colon to be fermented by bacteria that produce gases and cause bloating. Lactose intolerance can be absolute and for life, yet some of us can experience transient symptoms. Swapping to soya milk for a few days may just help to relieve a bout of bloating. Avoid vegetables with gassy notoriety.Burbulence, the various windy symptoms that arise from gas in the gut, is said to be encouraged by peas, broccoli, Brussels sprouts and cabbage. Avoiding these is probably a good idea on your   Oscar  day.

Beans, too, can notoriously cause bloating, as Dr W. Grant Thompson, professor emeritus at the University of Ottawa, explains in his book Gut Reactions:   Beans contain a   wind factor’ consisting of the complex saccharides stachyose and raffinose. These cannot be absorbed by the intestine because the enzymes necessary for their digestion do not exist in humans. Certain colon bacteria are capable of metabolising these substances, thereby releasing hydrogen, methane, and carbon dioxide.

Avoid fizzy drinks.
Both Dr Hunter and Dr Thompson also suggest the elimination of carbonated drinks to avoid abdominal distension. This is well worth doing both the day before your big event and on the evening itself to help to maintain your smooth and elegant lines, although personally I do not think a glass of champagne will hurt.

From:Times on line