Pseudoxanthoma elasticum, also known as Gronbland Stranberg syndrome, is a genetic condition affecting the elastic fibers present in the retina of the eyes, the blood vessels and the skin causing them to lose their elasticity. Presence of calcifications are often found in these areas, making the fibers lose their flexibility and strength. Elastic fibers, or elastin, are components of connective tissues that provide flexibility and strength to different body structures.
Pseudoxanthoma elasticum has been known to affect people regardless of race, but females are more predisposed to acquire this condition than males. The age of onset is varied since it may occur from infancy to adulthood and is usually inherited from the parents in an autosomal recessive pattern. In an autosomal recessive pattern, both parents must carry the defective genes for pseudoxanthoma elasticum to be passed on to their child. In some cases, it may be inherited in an autosomal dominant manner, where only one defective gene from either of the parents is enough to cause the condition.
Genetically, pseudoxanthoma elasticum is said to be due to mutations of the ABCC6 gene. The exact process of how the mutations occur, however, is still unknown.
The ABCC6 gene codes for a protein which helps to transport substances acoss the cell membrane. Mutations lead to a nonfuctioning or absent protein which impairs the transport of substances and disrupts the cell’s normal activities.
Pseudoxanthoma elasticum is often asymptomatic, and this is the reason why the diagnosis is often made later in a person’s life. The first signs are typically changes in the skin at the neck area which resemble plucked chicken skin with yellowish discoloration.
Later on, skin changes become noticeable in areas of the underarm, the front surface of the elbow, the groin, the area surrounding the navel, and at the back of the knees. As time goes by, the skin in these affected areas may start to become wrinkled, soft, and loose.
Another group of symptoms of pseudoxanthoma elasticum occur elsewhere in the body. The retina may start to show signs of web-like structures called angioid streaks. Further calcification in the retina may lead to hemorrhage which, if left uncontrolled, may lead to central vision loss. In the area of the heart, calcification of the blood vessels may increase blood pressure, diminish peripheral pulses, and induce chest pain. These predispose patients to develop coronary artery disease and myocardial infarction or heart attack. Bleeding in the gastrointestinal tract may also occur.
There is no available cure for pseudoxanthoma elasticum. The management of patients with this condition is often directed towards the prevention of complications. Patients are taught to quit smoking, avoid contact sports, maintain ideal weight, avoid fatty food, and to avoid drugs that may cause bleeding. Doctors who care for patients with pseudoxanthoma elasticum generally monitor the organ systems to watch out for signs of complication.
Merck Manuals: Pseudoxanthoma Elasticum
Genetics Home Reference: Pseudoxanthoma Elasticum
MedicineNet.com: Pseudoxanthoma Elasticum (PXE)