Pseudoxanthoma Elasticum (PXE) is a genetic, inherited, systemic connective tissue disorder, which affects the elastic tissue of the skin, eyes, gastrointestinal (digestive tract), and the cardiovascular system (heart and blood vessels).
What are the other Names for this Condition? (Also known as/Synonyms)
- Elastosis Dystrophica Syndrome
- Systematized Elastorrhexis
- Systemic Elastorrhexis
What is Pseudoxanthoma Elasticum? (Definition/Background Information)
- Pseudoxanthoma Elasticum (PXE) is a genetic, inherited, systemic connective tissue disorder, which affects the elastic tissue of the skin, eyes, gastrointestinal (digestive tract), and the cardiovascular system (heart and blood vessels)
- The connective tissues provide strength and flexibility to various structures in the body. PXE is a progressive disorder in which calcium and other minerals deposits accumulate in the elastic fibers, which form part of the connective tissues. This leads to degeneration or fragmentation of the elastic fibers in certain organs (skin, eyes, blood vessels, etc.)
- In Pseudoxanthoma Elasticum, mutations occur in the ABCC6 gene. Though both autosomal dominant and recessive pattern of inheritance are seen, most cases are inherited in an autosomal recessive manner (in which both copies of the genes from the parents have to be mutated to develop this disease)
- Any individual can be affected by this disorder, but it has been observed that females are affected twice as much as males
- The condition is treated through lifestyle changes, medications, and surgery if required. The majority of the patients with Pseudoxanthoma Elasticum have normal life expectancy, if symptoms and complications of the condition are managed appropriately
Who gets Pseudoxanthoma Elasticum? (Age and Sex Distribution)
- Pseudoxanthoma Elasticum can affect any individual. The prevalence ratio for this condition is estimated at 1 in 50,000
- Both genders are affected, although females are affected twice as much as males
- The condition is observed worldwide; all racial and ethnic groups may be affected. However, Afrikaners seems to have higher incidence rate of PXE, when compared to other races
What are the Risk Factors for Pseudoxanthoma Elasticum? (Predisposing Factors)
The risk factors for Pseudoxanthoma Elasticum include:
- Gender: Females have an increased risk of PXE
- Race: Predominance of this condition is observed in Afrikaners
- Genetic factors: Pseudoxanthoma Elasticum is an inherited condition; having a positive family history increases the risk
It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.
Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.
What are the Causes of Pseudoxanthoma Elasticum? (Etiology)
Pseudoxanthoma Elasticum is a genetic disorder caused by mutations in the ABCC6 gene and inherited from the parents.
- The ABCC6 gene provides instructions for making a protein, called multidrug resistance protein-6 (MRP6 protein), which is mostly found in cells of the kidney and liver. It helps in the transportation of certain substances across the cell membranes
- Alterations or changes that occur in the ABCC6 gene affecting the protein function. This affects the transportation of certain substances from blood that is distributed to various parts of the body
- Due to this, an abnormal collection of various substances (calcium, mineral, etc.) occur in the elastic fibers of the organs, such as the skin, blood vessels, and tissues, leading to their breakdown
- Autosomal dominant pattern of inheritance is seen in rare cases, though the majority of cases are inherited in an autosomal recessive pattern
Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly functioning gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.
Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children, born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).
What are the Signs and Symptoms of Pseudoxanthoma Elasticum?
Pseudoxanthoma Elasticum affects the skin first with later involvement of the eyes, heart, blood vessels, and digestive tract. The signs and symptoms of PXE depend upon the organ or body system affected.
Signs and symptoms related to the skin include:
- Presence of small, yellowish, raised lesions mostly on the neck, armpit, groin, and inside of the elbow and knee
- The skin becomes lax and redundant
- Oblique crease on the chin
Signs and symptoms related to the eye include:
- Vision abnormalities
- Retinal hemorrhage with loss of vision
Signs and symptoms related to the heart and blood vessels include:
- Angina (chest pain)
- Myocardial infarction/heart attack
- Intermittent claudication: Leg pain during walking that resolves at rest
Signs and symptoms related to the gastrointestinal (digestive) tract include:
- Hematemesis (vomiting blood)
- Melena (blood in stool)
How is Pseudoxanthoma Elasticum Diagnosed?
The diagnosis of Pseudoxanthoma Elasticum may include:
- Complete evaluation of medical history along with a thorough physical examination
- Laboratory tests that may be performed include:
- Complete blood count
- Serum iron for iron deficiency anemia that occurs due to excess bleeding
- Stool for occult blood
- Serum calcium and phosphate levels
- Imaging tests such as:
- Echocardiogram to check for the involvement of the mitral valve (heart valve)
- Coronary angiography, if needed to examine the function of the arteries supplying the heart
Other diagnostic procedures that may need to be performed include:
- Ophthalmic examination to check for retinopathy, angioid streaks, and retinal hemorrhage
- When GI bleeding is seen, endoscopy and colonoscopy is recommended
- When claudication or diminished peripheral pulses are noticed, then ankle or brachial blood pressure using Doppler methods may be beneficial
Many clinical conditions may have similar signs and symptoms. Your health care provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.
What are the possible Complications of Pseudoxanthoma Elasticum?
Complications due to Pseudoxanthoma Elasticum could include:
- Cosmetic issues due to skin lesions
- Blood loss from the digestive tract
- Iron deficiency anemia due to blood loss
- Prolapsed mitral valve (left-sided heart valve): It is a medical condition in which the mitral valve does not work well and the flaps of the valve are floppy and fail to close tightly
- Retinal hemorrhages may lead to loss of vision
- Claudication: Muscle pain or cramps while walking, due to involvement of the leg blood vessels
- Hypertension (high blood pressure)
- Myocardial infarction, also known as heart attack, caused by blood clot that stops the flow of blood to the heart
- Cerebral (brain) hemorrhage that could be fatal
How is Pseudoxanthoma Elasticum Treated?
The treatment measures for Pseudoxanthoma Elasticum may include:
- General measures that involve modifications to one’s lifestyle include:
- Smoking avoidance can help in an effective management of PXE
- A low calcium diet is always recommended. Individuals have to follow their physician’s instruction regarding diet and exercise
- Hemorrhages may be avoided by taking vitamin A, C, E and zinc supplements
- Contact sports must be avoided to protect the eyes from any injury or damage
An ophthalmologist should regularly monitor the condition of individuals with PXE
- Medication treatment:
- Non-steroid anti-inflammatory drugs (NSAIDs) should be avoided to reduce the risk of hemorrhage
- Standard management procedures should be followed to treat high-risk coronary heart disease
- Pentoxifyline may help in reducing blood viscosity, but it may also increase the risk of hemorrhage
- Interferon alfa-2a may be useful in the treatment of the condition
- Surgical intervention: Plastic surgery is helpful in correcting the cosmetic issues related to sagging skin
The treatment measures recommended by the healthcare provider will depend on the combination of signs and symptoms of each individual, and their health status.
How can Pseudoxanthoma Elasticum be Prevented?
- Currently, there are no specific methods or guidelines to prevent Pseudoxanthoma Elasticum since it is a genetic condition
- Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
- If there is a family history of the condition, then genetic counseling will help assess risks before planning for a child
- Active research is currently being performed to explore the possibilities of treatment and prevention of inherited genetic disorders
What is the Prognosis of Pseudoxanthoma Elasticum? (Outcomes/Resolutions)
- Individuals with Pseudoxanthoma Elasticum have a normal life expectancy, though bleeding and vascular conditions require proper evaluation and management
- Early diagnosis and implementation of treatment measures are vital for a good and favorable prognosis
Additional and Relevant Useful Information for Pseudoxanthoma Elasticum:
- Pseudoxanthoma Elasticum is the only genetic disorder in which the discoverer of the gene associated with the disorder is a non-medical person. Sharon F. Terry, who worked along with her husband Patrick F. Terry, discovered the gene in the year 2000. Both their children were affected by Pseudoxanthoma Elasticum
- The disease was first described by the French dermatologist Rigal in 1881; it was later named by Darier in 1896
- Earlier, PXE was known by names such as Elastosis Dystrophica Syndrome and Systemic Elastorrhexis
What are some Useful Resources for Additional Information?
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
1 AMS Circle Bethesda, MD 20892-3675
Phone: (301) 495-4484
Toll-Free: (877) 226-4267
TTY: (301) 565-2966
Fax: (301) 718-6366
References and Information Sources used for the Article:
http://ghr.nlm.nih.gov/condition/pseudoxanthoma-elasticum (accessed on 5/12/2015)
http://www.dermnetnz.org/systemic/pxe.html (accessed on 5/12/2015)
http://www.ncbi.nlm.nih.gov/books/NBK1113/ (accessed on 5/12/2015)
http://www.omim.org/entry/177850 (accessed on 5/12/2015)
Helpful Peer-Reviewed Medical Articles:
Combrinck, M., Gilbert, J. D., &Byard, R. W. (2011).Pseudoxanthoma elasticum and sudden death. J Forensic Sci, 56(2), 418-422. doi: 10.1111/j.1556-4029.2010.01647.x
Georgalas, I., Tservakis, I., Papaconstaninou, D., Kardara, M., Koutsandrea, C., & Ladas, I. (2011).Pseudoxanthoma elasticum, ocular manifestations, complications and treatment.ClinExpOptom, 94(2), 169-180. doi: 10.1111/j.1444-0938.2010.00559.x
Li, Q., &Uitto, J. (2012). Heritable ectopic mineralization disorders: the paradigm of pseudoxanthomaelasticum. J Invest Dermatol, 132(E1), E15-19. doi: 10.1038/skinbio.2012.5
Uitto, J., Bercovitch, L., Terry, S. F., & Terry, P. F. (2011). Pseudoxanthoma elasticum: progress in diagnostics and research towards treatment : Summary of the 2010 PXE International Research Meeting. Am J Med Genet A, 155A(7), 1517-1526. doi: 10.1002/ajmg.a.34067
Zimmo, L., Rudarakanchana, N., Thompson, M., Hamady, M. S., Cheshire, N. J., & Bicknell, C. D. (2013).Renal artery aneurysm formation secondary to pseudoxanthomaelasticum. J VascSurg, 57(3), 842-844. doi: 10.1016/j.jvs.2012.09.016
Bergen, A. A., Plomp, A. S., Schuurman, E. J., Terry, S., Breuning, M., Dauwerse, H., ... & Jacoline, B. (2000). Mutations in ABCC6 cause pseudoxanthoma elasticum. Nature genetics, 25(2), 228.
Le Saux, O., Urban, Z., Tschuch, C., Csiszar, K., Bacchelli, B., Quaglino, D., ... & Bercovitch, L. (2000). Mutations in a gene encoding an ABC transporter cause pseudoxanthoma elasticum. Nature genetics, 25(2), 223.
Ringpfeil, F., Lebwohl, M. G., Christiano, A. M., & Uitto, J. (2000). Pseudoxanthoma elasticum: mutations in the MRP6 gene encoding a transmembrane ATP-binding cassette (ABC) transporter. Proceedings of the National Academy of Sciences, 97(11), 6001-6006.
Struk, B., Cai, L., Zäch, S., Ji, W., Chung, J., Lumsden, A., ... & Goldsmith, L. A. (2000). Mutations of the gene encoding the transmembrane transporter protein ABC-C6 cause pseudoxanthoma elasticum. Journal of molecular medicine, 78(5), 282-286.
Hu, X., Plomp, A. S., van Soest, S., Wijnholds, J., de Jong, P. T., & Bergen, A. A. (2003). Pseudoxanthoma elasticum: a clinical, histopathological, and molecular update. Survey of ophthalmology, 48(4), 424-438.