SNP Shot: Genomic Insights

Pseudoxanthoma elasticum (PXE) is a condition that worsens over time, marked by the buildup of calcium and other minerals (mineralization) in the body's elastic fibers. These fibers are part of the connective tissue responsible for the strength and flexibility of various bodily structures.

In individuals with PXE, this mineralization primarily affects elastic fibers in the skin, eyes, and blood vessels. Less commonly, it can also impact the digestive tract. Skin manifestations of PXE often include small, yellowish bumps (papules) on the neck, armpits, and in skin folds near joints. Eye problems can arise, such as peau d'orange, a change in the pigmented cells of the retina, the light-sensitive layer at the back of the eye. Another eye issue is angioid streaks, caused by small cracks in Bruch's membrane, the tissue layer beneath the retina. Retinal bleeding and scarring can also occur, potentially leading to vision impairment.

The mineralization of arteries, which carry blood throughout the body, can lead to other PXE symptoms. These may include artery narrowing (arteriosclerosis) and claudication, characterized by pain and cramping during exercise due to reduced blood flow to the limbs. In rare instances, bleeding from blood vessels in the digestive system can occur.

Inheritance:

PXE is usually inherited in an autosomal recessive pattern. This means that a person must inherit two copies of a mutated gene, one from each parent, to develop the condition. Typically, the parents are carriers, each possessing one copy of the mutated gene but exhibiting no symptoms. However, in rare cases, an affected individual may have one parent who is also affected and one parent who appears unaffected, resembling autosomal dominant inheritance (where one copy of a mutated gene is enough to cause the condition). In these specific PXE cases, the seemingly unaffected parent carries an ABCC6 gene mutation. The affected child inherits two altered genes, one from each parent. This phenomenon, where an autosomal recessive condition appears to be inherited in a dominant manner, is known as pseudodominance.