Table 3.

Molecules related to PXS, function, and nature of association

Molecules related to PXS	Known function	Nature of association
Lysyl oxidase-like 1 (LOXL1) [28,32,34,78]	Copper-dependent monoamine oxidase secreted by fibrogenic cells. Catalyzes covalent cross-linking of collagen and elastin in ECM formation	-Gene polymorphisms linked to PXS in multiple studies
		-Protein present at site of pathology
Clusterin [14]	Clearance of cellular debris and apoptosis	-Clusterin deficiency associated with PXS.
		-Clusterin present in PXM deposits
Homocysteine and human cell metabolic enzymes (MTHFR MTR, MTRR, MTHFD1, CBS) [46,47]	Amino acids that participate in multiple metabolic processes.	Increased plasma levels associated with PXS
Glutathione transferase [50,51,56,57]	It conjugates those toxic products with glutathione, protecting cells from oxidative damage	-Linkage of null genotype of the GST gene with PXS
CNTNAP2 (Caspr 2) [58,60]	Regulation of potassium channels at neuron membranes. Possible role in membrane stabilization	-CNTNAP2 gene polymorphism associated with PXS
MMPs (MMP1) [15-17,49]	Extracellular matrix maintenance	-MMP1 gene polymorphism associated with PXS
Adenosine receptors [45]	Adenosine regulates aqueous humor secretion. Intraocular pressure are regulated through adenosine receptors	-A3 receptor mRNA and protein selectively up regulated in eyes with PXS
TNF-α [65]	Has dual action depending on the type of receptor activated.	-Increased expression of TNF-α shifts the balance and activates the low affinity TNF-R1 receptor leading to cell death
	High affinity TNF-R2 receptor has neuroprotective function while low affinity TNF-R1 receptors activation leads to cell death.