Wolff-Parkinson-White Syndrome (cont.)

Mutations in the PRKAG2 gene cause Wolff-Parkinson-White syndrome.

A small percentage of all cases of Wolff-Parkinson-White syndrome are caused by mutations in the PRKAG2 gene. Some people with these mutations also have features of hypertrophic cardiomyopathy, a form of heart disease that enlarges and weakens the heart (cardiac) muscle. The PRKAG2 gene provides instructions for making a protein that is part of an enzyme called AMP-activated protein kinase (AMPK). This enzyme helps sense and respond to energy demands within cells. It is likely involved in the development of the heart before birth, although its role in this process is unknown.

Researchers are uncertain how PRKAG2 mutations lead to the development of Wolff-Parkinson-White syndrome and related heart abnormalities. Research suggests that these mutations alter the activity of AMP-activated protein kinase in the heart, although it is unclear whether the genetic changes overactivate the enzyme or reduce its activity. Studies indicate that changes in AMP-activated protein kinase activity allow a complex sugar called glycogen to build up abnormally within cardiac muscle cells. Other studies have found that altered AMP-activated protein kinase activity is related to changes in the regulation of certain ion channels in the heart. These channels, which transport positively charged atoms (ions) into and out of cardiac muscle cells, play critical roles in maintaining the heart's normal rhythm.

In most cases, the cause of Wolff-Parkinson-White syndrome is unknown.

Source: MedicineNet.com
http://www.medicinenet.com/wolff-parkinson-white_syndrome/article.htm