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Jervell and Lange-Nielsen syndrome is a condition that causes profound hearing loss from birth and a disruption of the heart's normal rhythm (arrhythmia). This disorder is a form of long QT syndrome, which is a heart condition that causes the heart (cardiac) muscle to take longer than usual to recharge between beats. Beginning in early childhood, the irregular heartbeats increase the risk of fainting (syncope) and sudden death.
Jervell and Lange-Nielsen syndrome is uncommon; it affects an estimated 1.6 to 6 per 1 million people worldwide. This condition has a higher prevalence in Denmark, where it affects at least 1 in 200,000 people.
Mutations in the KCNE1 and KCNQ1 genes cause Jervell and Lange-Nielsen syndrome.
The KCNE1 and KCNQ1 genes provide instructions for making proteins that work together to form a channel across cell membranes. These channels transport positively charged potassium atoms (ions) out of cells. The movement of potassium ions through these channels is critical for maintaining the normal functions of inner ear structures and cardiac muscle.
About 90 percent of cases of Jervell and Lange-Nielsen syndrome are caused by mutations in the KCNQ1 gene; KCNE1 mutations are responsible for the remaining cases. Mutations in these genes alter the usual structure and function of potassium channels or prevent the assembly of normal channels. These changes disrupt the flow of potassium ions in the inner ear and in cardiac muscle, leading to hearing loss and an irregular heart rhythm characteristic of Jervell and Lange-Nielsen syndrome.
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of a child with an autosomal recessive disorder are not affected, but are carriers of one copy of the mutated gene. Some carriers of a KCNQ1 or KCNE1 mutation have signs and symptoms affecting the heart, but their hearing is usually normal.
'''Jervell and Lange-Nielsen syndrome''' is a condition that causes profound hearing loss and arrhythmia, it is a type of long QT syndrome. This condition is inherited in an autosomal recessive pattern, and affects an estimated 1.6 to 6 in 1 million children, and is responsible for less than 10 percent of all cases of long QT syndrome. Like long QT syndrome, Jervell and Lange-Nielsen syndrome is a a heart condition that causes the cardiac muscle to take longer than usual to recharge between beats. If untreated, the irregular heartbeats can lead to fainting, seizures, or sudden death. Mutations in the KCNE1 and KCNQ1 genes cause Jervell and Lange-Nielsen syndrome. The proteins produced by these two genes work together to form a Potassium channel that transports positively charged potassium ions out of cell (biology). The movement of potassium ions through these channels is critical for maintaining the normal functions of the inner ear and cardiac muscle. About 90 percent of cases of Jervell and Lange-Nielsen syndrome are caused by mutations in the KCNQ1 gene; KCNE1 mutations are responsible for the remaining 10 percent of cases. Mutations in these genes alter the usual structure and function of potassium channels or prevent the assembly of normal channels. These changes disrupt the flow of potassium ions in the inner ear and in cardiac muscle, leading to the hearing loss and irregular heart rhythm characteristic of Jervell and Lange-Nielsen syndrome. ''This article incorporates public domain text from [http://ghr.nlm.nih.gov The U.S. National Library of Medicine]'' [ Read More ]