Salih myopathy (myopathy Salih) - Gen TTN.
Salih myopathy is a hereditary muscular disease that affects skeletal muscles. This disease is characterized by weakness of the skeletal muscle becomes apparent in early childhood. Affected individuals show delayed development of motor, such as sitting, getting up and walking skills. Other signs and symptoms of the disease include contractures that restrict movement of the neck and back, scoliosis and dilated cardiomyopathy. Dilated cardiomyopathy weakens the heart muscle, which prevents the heart to pump blood efficiently. Signs and symptoms of dilated cardiomyopathy may include arrhythmia, shortness of breath, fatigue and swelling of legs and feet. Usually cardiac abnormalities associated with myopathy Salih manifest in childhood after skeletal muscle abnormalities. Heart disease gets worse quickly and often leads to heart failure and sudden death in adolescence or early adulthood.
This process is due to mutations in the TTN gene, located on the long arm of chromosome 2 (2q31). This gene encodes a protein called titin, which is in many sarcomeres muscle cell types, including cardiomyocytes. This protein has several functions within the sarcomeres. One of its most important tasks is to provide structure, flexibility and stability to these cellular structures. In addition, it also plays a role in chemical signaling and assembly of new sarcomeres.
They have identified at least 2 mutations in the TTN gene in people with myopathy Salih. These genetic changes occur near the end of the titin gene coding and lead to an abnormally short version of titin protein. The defective protein disrupts the function of the sarcomeres, preventing the skeletal and cardiac muscle develops and act normally. These muscle abnormalities underlying the characteristic features of myopathy Salih, including skeletal muscle weakness and dilated cardiomyopathy.
This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with myopathy Salih, by complete PCR amplification of the exons of the gene TTN, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).