What is Bethlem myopathy?
Bethlem myopathy is a genetic disorder that affects the skeletal muscles and the connective tissue. The skeletal muscles are the muscles that are used for movement. The connective tissue is the part of our body that provides strength, support, and flexibility for the skin, joints, and other structures of the body. It is like the glue that holds the parts of our body together. Individuals who have Bethlem myopathy typically have proximal muscle weakness (muscle weakness close to the torso) and contractures. Contractures are joint stiffness that results in limited mobility of joints. Individuals with Bethlem myopathy most often have contractures of the long finger, elbows, and ankles. Symptoms of Bethlem myopathy can begin anywhere from prenatally (before birth) to adulthood. For most individuals, symptoms are limited to muscle weakness and contractures, and only rarely will have breathing problems.
Bethlem myopathy is caused by genetic variants that are damaging to the collagen VI genes (COL6A1, COL6A2, and COL6A3). There are other genetic conditions that are also caused by genetic variants to the collagen six genes. People who have Bethlem myopathy typically have the mildest symptoms.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/bethlem-myopathy-109941/overview/67021 • DATE UPDATED: 2019-02-21
Online Mendelian Inheritance in Man, OMIM®. Johns Hopkins University, Baltimore, MD. MIM Number: 158810: October 4, 2018: https://omim.org/entry/158810 Accessed 21FEB19
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Genetics home reference, Collagen VI-related myopathy, https://ghr.nlm.nih.gov/condition/collagen-vi-related-myopathy Accessed 21FEB19