Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body fat and increased muscle size. Affected individuals have up to twice the usual amount of muscle mass in their bodies. They also tend to have increased muscle strength. Learn more about myostatin-related muscle hypertrophy and what causes it.
Skeletal Muscle Fiber
Image by Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014
Summary
Muscle-Organ Crosstalk (Myokine)
Image by Bente Pedersen/Wikimedia
Muscle-Organ Crosstalk (Myokine)
Muscle-Organ Crosstalk:Focus on Immunometabolism.
Irisin and Cathepsin B enhance BDNF production and thereby hippocampal neurogenesis. IL-6 inhibits appetite and stimulates lipolysis. IL-6 also plays a role in decreasing the amount of visceral fat. IL-6, irisin and meteorin-like are involved in turning white adipose tissue into a brown phenotype. IL-15 retards skin aging. IL-6, decorin, FGF-2 and IGF-1 positively influence bone formation. Myostatin negatively influence bone formation. Musclin, LIF, IL-4, IL-6, IL-7, and IL-15 are involved in mediating muscle hypertrophy, whereas myostatin obstructs muscle hypertrophy. IL-6 and BDNF stimulate AMPK activation and hence fat oxidation. IL-6 e stimulates glucose uptake and hepatic glucose output during exercise. IL-6 induces the expression of GLP-1 by the L cells of the intestine leading to enhanced insulin secretion. IL-6 exerts anti-inflammatory effects by inhibiting TNF production and by stimulating IL-1ra and IL-10 production. IL-6 enhances cortisol production, leading to neutrocytosis and lymphopenia. FSTL-1 has beneficial effects on endothelial function and revascularization of atherosclerotic blood vessels. Osteoprotegerin, angiogenin, and IL-6 possess beta-cell protective actions against inflammatory cytokines. Adapted with permission from Severinsen and Pedersen (2020).
Image by Bente Pedersen/Wikimedia
What Is Myostatin-Related Muscle Hypertrophy?
Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body fat and increased muscle size. Affected individuals have up to twice the usual amount of muscle mass in their bodies. They also tend to have increased muscle strength. Myostatin-related muscle hypertrophy is not known to cause any medical problems, and affected individuals are intellectually normal.
Source: MedlinePlus Genetics
Additional Materials (2)
Skeletal muscle diagram
Image by Created by myself.
Skeletal Muscle Fiber.
Skeletal Muscle Fiber.
Image by Blausen.com staff (2014). "Medical gallery of Blausen Medical 201
Skeletal muscle diagram
Created by myself.
Skeletal Muscle Fiber.
Blausen.com staff (2014). "Medical gallery of Blausen Medical 201
Is It Common?
Illustration of rare disease incidence
Image by mcmurryjulie/Pixabay
Illustration of rare disease incidence
Image by mcmurryjulie/Pixabay
How Common Is Myostatin-Related Muscle Hypertrophy?
It is not known how many people are diagnosed with myostatin-related muscle hypertrophy. Unfortunately for the rare diseases, there's often not a calculated incidence or prevalence. There is no official method for tracking these conditions.
Source: Genetic and Rare Diseases (GARD) Information Center
Causes
Multiple genomic variants shown on different strands of DNA double-helix
Image by National Human Genome Research Institute
Multiple genomic variants shown on different strands of DNA double-helix
Image shows genomic variants represented by the letter “V.” Some are shared among individuals, while others are specific to one person.
Image by National Human Genome Research Institute
What Causes Myostatin-Related Muscle Hypertrophy?
Variants (also known as mutations) in the MSTN gene cause myostatin-related muscle hypertrophy. The MSTN gene provides instructions for making a protein called myostatin, which is active in muscles used for movement (skeletal muscles) both before and after birth. This protein normally limits muscle growth, ensuring that muscles do not grow too large. Variants that reduce the production of functional myostatin lead to an overgrowth of muscle tissue.
Source: MedlinePlus Genetics
Additional Materials (1)
Genomic variant
There are roughly 4 to 5 million such genomic variants in an individual’s genome. These variants may be unique to that individual or occur in others as well.
Image by National Human Genome Research Institute
Genomic variant
National Human Genome Research Institute
MSTN Gene
Ideogram of human chromosome 2
Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.
Ideogram of human chromosome 2
Selected genes, traits, and disorders associated with the chromosome listed; (blue and violet) regions reflecting the unique patterns of light and dark bands seen on human chromosomes stained to allow viewing through a light microscope; (red) the centromere, or constricted portion, of each chromosome; (yellow) chromosomal regions that vary in staining intensity and sometimes are called hererochromatin (meaning “different color”); (lines between yellow) variable regions, called stalks, that connect a very small chromosome arm (a “satellite”) to the chromosome.
Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.
MSTN Gene: Myostatin
Normal Function
The MSTN gene provides instructions for making a protein called myostatin. This protein is part of the transforming growth factor beta (TGFβ) superfamily, which is a group of proteins that help control the growth and development of tissues throughout the body. Myostatin is found almost exclusively in muscles used for movement (skeletal muscles), where it is active both before and after birth. This protein normally limits muscle growth, ensuring that muscles do not grow too large. Myostatin has been studied extensively in mice, cows, and other animals, and it appears to have a similar function in humans.
Researchers are studying myostatin as a potential treatment for various muscular dystrophies that cause muscle weakness and wasting (atrophy).
Health Conditions Related to Genetic Changes
Myostatin-related muscle hypertrophy
At least one variant (also known as a mutation) in the MSTN gene has been found to cause myostatin-related muscle hypertrophy, a rare condition characterized by increased muscle mass and strength. The variant, which is written as IVS1+5G>A, disrupts the way the gene's instructions are used to make myostatin. As a result, cells produce little or no functional myostatin. A loss of this protein in muscle cells leads to an overgrowth of muscle tissue. It does not appear to cause any other medical problems in affected individuals.
Other Names for This Gene
GDF-8
GDF8
GDF8_HUMAN
growth differentiation factor 8
Genomic Location
The MSTN gene is found on chromosome 2.
Source: MedlinePlus Genetics
Inheritance
Human Genome - Infant and DNA
Image by TheVisualMD
Human Genome - Infant and DNA
Human Genome - Inheritance
Image by TheVisualMD
How Is Myostatin-Related Muscle Hypertrophy Inherited?
Myostatin-related muscle hypertrophy has a pattern of inheritance known as incomplete autosomal dominance. People with a variant in both copies of the MSTN gene in each cell (homozygotes) have significantly increased muscle mass and strength. People with a variant in one copy of the MSTN gene in each cell (heterozygotes) also have increased muscle bulk, but to a lesser degree.
Source: MedlinePlus Genetics
Diagnosis
Genetic testing
Image by genome.gov
Genetic testing
Genetic testing fact sheet
Image by genome.gov
How Is Myostatin-Related Muscle Hypertrophy Diagnosed?
MSTN gene. Clinical genetic testing for this condition appears to be available on a limited basis.
Source: Genetic and Rare Diseases (GARD) Information Center
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Myostatin-Related Muscle Hypertrophy
Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body fat and increased muscle size. Affected individuals have up to twice the usual amount of muscle mass in their bodies. They also tend to have increased muscle strength. Learn more about myostatin-related muscle hypertrophy and what causes it.