| Danon disease | |
|---|---|
| Other names | Lysosomal glycogen storage disease with normal acid maltase activity, formerly GSD-IIb, GSD due to LAMP-2 deficiency |
| Specialty | Endocrinology  |
Danon disease (or glycogen storage disease Type IIb) is a metabolic disorder. [1] Danon disease is an X-linked lysosomal and glycogen storage disorder associated with hypertrophic cardiomyopathy, skeletal muscle weakness, and intellectual disability. [2] It is inherited in an X-linked dominant pattern. [1]
Males
In males the symptoms of Danon disease are more severe. Features of Danon disease in males are:[ citation needed ]
Females
In females the symptoms of Danon disease are less severe. Common symptoms of Danon disease in females are:[ citation needed ]
Although the genetic cause of Danon disease is known, the mechanism of disease is not well understood. Danon disease involves a genetic defect (mutation) in a gene called LAMP2, which results in a change to the normal protein structure. While the function of the LAMP2 gene is not well understood, it is known that LAMP2 protein is primarily located in small structures within cells called lysosomes.[ citation needed ]
It is associated with LAMP2. [4] The status of this condition as a GSD has been disputed. [5]
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person's medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
Testing Resources The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional. Orphanet lists international laboratories offering diagnostic testing for this condition.
RP-A501 is an AAV-based gene therapy aimed to restore the LAMP-2 gene which is defective in male patients with Danon Disease and how to cure it. [6] Cardiac transplantation has been performed as a treatment; however, most patients die early in life. [7]
Danon disease was characterized by Moris Danon in 1981. [8] Dr. Danon first described the disease in 2 boys with heart and skeletal muscle disease (muscle weakness), and intellectual disability.
The first case of Danon disease reported in the Middle East was a family diagnosed in the eastern region of United Arab Emirates with a new LAMP2 mutation; discovered by the Egyptian cardiologist Dr. Mahmoud Ramadan [9] the associate professor of Cardiology in Mansoura University [10] (Egypt) after doing genetic analysis for all the family members in Bergamo, Italy, where 6 males were diagnosed as Danon disease patients and 5 female were diagnosed as carriers; as published in Al-Bayan newspaper on 20 February 2016 [11] making this family the largest one with patients and carriers of Danon disease.
Danon disease has overlapping symptoms with another rare genetic condition called 'Pompe' disease. Microscopically, muscles from Danon disease patients appear similar to muscles from Pompe disease patients. However, intellectual disability is rarely, if ever, a symptom of Pompe disease. Negative enzymatic or molecular genetic testing for Pompe disease can help rule out this disorder as a differential diagnosis.[ citation needed ]
Kocher–Debré–Semelaigne syndrome(KDSS) is hypothyroidism in infancy or childhood characterised by lower extremity or generalized muscular hypertrophy (Herculean appearance), myxoedema, short stature, and cognitive impairment.
Glycogen storage disease type V, also known as McArdle's disease, is a metabolic disorder, one of the metabolic myopathies, more specifically a muscle glycogen storage disease, caused by a deficiency of myophosphorylase. Its incidence is reported as one in 100,000, roughly the same as glycogen storage disease type I.
A glycogen storage disease is a metabolic disorder caused by a deficiency of an enzyme or transport protein affecting glycogen synthesis, glycogen breakdown, or glucose breakdown, typically in muscles and/or liver cells.
Fabry disease, also known as Anderson–Fabry disease, is a rare genetic disease that can affect many parts of the body, including the kidneys, heart, brain, and skin. Fabry disease is one of a group of conditions known as lysosomal storage diseases. The genetic mutation that causes Fabry disease interferes with the function of an enzyme that processes biomolecules known as sphingolipids, leading to these substances building up in the walls of blood vessels and other organs. It is inherited in an X-linked manner.
Alpha-mannosidosis is a lysosomal storage disorder, first described by Swedish physician Okerman in 1967. In humans it is known to be caused by an autosomal recessive genetic mutation in the gene MAN2B1, located on chromosome 19, affecting the production of the enzyme alpha-D-mannosidase, resulting in its deficiency. Consequently, if both parents are carriers, there will be a 25% chance with each pregnancy that the defective gene from both parents will be inherited, and the child will develop the disease. There is a two in three chance that unaffected siblings will be carriers. In livestock alpha-mannosidosis is caused by chronic poisoning with swainsonine from locoweed.
Glycogen storage disease type II, also called Pompe disease, and formerly known as GSD-IIa. It is an autosomal recessive metabolic disorder which damages muscle and nerve cells throughout the body. It is caused by an accumulation of glycogen in the lysosome due to deficiency of the lysosomal acid alpha-glucosidase enzyme. GSD-II and Danon disease are the only glycogen storage diseases with a defect in lysosomal metabolism, and Pompe disease was the first glycogen storage disease to be identified, in 1932 by the Dutch pathologist J. C. Pompe.
Phosphofructokinase deficiency is a rare muscular metabolic disorder, with an autosomal recessive inheritance pattern.
Inborn errors of metabolism form a large class of genetic diseases involving congenital disorders of enzyme activities. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances (substrates) into others (products). In most of the disorders, problems arise due to accumulation of substances which are toxic or interfere with normal function, or due to the effects of reduced ability to synthesize essential compounds. Inborn errors of metabolism are often referred to as congenital metabolic diseases or inherited metabolic disorders. Another term used to describe these disorders is "enzymopathies". This term was created following the study of biodynamic enzymology, a science based on the study of the enzymes and their products. Finally, inborn errors of metabolism were studied for the first time by British physician Archibald Garrod (1857–1936), in 1908. He is known for work that prefigured the "one gene-one enzyme" hypothesis, based on his studies on the nature and inheritance of alkaptonuria. His seminal text, Inborn Errors of Metabolism, was published in 1923.
In medicine, myopathy is a disease of the muscle in which the muscle fibers do not function properly. Myopathy means muscle disease. This meaning implies that the primary defect is within the muscle, as opposed to the nerves or elsewhere.
Hereditary inclusion body myopathies (HIBM) are a group of rare genetic disorders which have different symptoms. Generally, they are neuromuscular disorders characterized by muscle weakness developing in young adults. Hereditary inclusion body myopathies comprise both autosomal recessive and autosomal dominant muscle disorders that have a variable expression (phenotype) in individuals, but all share similar structural features in the muscles.
Mitochondrial myopathies are types of myopathies associated with mitochondrial disease. Adenosine triphosphate (ATP), the chemical used to provide energy for the cell, cannot be produced sufficiently by oxidative phosphorylation when the mitochondrion is either damaged or missing necessary enzymes or transport proteins. With ATP production deficient in mitochondria, there is an over-reliance on anaerobic glycolysis which leads to lactic acidosis either at rest or exercise-induced.
Glycogen storage disease type IV (GSD IV), or Andersen's Disease, is a form of glycogen storage disease, which is caused by an inborn error of metabolism. It is the result of a mutation in the GBE1 gene, which causes a defect in the glycogen branching enzyme. Therefore, glycogen is not made properly and abnormal glycogen molecules accumulate in cells; most severely in cardiac and muscle cells. The severity of this disease varies on the amount of enzyme produced. GSD IV is autosomal recessive, which means each parent has a mutant copy of the gene, but show no symptoms of the disease. Having an autosomal recessive inheritance pattern, males and females are equally likely to be affected by Andersen's disease. Classic Andersen's disease typically becomes apparent during the first few months after the patient is born. Approximately 1 in 20,000 to 25,000 newborns have a glycogen storage disease. Andersen's disease affects 1 in 800,000 individuals worldwide, with 3% of all GSDs being type IV. The disease was described and studied first by Dorothy Hansine Andersen.
Glycogen storage disease type III (GSD III) is an autosomal recessive metabolic disorder and inborn error of metabolism (specifically of carbohydrates) characterized by a deficiency in glycogen debranching enzymes. It is also known as Cori's disease in honor of the 1947 Nobel laureates Carl Cori and Gerty Cori. Other names include Forbes disease in honor of clinician Gilbert Burnett Forbes (1915–2003), an American physician who further described the features of the disorder, or limit dextrinosis, due to the limit dextrin-like structures in cytosol. Limit dextrin is the remaining polymer produced after hydrolysis of glycogen. Without glycogen debranching enzymes to further convert these branched glycogen polymers to glucose, limit dextrinosis abnormally accumulates in the cytoplasm.
Centronuclear myopathies (CNM) are a group of congenital myopathies where cell nuclei are abnormally located in the center of muscle cells instead of their normal location at the periphery.
Metabolic myopathies are myopathies that result from defects in biochemical metabolism that primarily affect muscle. They are generally genetic defects that interfere with muscle's ability to create energy, causing a low ATP reservoir within the muscle cell.
Neutral lipid storage disease is a congenital autosomal recessive disorder characterized by accumulation of triglycerides in the cytoplasm of leukocytes, muscle, liver, fibroblasts, and other tissues. It commonly occurs as one of two subtypes, cardiomyopathic neutral lipid storage disease (NLSD-M), or ichthyotic neutral lipid storage disease (NLSD-I) which is also known as Chanarin–Dorfman syndrome), which are characterized primarily by myopathy and ichthyosis, respectively. Normally, the ichthyosis that is present is typically non-bullous congenital ichthyosiform erythroderma which appears as white scaling.
Hoffmann syndrome is a rare form of hypothyroid myopathy and is not to be confused with Werdnig-Hoffmann disease.
Acquired non-inflammatory myopathy (ANIM) is a neuromuscular disorder primarily affecting skeletal muscle, most commonly in the limbs of humans, resulting in a weakness or dysfunction in the muscle. A myopathy refers to a problem or abnormality with the myofibrils, which compose muscle tissue. In general, non-inflammatory myopathies are a grouping of muscular diseases not induced by an autoimmune-mediated inflammatory pathway. These muscular diseases usually arise from a pathology within the muscle tissue itself rather than the nerves innervating that tissue. ANIM has a wide spectrum of causes which include drugs and toxins, nutritional imbalances, acquired metabolic dysfunctions such as an acquired defect in protein structure, and infections.
X-linked myopathy with excessive autophagy (XMEA) is a rare childhood onset disease characterized by slow progressive vacuolation and atrophy of skeletal muscle. There is no known cardiac or intellectual involvement.
Autophagic vacuolar myopathy (AVM) consists of multiple rare genetic disorders with common histological and pathological features on muscle biopsy. The features highlighted are vacuolar membranes of the autophagic vacuoles having sarcolemmal characteristics and an excess of autophagic vacuoles. There are currently five types of AVM identified. The signs and symptoms become more severe over the course of the disease. It begins with an inability to pick up small objects and progresses to difficulty in walking. The age of onset varies from early childhood to late adulthood, affecting people of all ages.