A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development, or it can be inherited from two parents who are carriers of a faulty gene or from a parent with the disorder. When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA.
Lipodystrophy syndromes are a group of genetic or acquired disorders in which the body is unable to produce and maintain healthy fat tissue. The medical condition is characterized by abnormal or degenerative conditions of the body's adipose tissue. A more specific term, lipoatrophy, is used when describing the loss of fat from one area. This condition is also characterized by a lack of circulating leptin which may lead to osteosclerosis. The absence of fat tissue is associated with insulin resistance, hypertriglyceridemia, non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome.
Cockayne syndrome (CS), also called Neill-Dingwall syndrome, is a rare and fatal autosomal recessive neurodegenerative disorder characterized by growth failure, impaired development of the nervous system, abnormal sensitivity to sunlight (photosensitivity), eye disorders and premature aging. Failure to thrive and neurological disorders are criteria for diagnosis, while photosensitivity, hearing loss, eye abnormalities, and cavities are other very common features. Problems with any or all of the internal organs are possible. It is associated with a group of disorders called leukodystrophies, which are conditions characterized by degradation of neurological white matter. There are two primary types of Cockayne syndrome: Cockayne syndrome type A (CSA), arising from mutations in the ERCC8 gene, and Cockayne syndrome type B (CSB), resulting from mutations in the ERCC6 gene.
Behr syndrome is characterized by the association of early-onset optic atrophy with spinocerebellar degeneration resulting in ataxia, pyramidal signs, peripheral neuropathy and developmental delay.
Heřmanský–Pudlák syndrome is an extremely rare autosomal recessive disorder which results in oculocutaneous albinism, bleeding problems due to a platelet abnormality, and storage of an abnormal fat-protein compound. It is thought to affect around 1 in 500,000 people worldwide, with a significantly higher occurrence in Puerto Ricans, with a prevalence of 1 in 1800. Many of the clinical research studies on the disease have been conducted in Puerto Rico.
McLeod syndrome is an X-linked recessive genetic disorder that may affect the blood, brain, peripheral nerves, muscle, and heart. It is caused by a variety of recessively inherited mutations in the XK gene on the X chromosome. The gene is responsible for producing the Kx protein, a secondary supportive protein for the Kell antigen on the red blood cell surface.
An immunoproteasome is a type of proteasome that degrades ubiquitin-labeled proteins found in the cytoplasm in cells exposed to oxidative stress and proinflammatory stimuli. In general, proteasomes consist of a regulatory and a catalytic part. Immunoproteasomes are induced by interferon gamma and oxidative stress, which in the cell triggers the transcription of three catalytic subunits that do not occur in the classical proteasome. Another possible variation of proteasome is the thymoproteasome, which is located in the thymus and folds to present peptides to naive T cells.
Laminopathies are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear lamina. They are included in the more generic term nuclear envelopathies that was coined in 2000 for diseases associated with defects of the nuclear envelope. Since the first reports of laminopathies in the late 1990s, increased research efforts have started to uncover the vital role of nuclear envelope proteins in cell and tissue integrity in animals.
Proteasome subunit beta type-8 as known as 20S proteasome subunit beta-5i is a protein that in humans is encoded by the PSMB8 gene. This protein is one of the 17 essential subunits that contributes to the complete assembly of 20S proteasome complex. In particular, proteasome subunit beta type-5, along with other beta subunits, assemble into two heptameric rings and subsequently a proteolytic chamber for substrate degradation. This protein contains "Chymotrypsin-like" activity and is capable of cleaving after large hydrophobic residues of peptide. The eukaryotic proteasome recognized degradable proteins, including damaged proteins for protein quality control purpose or key regulatory protein components for dynamic biological processes. The constitutive subunit beta1, beta2, and beta 5 can be replaced by their inducible counterparts beta1i, 2i, and 5i when cells are under the treatment of interferon-γ. The resulting proteasome complex becomes the so-called immunoproteasome. An essential function of the modified proteasome complex, the immunoproteasome, is the processing of numerous MHC class-I restricted T cell epitopes.
Chronic recurrent multifocal osteomyelitis (CRMO) is a rare condition (1:1,000,000), in which the bones have lesions, inflammation, and pain. It is called multifocal because it can appear in different parts of the body, primarily bones, and osteomyelitis because it is very similar to that disease, although CRMO appears to be without any infection.
Congenital generalized lipodystrophy is an extremely rare autosomal recessive condition, characterized by an extreme scarcity of fat in the subcutaneous tissues. It is a type of lipodystrophy disorder where the magnitude of fat loss determines the severity of metabolic complications. Only 250 cases of the condition have been reported, and it is estimated that it occurs in 1 in 10 million people worldwide.
Familial partial lipodystrophy, also known as Köbberling–Dunnigan syndrome, is a rare genetic metabolic condition characterized by the loss of subcutaneous fat.
X-linked spinal muscular atrophy type 2, also known as arthrogryposis multiplex congenita X-linked type 1 (AMCX1), is a rare neurological disorder involving death of motor neurons in the anterior horn of spinal cord resulting in generalised muscle wasting (atrophy). The disease is caused by a mutation in UBA1 gene and is passed in an X-linked recessive manner by carrier mothers to affected sons.
Nakajo syndrome, also called nodular erythema with digital changes, is a rare autosomal recessive congenital disorder first reported in 1939 by A. Nakajo in the offspring of consanguineous parents. The syndrome can be characterized by erythema, loss of body fat in the upper part of the body, and disproportionately large eyes, ears, nose, lips, and fingers.
Keratosis linearis with ichthyosis congenita and sclerosing keratoderma syndrome is a rare cutaneous condition characterized by ichthyosis and keratoderma.
Majeed syndrome is an inherited skin disorder characterized by chronic recurrent multifocal osteomyelitis, congenital dyserythropoietic anemia and a neutrophilic dermatosis. It is classified as an autoinflammatory bone disorder. The condition is found in people with two defective copies of the LPIN2 gene. LPIN2 encodes lipin-2 which is involved in lipid metabolism. The pathogenesis of this mutation with the clinical manifestations has not been elucidated.
Progeroid syndromes (PS) are a group of rare genetic disorders that mimic physiological aging, making affected individuals appear to be older than they are. The term progeroid syndrome does not necessarily imply progeria, which is a specific type of progeroid syndrome.
VEXAS syndrome is an adult-onset autoinflammatory disease primarily affecting males, caused by a somatic mutation of the UBA1 gene in hematopoietic progenitor cells. The name VEXAS is an acronym deriving from the core features of disease:
Autoinflammatory diseases (AIDs) are a group of rare disorders caused by dysfunction of the innate immune system. They are characterized by periodic or chronic systemic inflammation, usually without the involvement of adaptive immunity.
