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 chromosome 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.
Joubert syndrome is a rare autosomal recessive genetic disorder that affects the cerebellum, an area of the brain that controls balance and coordination.
Limb–girdle muscular dystrophy (LGMD) is a genetically heterogeneous group of rare muscular dystrophies that share a set of clinical characteristics. It is characterised by progressive muscle wasting which affects predominantly hip and shoulder muscles. LGMD usually has an autosomal pattern of inheritance. It currently has no known cure or treatment.
Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis, management, and counselling people with genetic disorders would be considered part of medical genetics.
Vitelliform macular dystrophy is an irregular autosomal dominant eye disorder which can cause progressive vision loss. This disorder affects the retina, specifically cells in a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. The condition is characterized by yellow, slightly elevated, round structures similar to the yolk of an egg.
Oguchi disease is an autosomal recessive form of congenital stationary night blindness associated with fundus discoloration and abnormally slow dark adaptation.
ATP-binding cassette, sub-family A (ABC1), member 4, also known as ABCA4 or ABCR, is a protein which in humans is encoded by the ABCA4 gene.
Bestrophin-1 (Best1) is a protein that, in humans, is encoded by the BEST1 gene.
EEM syndrome is an autosomal recessive congenital malformation disorder affecting tissues associated with the ectoderm, and also the hands, feet and eyes.
A Finnish heritage disease is any genetic disease or disorder that is significantly more common in people whose ancestors were ethnic Finns, natives of Finland and Northern Sweden (Meänmaa) and Northwest Russia. There are 36 rare diseases regarded as Finnish heritage diseases. The diseases are not restricted to Finns; they are genetic diseases with far wider distribution in the world, but due to founder effects and genetic isolation they are more common in Finns.
Jalili syndrome is a genetic disorder characterized by the combination of cone-rod dystrophy of the retina and amelogenesis imperfecta. It was characterized in 1988 by Dr. I. K. Jalili and Dr. N. J. D. Smith, following the examination of 29 members of an inbred Arab family living within the Gaza Strip.
Hyperglycerolemia, also known as glycerol kinase deficiency (GKD), is a genetic disorder where the enzyme glycerol kinase is deficient resulting in a build-up of glycerol in the body. Glycerol kinase is responsible for synthesizing triglycerides and glycerophospholipids in the body. Excess amounts of glycerol can be found in the blood and/ or urine. Hyperglycerolmia occurs more frequently in males. Hyperglycerolemia is listed as a "rare disease", which means it affects less than 200,000 people in the US population, or less than about 1 in 1500 people.
Genetic studies on Arabs refers to the analyses of the genetics of ethnic Arab people in the Middle East and North Africa. Arabs are genetically diverse as a result of their intermarriage and mixing with indigenous people of the pre-Islamic Middle East and North Africa following the Arab and Islamic expansion. Genetic ancestry components related to the Arabian Peninsula display an increasing frequency pattern from west to east over North Africa. A similar frequency pattern exist across northeastern Africa with decreasing genetic affinities to groups of the Arabian Peninsula along the Nile river valley across Sudan and the more they go south. This genetic cline of admixture is dated to the time of Arab migrations to the Maghreb and northeast Africa.
Hypotrichosis with juvenile macular dystrophy is an extremely rare congenital disease characterized by sparse hair growth (hypotrichosis) from birth and progressive macular corneal dystrophy.
Spastic ataxia-corneal dystrophy syndrome is an autosomally resessive disease. It has been found in an inbred Bedouin family. It was first described in 1986. A member of the family who was first diagnosed with this disease also had Bartter syndrome. It was concluded by its first descriptors Mousa-Al et al. that the disease is different from a disease known as corneal-cerebellar syndrome that had been found in 1985.
Boucher-Neuhäuser syndrome is a very rare genetic disorder which is characterized by a triad consisting of cerebellar ataxia, chorioretinal dystrophy, and hypogonadism.
X-linked cone-rod dystrophy, type 1 is a rare progressive genetic disorder of the vision which is characterized by progressive myopia, photophobia, abnormal color perception, lowered photopic electroretinigraphic response, and macular retinal pigment epithelium granularity. The severity of the symptoms is variable. Peripheral vision is unaffected in most of the cases. It is one of the three types of X-linked cone-rod dystrophy.
Autosomal recessive bestrophinopathy is a rare genetic disorder characterized by central vision loss, retinopathy, absence of an electrooculogram light rise, and decreased electroretinogram. Other findings include dispersed punctate flecks, macular neurosensory retina fluid build-up, hyperopia, macular thinning, and angle-closure glaucoma.
Progressive bifocal chorioretinal atrophy, also known for its abbreviations PBCRA or CRAPB, is a rare, slowly progressive, autosomal dominant syndrome characterized by relatively large-sized atrophic hole-shaped lesions in the macular and nasal retina, myopia, low visual acuity, and nystagmus. It has been described in one family from Scotland and two families from France. The condition is caused by point mutations in a region in the long arm of chromosome 6 (6q16.2) that has been found responsible for the pathogenesis of other macular dystrophies.
