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.
Ehlers–Danlos syndromes (EDS) are a group of 13 genetic connective-tissue disorders. Symptoms often include loose joints, joint pain, stretchy velvety skin, and abnormal scar formation. These may be noticed at birth or in early childhood. Complications may include aortic dissection, joint dislocations, scoliosis, chronic pain, or early osteoarthritis. The current classification was last updated in 2017, when a number of rarer forms of EDS were added.
A rare disease is any disease that affects a small percentage of the population. In some parts of the world, the term orphan disease describes a rare disease whose rarity results in little or no funding or research for treatments, without financial incentives from governments or other agencies. Orphan drugs are medications targeting orphan diseases.
Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease. This field is considered necessary for the implementation of genomic medicine. The process integrates:
The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) is one of the institutes and centers that make up the National Institutes of Health, an agency of the United States Department of Health and Human Services (HHS).
Preimplantation genetic diagnosis is the genetic profiling of embryos prior to implantation, and sometimes even of oocytes prior to fertilization. PGD is considered in a similar fashion to prenatal diagnosis. When used to screen for a specific genetic disease, its main advantage is that it avoids selective abortion, as the method makes it highly likely that the baby will be free of the disease under consideration. PGD thus is an adjunct to assisted reproductive technology, and requires in vitro fertilization (IVF) to obtain oocytes or embryos for evaluation. Embryos are generally obtained through blastomere or blastocyst biopsy. The latter technique has proved to be less deleterious for the embryo, therefore it is advisable to perform the biopsy around day 5 or 6 of development.
Sanfilippo syndrome, also known as mucopolysaccharidosis type III (MPS III), is a rare lifelong genetic disease that mainly affects the brain and spinal cord. It is caused by a problem with how the body breaks down certain large sugar molecules called glycosaminoglycans (also known as GAGs or mucopolysaccharides). In children with this condition, these sugar molecules build up in the body and eventually lead to damage of the central nervous system and other organ systems.
Action Medical Research, previously The National Fund for Research into Crippling Diseases, is a major British medical research charity, founded in 1952, that funds research to prevent and treat disease and disability in babies and children.
Norrie disease is a rare X-linked recessive genetic disorder that primarily affects the eyes and almost always leads to blindness. It is caused by mutations in the Norrin cystine knot growth factor gene, also referred to as Norrie Disease Pseudoglioma (NDP) gene. Norrie disease manifests with vision impairment either at birth, or within a few weeks of life, following an ocular event like retinal detachment and is progressive through childhood and adolescence. It generally begins with retinal degeneration, which occurs before birth and results in blindness at birth (congenital) or early infancy, usually by 3 months of age.
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.
Reproductive medicine is a branch of medicine concerning the male and female reproductive systems. It encompasses a variety of reproductive conditions, their prevention and assessment, as well as their subsequent treatment and prognosis.
Macrodontia is a type of localized gigantism in which teeth are larger than normal. Macrodontia seen in permanent teeth is thought to affect around 0.03 to 1.9 percent of the worldwide population. Generally, patients with macrodontia have one or two teeth in their mouth that is abnormally large; however, single tooth growth is seen in a number of cases as well.
The genetics and abortion issue is an extension of the abortion debate and the disability rights movement. Since the advent of forms of prenatal diagnosis, such as amniocentesis and ultrasound, it has become possible to detect the presence of congenital disorders in the fetus before birth. Specifically, disability-selective abortion is the abortion of fetuses that are found to have non-fatal mental or physical defects detected through prenatal testing. Many prenatal tests are now considered routine, such as testing for Down syndrome. Women who are discovered to be carrying fetuses with disabilities are often faced with the decision of whether to abort or to prepare to parent a child with disabilities.
Orphanet is an organisation and knowledge base dedicated to rare diseases as well as corresponding diagnosis, orphan drugs, clinical trials and expert networks.
The Royal Osteoporosis Society (ROS), formerly the National Osteoporosis Society, established in 1986, is the only UK-wide charity dedicated to improving the prevention, diagnosis and treatment of osteoporosis. It is based in Camerton, Somerset, England.
A termination for medical reasons (TFMR) is an induced abortion motivated by medical indications involving the fetus or mother. In some countries, health risks are the only basis for obtaining a legal abortion. Prenatal screening can allow early diagnosis, and abortion if desired or necessary. Some medical organizations advocate the offer of diagnostic testing by chorionic villi sampling, and amniocentesis to all pregnant women, as a matter of course.
Intersex people are born with natural variations in physical and sex characteristics including those of the chromosomes, gonads, sex hormones, or genitals that, according to the UN Office of the High Commissioner for Human Rights, "do not fit the typical definitions for male or female bodies". Such variations may involve genital ambiguity, and combinations of chromosomal genotype and sexual phenotype other than XY-male and XX-female. Preimplantation genetic diagnosis allows the elimination of embryos and fetuses with intersex traits and thus has an impact on discrimination against intersex people.
Dopamine transporter deficiency syndrome (DTDS), also known as infantile parkinsonism-dystonia, is a rare movement disorder that causes progressively worsening dystonia and parkinsonism. It is the first known inherited dopamine 'transportophathy.'
Christine Patch is a nurse and genetic counsellor. She is a Principal Staff Scientist in Genomic Counselling in the Society and Ethics Research group, part of Wellcome Connecting Science, based on the Wellcome Genome Campus. She is also the Clinical Lead for Genetic Counselling at Genomics England, and a former President of the European Society of Human Genetics.
