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Genetic Penetrance
Penetrance in genetics is the proportion of individuals carrying a particular variant (or allele) of a gene (genotype) that also expresses an associated trait (phenotype). In medical genetics, the penetrance of a disease-causing mutation is the proportion of individuals with the mutation that exhibit clinical symptoms among all individuals with such mutation. For example: If a mutation in the gene responsible for a particular autosomal dominant disorder has 95% penetrance, then 95% of those with the mutation will go on to develop the disease, showing its phenotype, whereas 5% will not.   Penetrance only refers to whether an individual with a specific genotype exhibits any phenotypic signs or symptoms, and is not to be confused with variable expressivity which is to what extent or degree the symptoms for said disease are shown (the expression of the phenotypic trait). Meaning that, even if the same disease-causing mutation affects separate individuals, the expressivity will vary. ...
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BRCA1 And BRCA2 Mutations And Absolute Cancer Risk
Breast cancer type 1 susceptibility protein is a protein that in humans is encoded by the ''BRCA1'' () gene. Orthologs are common in other vertebrate species, whereas invertebrate genomes may encode a more distantly related gene. ''BRCA1'' is a human tumor suppressor gene (also known as a caretaker gene) and is responsible for repairing DNA. ''BRCA1'' and ''BRCA2'' are unrelated proteins, but both are normally expressed in the cells of breast and other tissues, where they help repair damaged DNA, or destroy cells if DNA cannot be repaired. They are involved in the repair of chromosomal damage with an important role in the error-free repair of DNA double-strand breaks. If ''BRCA1'' or ''BRCA2'' itself is damaged by a BRCA mutation, damaged DNA is not repaired properly, and this increases the risk for breast cancer. ''BRCA1'' and ''BRCA2'' have been described as "breast cancer susceptibility genes" and "breast cancer susceptibility proteins". The predominant allele has a normal, ...
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Epigenetic Mechanisms
In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in addition to" the traditional (DNA sequence based) genetic mechanism of inheritance. Epigenetics usually involves a change that is not erased by cell division, and affects the regulation of gene expression. Such effects on cellular and physiological traits may result from environmental factors, or be part of normal development. The term also refers to the mechanism of changes: functionally relevant alterations to the genome that do not involve mutation of the nucleotide sequence. Examples of mechanisms that produce such changes are DNA methylation and histone modification, each of which alters how genes are expressed without altering the underlying DNA sequence. Further, non-coding RNA sequences have been shown to play a key role in the r ...
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Smoking
Smoking is a practice in which a substance is combusted, and the resulting smoke is typically inhaled to be tasted and absorbed into the bloodstream of a person. Most commonly, the substance used is the dried leaves of the tobacco plant, which have been rolled with a small rectangle of paper into an elongated cylinder called a cigarette. Other forms of smoking include the use of a smoking pipe or a bong. Smoking is primarily practised as a route of administration for psychoactive chemicals because the active substances within the burnt dried plant leaves vaporize and can be airborne-delivered into the respiratory tract, where they are rapidly absorbed into the bloodstream of the lungs and then reach the central nervous system. In the case of tobacco smoking, these active substances are a mixture of aerosol particles that includes the pharmacologically active alkaloid nicotine, which stimulates the nicotinic acetylcholine receptors in the brain. Other notable active ...
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Breastfeeding
Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a Breast pump, pump and then fed to the infant. The World Health Organization (WHO) recommend that breastfeeding begin within the first hour of a baby's birth and continue as the baby wants. Health organizations, including the WHO, recommend breastfeeding exclusively for six months. This means that no other foods or drinks, other than vitamin D, are typically given. The WHO recommends exclusive breastfeeding for the first 6 months of life, followed by continued breastfeeding with appropriate complementary foods for up to 2 years and beyond. Of the 135 million babies born every year, only 42% are breastfed within the first hour of life, only 38% of mothers practice exclusive breastfeeding during the first six months, and 58% of mothers continue breastfeeding up to the age of two years and beyond. Breastfee ...
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Pregnancy
Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs following sexual intercourse, vaginal intercourse, but can also occur through assisted reproductive technology procedures. A pregnancy may end in a Live birth (human), live birth, a miscarriage, an Abortion#Induced, induced abortion, or a stillbirth. Childbirth typically occurs around 40 weeks from the start of the Menstruation#Onset and frequency, last menstrual period (LMP), a span known as the Gestational age (obstetrics), ''gestational age''; this is just over nine months. Counting by Human fertilization#Fertilization age, ''fertilization age'', the length is about 38 weeks. Implantation (embryology), Implantation occurs on average 8–9 days after Human fertilization, fertilization. An ''embryo'' is the term for the deve ...
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Ovarian Cancer
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different cell types including epithelial cells, germ cells, and stromal cells. When these cells become abnormal, they have the ability to divide and form tumors. These cells can also invade or spread to other parts of the body. When this process begins, there may be no or only vague symptoms. Symptoms become more noticeable as the cancer progresses. These symptoms may include bloating, vaginal bleeding, pelvic pain, abdominal swelling, constipation, and loss of appetite, among others. Common areas to which the cancer may spread include the lining of the abdomen, lymph nodes, lungs, and liver. The risk of ovarian cancer increases with age. Most cases of ovarian cancer develop after menopause. It is also more common in women who have ovulated ...
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Breast Cancer
Breast cancer is a cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with Metastatic breast cancer, distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin. Risk factors for developing breast cancer include obesity, a Sedentary lifestyle, lack of physical exercise, alcohol consumption, hormone replacement therapy during menopause, ionizing radiation, an early age at Menarche, first menstruation, having children late in life (or not at all), older age, having a prior history of breast cancer, and a family history of breast cancer. About five to ten percent of cases are the result of an inherited genetic predisposition, including BRCA mutation, ''BRCA'' mutations among others. Breast ...
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Stress (biology)
Stress, whether physiological, biological or psychological, is an organism's response to a stressor, such as an environmental condition or change in life circumstances. When stressed by stimuli that alter an organism's environment, multiple systems respond across the body. In humans and most mammals, the autonomic nervous system and Hypothalamic–pituitary–adrenal axis, hypothalamic-pituitary-adrenal (HPA) axis are the two major systems that respond to stress. Two well-known hormones that humans produce during stressful situations are adrenaline and cortisol. The Sympathoadrenal system, sympathoadrenal medullary axis (SAM) may activate the fight-or-flight response through the sympathetic nervous system, which dedicates energy to more relevant bodily systems to Acute stress reaction, acute adaptation to stress, while the parasympathetic nervous system returns the body to homeostasis. The second major physiological stress-response center, the HPA axis, regulates the release ...
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Drug
A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug injection, injection, smoking, ingestion, absorption (skin), absorption via a dermal patch, patch on the skin, suppository, or sublingual administration, dissolution under the tongue. In pharmacology, a drug is a chemical substance, typically of known structure, which, when administered to a living organism, produces a biological effect. A pharmaceutical drug, also called a medication or medicine, is a chemical substance used to pharmacotherapy, treat, cure, preventive healthcare, prevent, or medical diagnosis, diagnose a disease or to promote well-being. Traditionally drugs were obtained through extraction from medicinal plants, but more recently also by organic synthesis. Pharmaceutical drugs may be used for a limited duration, or on a re ...
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Alcoholic Beverage
Drinks containing alcohol (drug), alcohol are typically divided into three classes—beers, wines, and Distilled beverage, spirits—with alcohol content typically between 3% and 50%. Drinks with less than 0.5% are sometimes considered Non-alcoholic drink, non-alcoholic. Many societies have a distinct drinking culture, where alcoholic drinks are integrated into party, parties. Most countries have Alcohol law, laws regulating the production, sale, and consumption of alcoholic beverages. Some regulations require the labeling of the percentage alcohol content (as ABV or Alcohol proof, proof) and the use of a Alcohol warning label, warning label. List of countries with alcohol prohibition, Some countries Prohibition, ban the consumption of alcoholic drinks, but they are legal in most parts of the world. The temperance movement advocates against the consumption of alcoholic beverages. The global alcohol industry, alcoholic drink industry exceeded $1.5 trillion in 2017. Alcohol is o ...
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Dieting
Dieting is the practice of eating food in a regulated way to decrease, maintain, or increase body weight, or to prevent and treat diseases such as diabetes and obesity. As weight loss depends on calorie intake, List of diets, different kinds of Calorie restriction, calorie-reduced diets, such as those emphasising particular macronutrients (low-fat diet, low-fat, low-carbohydrate diet, low-carbohydrate, etc.), have been shown to be no more effective than one another. As weight regain is common, diet success is best predicted by long-term adherence. Regardless, the outcome of a diet can vary widely depending on the individual. The first popular diet was "Banting", named after William Banting. In his 1863 pamphlet, ''Letter on Corpulence, Addressed to the Public'', he outlined the details of a particular low-carbohydrate, low-calorie diet that led to his own dramatic weight loss. Some guidelines recommend dieting to Weight loss, lose weight for people with weight-related health pr ...
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