Genetic disorder in the context of "Huntington's disease"

Health has a variety of definitions, which have been used for different purposes over time. In general, it refers to physical and emotional well-being, especially that associated with normal functioning of the human body, absent of disease, pain (including mental pain), or injury.

Health can be promoted by encouraging healthful activities, such as regular physical exercise and adequate sleep, and by reducing or avoiding unhealthful activities or situations, such as smoking or excessive stress. Some factors affecting health are due to individual choices, such as whether to engage in a high-risk behavior, while others are due to structural causes, such as whether the society is arranged in a way that makes it easier or harder for people to get necessary healthcare services. Still, other factors are beyond both individual and group choices, such as genetic disorders.

Endogamy is the cultural practice of marrying within a specific social group, religious denomination, caste, or ethnic group, rejecting any from outside of the group or belief structure as unsuitable for marriage or other close personal relationships. Its opposite, exogamy, describes the social norm of marriage outside of the group.

Endogamy is common in many cultures and ethnic groups. Several religious and ethnic religious groups are traditionally more endogamous, although sometimes mating outside of the group occurs with the added dimension of requiring marital religious conversion. This permits an exogamous marriage, as the convert, by accepting the partner's religion, becomes accepted within the endogamous group. Endogamy may result in a higher rate of recessive gene–linked genetic disorders.

Lactose intolerance is caused by a lessened ability or a complete inability to digest lactose, a sugar found in dairy products. Humans vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, flatulence, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking something containing lactose, with the severity typically depending on the amount consumed. Lactose intolerance does not cause damage to the gastrointestinal tract.

Lactose intolerance is due to the lack of the enzyme lactase in the small intestines to break lactose down into glucose and galactose. There are four types: primary, secondary, developmental, and congenital. Primary lactose intolerance occurs as the amount of lactase declines as people grow up. Secondary lactose intolerance is due to injury to the small intestine. Such injury could be the result of infection, celiac disease, inflammatory bowel disease, or other diseases. Developmental lactose intolerance may occur in premature babies and usually improves over a short period of time. Congenital lactose intolerance is an extremely rare genetic disorder in which little or no lactase is made from birth. The reduction of lactase production starts typically in late childhood or early adulthood, but prevalence increases with age.

A chronic condition (also known as chronic disease or chronic illness) is a health condition or disease that is persistent or otherwise long-lasting in its effects or a disease that comes with time. The term chronic is often applied when the course of the disease lasts for more than three months.

Common chronic diseases include diabetes, functional gastrointestinal disorder, eczema, arthritis, asthma, chronic obstructive pulmonary disease, autoimmune diseases, genetic disorders and some viral diseases such as hepatitis C and acquired immunodeficiency syndrome.

A cure is a substance or procedure that resolves a medical condition. This may include a medication, a surgical operation, a lifestyle change, or even a philosophical shift that alleviates a person's suffering or achieves a state of healing. The medical condition can be a disease, mental illness, genetic disorder, or a condition considered socially undesirable, such as baldness or insufficient breast tissue.

An incurable disease is not necessarily a terminal illness, and conversely, a curable illness can still be fatal.

A birth defect is an abnormal condition that is present at birth, regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders.

Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many birth defects are believed to involve multiple factors. Birth defects may be visible at birth or diagnosed by screening tests. A number of defects can be detected before birth by different prenatal tests.

Physical disorder, as a medical term, is poorly defined, and typically used in contrast to a mental disorder or a genetic disorder. The term mental disorder is heavily used in psychiatric medicine, and is defined in some psychiatric medicine texts, most notably the Diagnostic and Statistical Manual of Mental Disorders (DSM). However, the more generic term of medical disorder is poorly defined, and is not mentioned in the World Health Organization's International Classification of Diseases, nor many common medical textbooks. Attempts have been made to adopt a more universal definition, but there is no widely agreed upon definition.

A physical disorder is not easily defined as the term "disorder" itself has not yet been defined by any authoritative medical body. The term "disorder" bears no special clinical relevance, and could be used interchangeably with disease. The use of the term "disorder" likely rests on historical precedent as well as the preference of the field. For example, it is common to find examples of diseases named "disorders" in psychiatry and genetics, such as autosomal dominant disorders, but uncommon in cardiology. In general, diseases called "disorders" have a relatively well understood, narrow pathophysiology, such as bipolar disorder, compared to something more generic, such as heart disease. Similarly, disorders are typically not acquired, or the result of environmental factors, such as lung disease.