Genetic factor

Genetic factors play an important role in the development of hypersensitivity to drugs. It has been claimed that patients with an atopic constitution are predisposed 

The rate of drug metabolism, which is in part under genetic control, may be of importance. The population with low levels of hepatic acetyltransferase activity seems at greater risk of developing the hydralazine-induced lupus syndrome (Perry et al. 1970), but this does not hold for procainamide-induced lupus. Genetic factors have also been implied in pseudoallergic reactions, such as aspirin intolerance (Lockey et al. 1963). 

Not all organisms including humans react in the same way to a given dose of a chemical or an environmental pollutant. In experimental animals, species variation as well as variation in strains within the same species occur. In humans, such factors as serum, red blood cell, immunological disorders, and malabsorption can contribute to differences in their response to environmental stresses. For instance, people with sickle cell anemia will be more susceptible to stresses than normal persons. Individuals with malab-sorptive disorders are also a problem since they may suffer nutritional deficiencies, which in turn may lead to an increased susceptibility to environmental chemicals. 

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The distribution between LDL and HDL choles terol depends mainly on genetic factors but can be... 

Several aspects affect the extent and character of taste and smell. People differ considerably in sensitivity and appreciation of smell and taste, and there is lack of a common language to describe smell and taste experiences. A hereditary or genetic factor may cause a variation between individual reactions, eg, phenylthiourea causes a bitter taste sensation which may not be perceptible to certain people whose general abiUty to distinguish other tastes is not noticeably impaired (17). The variation of pH in saUva, which acts as a buffer and the charge carrier for the depolarization of the taste cell, may influence the perception of acidity differently in people (15,18). Enzymes in saUva can cause rapid chemical changes in basic food ingredients, such as proteins and carbohydrates, with variable effects on the individual. 

Whatever the physiology of odor perception may be, the sense of smell is keener than that of taste (22). If flavors are classed into odors and tastes as is common practice in science, it can be calculated that there are probably more than 10 possible sensations of odor and only a few, perhaps five, sensations of taste (13,21,35—37). Just as a hereditary or genetic factor may cause taste variations between individuals toward phenylthiourea, a similar factor may be in operation with odor. The odor of the steroid androsterone, found in many foods and human sweat, may eflcit different responses from different individuals. Some are very sensitive to it and find it unpleasant. To others, who are less sensitive to it, it has a musk or sandalwood-like smell. Approximately 50% of the adults tested cannot detect any odor even at extremely high concentrations. It is befleved that this abiUty is genetically determined (38). 

Sodium and Hypertension. Salt-free or low salt diets often are prescribed for hypertensive patients (57). However, sodium chloride increases the blood pressure in some individuals but not in others. Conversely, restriction of dietary NaCl lowers the blood pressure of some hypertensives, but not of others. Genetic factors and other nutrients, eg, Ca " and K", may be involved. The optimal intakes of Na" and K" remain to be estabUshed... 

Breast Cancer. Many studies have observed low incidences of hormone-dependent cancers, particularly breast cancer, in Asian countries compared with Western countries and it is becoming increasingly accepted that dietary factors play an important role. Although breast cancer can occur in either males or females, only about 1 % of all cases occur in men, and male breast cancer is a rare disease in all parts of the world." Although there appear to be some similar risk factors for breast cancer in males and females, there is no indication in the literature that diet is either a risk or a protective factor for male breast cancer. The development of breast cancer is known to be highly dependent on the hormones associated with female reproductive functions, while established genetic factors have been... 

An idiosyncratic reaction is a harmful, sometimes fatal reaction, that occurs in a small minority of individuals. The reaction may occur with low doses of drags. Genetic factors may be responsible, e.g. glucose-6-phosphate dehydrogenase deficiency, although the cause is often poorly understood. 

Rheumatoid arthritis (RA) is a chronic inflammatory disease of unknown aetiology with some autoimmune features. Current thinking favours the hypothesis that interplay between genetic factors, sex hormones, and possibly an infectious agent or another immune activating agent initiates an autoimmune pathogenic mechanism that culminates in a disease with inflammatory and destructive features. 

Some modern varieties of cereals such as wheat and rice achieve high yield potential through genetic factors for plant dwarfness that improve harvest index. A popular notion among plant breeders is that high-yielding... 

Susceptibility to acne is also due to genetic factors. It does not follow Mendelian rules however, if both parents had severe acne when adolescents, their children are likely to present with clinical acne in puberty. Genetic factors play an important role in determining the size and the activity of sebaceous glands, while exogenous factors such as colonization of P acnes modulate the clinical expression of acne. Racial differences also exist. Caucasians are more prone to severe acne than black people. 

Various factors affect the activities of the enzymes metabolizing xenobiotics. The activities of these enzymes may differ substantially among species. Thus, for example, the possible toxicity or carcinogenicity of xenobiotics cannot be extrapolated freely from one species to another. There are significant differences in enzyme activities among individuals, many of which appear to be due to genetic factors. The activities of some of these enzymes vary according to age and sex. 

A number of factors described as influencing carotenoid bioavailability were regrouped under the SLAMENGFll mnemonic. Species of carotenoid. Linkages at molecular level. Amount of carotenoids consumed in a meal. Matrix in which the carotenoid is incorporated. Effectors of absorption and bioconversion. Nutrient status of the host. Genetic factors. Host-related factors, and Interactions among these variables. Only the factors that affect the micellarization of the compound in the gut are discussed and summarized in Table 3.2.1. 

Fanciullino, A.-L. et ah. Carotenoid diversity in cultivated citrus is highly influenced by genetic factors, J. Agric. Food Chem., 54, 4397, 2006. 

Sillitoe, R.H. (1993) Giant and bonanza gold deposits in the epithermal environment Assessment of potential genetic factors. In Whiting, Mason, B.H. and Hodgson, C.H. (eds.). Giant Ore Deposits. Soc. Econ. Geol. Special Pub., 2, 125-156. 

Genetic factors cannot explain the recent rapid rise in asthma prevalence. Asthma appears to require both genetic predisposition and environmental exposure. Many patients with occupational asthma develop the disease late in life upon exposure to specific allergens in the workplace. Environmental influences in utero or in infancy may contribute to the development of asthma. Maternal smoking during pregnancy or exposure to secondhand smoke after birth increases the risk of childhood asthma.3 Adult-onset asthma is not uncommon and may be related to atopy, nasal polyps, aspirin sensitivity, occupational exposure, or a recurrence of childhood asthma. 

Psoriasis is a T-lymphocyte-mediated inflammatory disease that results from a complex interplay between multiple genetic factors and environmental influences. Genetic predisposition coupled with some precipitating factor triggers an abnormal immune response, resulting in the initial psoriatic skin lesions. Keratinocyte proliferation is central to the clinical presentation of psoriasis. 

The etiology of breast cancer is unknown, but a number of factors that increase a woman s chances of developing the disease have been identified. These risk factors, as well as information regarding the biology of the disease, suggest that a complex interplay between hormones, genetic factors, and environmental and lifestyle influences all contribute to the etiology of this disease. 

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