dwarfism
dwarf·ism
D0440400 (dwôr′fĭz′əm)dwarfism
(ˈdwɔːfɪzəm) ordwarfness
dwarf•ism
(ˈdwɔr fɪz əm)n.
dwarf·ism
(dwôr′fĭz′əm)dwarfism
| Noun | 1. | dwarfism - a genetic abnormality resulting in short stature |
| 单词 | dwarfism | |||
| 释义 | dwarfismdwarf·ismD0440400 (dwôr′fĭz′əm)dwarfism(ˈdwɔːfɪzəm) ordwarfnessdwarf•ism(ˈdwɔr fɪz əm)n. dwarf·ism(dwôr′fĭz′əm)dwarfism
dwarfismdwarfism,condition in which an animal or plant is less than normal in size and lacks the capacity for normal growth. Dwarfism is deliberately produced and perpetuated in certain species (e.g., in breeding miniature dogs and cultivating dwarf plants). Among humans, dwarfism usually results from a combination of genetic factors and endocrine malfunction. It can also be caused, however, by acquired conditions, such as kidney disease. Pituitary dwarfism is caused by an insufficiency of the pituitary growth hormonegrowth hormoneor somatotropin , glycoprotein hormone released by the anterior pituitary gland that is necessary for normal skeletal growth in humans (see protein). ..... Click the link for more information. (hypopituitary dwarfism). Typically, the pituitary dwarf stops growing in early childhood but retains normal body proportion, mental capacity, and sexual development. Pharmaceutical companies are cloning human growth hormone to stimulate growth in children afflicted with hypopituitary glands. This type of dwarf, who is completely normal except for size, is commonly called a midget. Cretinismcretinism , condition produced in infants and children due to lack of thyroid hormone. It usually results from a congenital defect (e.g., absence of the thyroid, presence of only a rudimentary gland, inability of the gland to produce thyroxine). ..... Click the link for more information. is a type of dwarfism accompanied by mental retardation and distortion of the body, resulting from an insufficiency of thyroid hormone. Unlike cretinism and pituitary dwarfism (which are thought to be caused by a combination of heredity and endocrine malfunction), achondroplastic dwarfism is the result of a completely hereditary, dominant genetic trait. Typically, the growth of the limbs is stunted, but the size of the trunk and mental capacity are normal. Humans who range in height from 2 to 4 ft (5.08–10.16 cm) are generally classified as dwarfs. However, small size that is an inherited characteristic of race (such as among African Pygmies) is not considered to be dwarfism since the individuals in such groups are physiologically normal. Dwarfismnanism, abnormal shortness (less than 130 cm for males and less than 120 cm for females). The commonest cause of dwarfism is endocrine pathology. Dwarfism can be divided arbitrarily into proportional and dis-proportional (normal and achondroplastic) types. The former group includes pituitary, thyrogenic (cretin), and infantile dwarfism and dwarfism caused by brain disease, such as encephalitis and hydrocephaly. In pituitary dwarfism, which is caused by affection of the anterior lobe of the hypophysis (or the parts of the hypothalamus that regulate pituitary function) by tumor, infection, poisoning, or injury, the dwarf is almost normal mentally but the bodily proportions and size are those of a child, the gonads are underdeveloped, obesity is common, and the facial skin is wrinkled and senile. Thyrogenic (cretin) dwarfism, caused by affection of the thyroid gland, is accompanied by impairment of ossification, metabolic disturbances, dryness of skin, and mental retardation. Types of the disproportional category include rachitic dwarfism, caused by marked skeletal deformity, dwarfism in chondrodystrophy (congenital abnormality in cartilage formation), and dwarfism in systemic bone diseases. Treatment (before body growth ceases) is aimed at eliminatingthe causes of the dwarfism; this sometimes involves substitutiontherapy. Dwarfism is characteristic of certain tribes in Africa(Pygmies), Asia, and Oceania. dwarfism[′dwȯr‚fiz·əm]Dwarfismdwarfismdwarfism[dwor´fizm]A dwarf in adulthood may be as small as 75 cm (30 inches) tall. The proportions of body to head and limbs may be normal or abnormal. In certain conditions the body may be deformed or the person may suffer from mental retardation. achondroplasia" >achondroplasia is a developmental anomaly that affects the growth of the bones. The person's trunk is usually normal, but the head is unusually large and the limbs unusually small. Most fetuses with achondroplastic dwarfism are stillborn. Those who reach adulthood do not suffer lessening of their mental or sexual abilities, and may have unusual muscular strength. The condition does not significantly shorten the life span. An infant who suffers from an insufficiency of thyroxine" >thyroxine, a hormone secreted by the thyroid gland, may develop the symptoms of cretinism, including an enlarged head, short limbs, puffy eyes, a thick and protruding tongue, dry skin, and lack of coordination. This can be treated by giving the patient an extract of thyroxine; early treatment can result in normal growth and development. If the condition is not treated, however, the child will grow up dwarfed, mentally retarded, and sexually sterile. Pituitary dwarfism occurs when the pituitary gland does not produce enough hormone" >growth hormone. This hormone plays a major role in growth of the skeleton and viscera; if it is not produced in large enough quantities, growth of the trunk will be curtailed, and the head and limbs will be in normal proportion to the small torso. Administration of purified human growth hormone has been shown to induce skeletal growth in these patients. dwarf·ism(dwōrf'izm), Negative of pejorative connotations of this word may render it offensive in some contexts.dwarfism(dwôr′fĭz′əm)dwarfismNanosomia Excessively short stature–eg, ≤ 152 cm/5 ft in ♂ and ≤ 145 cm/4'9” in ♀; 35% of dwarfism is familial, 25% is idiopathic, 10% is due to pituitary failure, 10% to hypothyroidism, 10% to congenital gonadal aplasia, and the rest, etc; proper classification of the more than 55 congenital conditions associated with dwarfism allows determination of the likelihood of conceiving a similarly afflicted child. See Bird-headed dwarfism, Pituitary dwarfism, Psychosocial dwarfism, Silver-Russell dwarfism, Thanatophoric dwarfism.dwarf·ism(dwōrf'izm)dwarfismAbnormal shortness of stature. This may be of genetic origin as in ACHONDROPLASIA, DOWN'S SYNDROME, Trisomy 18, TURNER'S SYNDROME and Bloom's syndrome or it may result from glandular defects such as pituitary growth hormone deficiency, primary thyroid deficiency (CRETINISM), precocious puberty or adrenal gland insufficiency. It also results from various metabolic disorders such as HURLER'S SYNDROME, TAY-SACH'S DISEASE, NIEMANN-PICK DISEASE and GAUCHER'S DISEASE.dwarfisma form of body malfunction in which the adult individual does not reach the normal height and may sometimes have other abnormalities. Such conditions can be due to a deficiency of GROWTH HORMONE secreted by the anterior pituitary, or to cartilage abnormalities due to genetical defects (see ACHONDROPLASIA). Compare GIGANTISM.Dwarfism, pituitarydwarf·ism(dwōrf'izm)dwarfism
Synonyms for dwarfism
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