dwarfism /dwarf·ism/ (dworf´izm) the state of being a dwarf.
Dwarfism, pituitary
dwarfism
dwarfism [dwor´fizm]
dwarfism,
dwarfism
dwarf·ism (dwôr f z  m)n. A pathological condition of arrested growth having various causes. Also called nanism. |
Dwarfism, pituitary
Short stature. When caused by inadequate amounts of growth hormone (as opposed to late growth spurt or genetics), hGH deficiency results in abnormally slow growth and short stature with normal proportions.
Mentioned in: Growth Hormone Tests, Kyphosis
dwarfism
[dwôrf′izəm]
the abnormal underdevelopment of the body, characterized predominantly by extreme shortness of stature, although the condition is associated with numerous other defects and may involve varying degrees of mental retardation. Dwarfism has multiple causes, including genetic defects, endocrine dysfunction involving either the pituitary or the thyroid gland, chronic diseases such as rickets, renal failure, intestinal malabsorption defects, and psychosocial stress, as in the maternal deprivation syndrome. See also dwarf.
dwarfism [dwor´fizm]
underdevelopment of the body; the state of being a dwarf. It may be the result of a developmental anomaly, of nutritional or hormone deficiencies, or of other diseases. The size of pygmies found in some parts of the world, such as the Philippines and equatorial Africa, is not the result of dwarfism; their small stature is a hereditary trait. Called also nanism and nanosomia.
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 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, 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 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.
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 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, 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 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.
achondroplastic dwarfism dwarfism due to achondroplasia; see dwarfism.
pituitary dwarfism dwarfism due to inadequate secretion of growth hormone by the pituitary gland; see dwarfism.
renal dwarfism dwarfism caused by renal failure.
rhizomelic dwarfism the autosomal recessive form of chondrodysplasia punctata.
dwarfism,
n deficient growth and development leading to small stature and often skeletal deformity. It may be associated with ovarian agenesis, pituitary insufficiency, mongolism, progeria, rickets, renal disease, dietary deficiency, achondroplasia, cleidocranial dysostosis, osteogenesis imperfecta, microcephaly, hydrocephaly, sexual precocity, and delayed adolescence.
dwarfism
the state of being a dwarf; underdevelopment of the body. Dwarfism may be the result of a developmental anomaly, of nutritional or hormone deficiencies, or of other diseases. See also achondroplasia, cretinism.
achondroplastic dwarfism
an inherited defect in cattle caused by defective cartilage growth which is effectively lethal because the calves do not grow well and die before 6 months of age. Typical signs are short legs, large, wide, short head, protruding lower jaw, depression of the maxilla with obstruction of respiration and stertorous breathing. The tongue protrudes and the eyes bulge, the abdomen is distended and there is chronic bloat. Urine levels of glycosaminoglycans are much higher than normal in some of the calves. Called also snorter dwarfs. The condition has also been seen in dogs and cats.
chondrodystrophic dwarfism with hydrocephalus
see bulldog calves.
constitutional dwarfism
a proportional dwarfism due to a generalized genetic defect.
disproportionate dwarfism
the skeleton is dystrophic, the soft tissues are normal. The animal is pot-bellied, dyspneic and the tongue protrudes. Characteristic of achondroplastic and chondrodystrophic dwarfs.
German shepherd dog dwarfism
an inherited juvenile panhypopituitarism caused by a defect in differentiation of the oropharyngeal ectoderm of Rathke's pouch. Affected puppies appear normal at birth but soon show a reduced rate of growth, retention of deciduous teeth and puppy hair, alopecia, delayed closure of epiphyseal growth plates, infantile genitalia and shortened life span. 
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A 6-month-old dwarf German shepherd dog.By permission from Ettinger SJ, Feldman E, Textbook ofVeterinary Internal Medicine, Saunders, 2004
pituitary dwarfism
see German shepherd dog dwarfism (above).
primordial dwarfism
general proportional dwarfism of all organs of the kind that has produced Kerry cattle and Miniature pinschers.
proportional dwarfism
primordial dwarfism (above).
thyroid dwarfism
hypothyroidism in an immature animal causes retarded growth and development of bones with disproportionate dwarfism. See cretinism.
dwarfism
Nanosomia 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.
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