disproportionate dwarfism


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dis·pro·por·tion·ate dwarf·ism

dwarfism characterized by more significant shortening of the limbs or the trunk; when the limbs are primarily involved, the shortening may predominate in the proximal segments (rhizomelia), middle segments (mesomelia), or distal segments (acromelia); usually results from hereditary intrinsic skeletal dysplasias.

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
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.
Enlarge picture
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.