rhizomelic dwarfism


dwarfism

 [dwor´fizm] underdevelopment of the body; the state of being a dwarf" >dwarf. It may be the result of a anomaly" >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" >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.achondroplastic dwarfism dwarfism due to achondroplasia" >achondroplasia; see dwarfism.pituitary dwarfism dwarfism due to inadequate secretion of hormone" >growth hormone by the pituitary gland" >pituitary gland; see dwarfism" >dwarfism.renal dwarfism dwarfism caused by renal failure" >renal failure.rhizomelic dwarfism the autosomal recessive form of chondrodysplasia punctata.

rhizomelic dwarfism

one of the syndromes of chondrodysplasia punctata (q.v.), autosomal recessive, with variable skin keratinization disorders and variable facial, cardiac, optic, and central nervous system abnormalities; epiphysial stippling is also present. There are multiple enzymatic defects, including peroxisomal types, and affected infants fail to thrive and usually die in infancy.

rhi·zo·mel·ic dwarf·ism

(rī'zō-mel'ik dwōrf'izm) One of the syndromes of chondrodysplasia punctata; autosomal recessive, with variable skin keratinization disorders and variable facial, cardiac, optic, and central nervous system abnormalities; epiphysial stippling is also present. There are multiple enzymatic defects, including peroxisomal ones, and affected infants fail to thrive and usually die in infancy.