dwarfism dwarfism dwarfism is a condition wherein an organism is exceptionally small, and mostly occurs in the animal kingdom. in humans, it is sometimes defined as an adult height of less than 147 centimetres (4 ft 10 in), regardless of sex; the average adult height among people with dwarfism is 122 centimetres (4 ft 0 in). disproportionate dwarfism is characterized by either short limbs or a short torso. in cases of proportionate dwarfism, both the limbs and torso are unusually small. intelligence is usually normal, and most have a nearly normal life expectancy. people with dwarfism can usually bear children, though there are additional risks to the mother and child dependent upon the underlying condition. dwarfisma man in columbus, indiana, with dwarfism caused by achondroplasiapronunciation/ˈdwɔːrfɪzəm/ specialtyendocrinology, medical geneticscauseshyposecretion of growth hormone from pituitary gland (growth hormone deficiency), genetic disorders the most common and recognisable form of dwarfism in humans (comprising 70% of cases) is achondroplasia, a genetic disorder whereby the limbs are diminutive. growth hormone deficiency is responsible for most other cases. there are also many other less common causes. treatment of the condition depends on the underlying cause. those with genetic disorders can sometimes be treated with surgery or physical therapy. hormone disorders can also be treated with growth hormone therapy before the child's growth plates fuse. individual accommodations, such as specialized furniture, are often used by people with dwarfism. many support groups provide services to aid individuals and the discrimination they may face. in addition to the medical aspect of the condition, there are also social aspects. for a person with dwarfism, height discrimination can lead to ridicule in childhood and discrimination in adulthood. in the united kingdom, united states, canada, australia, and other english-speaking countries, labels that some people with dwarfism accept include dwarf (plural: dwarfs), little person (lp), or person of short stature (see terminology). historically, the term midget was used to describe dwarfs (primarily proportionate); however, some now consider this term offensive. signs and symptoms dwarfism occurs in animals as well as humans; horses can have achondroplastic symptoms, as shown here next to a person with dwarfism. all small dog breeds exhibit dwarfism (the standard size of dogs, without interference from humans, is the same as that of the wolves). a defining characteristic of dwarfism is an adult height less than the 2.3rd percentile of the cdc standard growth charts. there is a wide range of physical characteristics. variations in individuals are identified by diagnosing and monitoring the underlying disorders. there may not be any complications outside adapting to their size. short stature is a common replacement of the term 'dwarfism', especially in a medical context. short stature is clinically defined as a height within the lowest 2.3% of those in the general population. however, those with mild skeletal dysplasias may not be affected by dwarfism. in some cases of untreated hypochondroplasia, males grow up to 165 cm (5 feet 5 inches). though that is short in a relative context, it does not fall into the extreme ranges of the growth charts. disproportionate dwarfism is characterized by shortened limbs or a shortened torso. in achondroplasia one has an average-sized trunk with short limbs and a larger forehead. facial features are often affected and individual body parts may have problems associated with them. spinal stenosis, ear infection, and hydrocephalus are common. in case of spinal dysostosis, one has a small trunk, with average-sized limbs. proportionate dwarfism is marked by a short torso with short limbs, thus leading to a height that is significantly below average. there may be long periods without any significant growth. sexual development is often delayed or impaired into adulthood. this dwarfism type is caused by an endocrine disorder and not a skeletal dysplasia. physical effects of malformed bones vary according to the specific disease. many involve joint pain caused by abnormal bone alignment, or from nerve compression. early degenerative joint disease, exaggerated lordosis or scoliosis, and constriction of spinal cord or nerve roots can cause pain and disability. reduced thoracic size can restrict lung growth and reduce pulmonary function. some forms of dwarfism are associated with disordered function of other organs, such as the brain or liver, sometimes severely enough to be more of an impairment than the unusual bone growth. mental effects also vary according to the specific underlying syndrome. in most cases of skeletal dysplasia, such as achondroplasia, mental function is not impaired. however, there are syndromes which can affect the cranial structure and growth of the brain, severely impairing mental capacity. unless the brain is directly affected by the underlying disorder, there is little to no chance of mental impairment that can be attributed to dwarfism. the psycho-social limitations of society may be more disabling than the physical symptoms, especially in childhood and adolescence, but people with dwarfism vary greatly in the degree to which social participation and emotional health are affected. social prejudice against extreme shortness may reduce social and marital opportunities. numerous studies have demonstrated reduced employment opportunities. severe shortness is associated with lower income. self-esteem may decline and family relationships may be affected. extreme shortness (in the 60–90 cm or 2–3 feet range) can, if not accommodated for, interfere with activities of daily living, like driving or using countertops built for taller people. other common attributes of dwarfism such as bowed knees and unusually short fingers can lead to back problems and difficulty in walking and handling objects. children with dwarfism are particularly vulnerable to teasing and ridicule from classmates. because dwarfism is relatively uncommon, children may feel isolated from their peers. causes seneb, court official and priest for the ancient egyptian rulers khufu and djedefre, with his wife senetites and their children dwarfism can result from many medical conditions, each with its own separate symptoms and causes. extreme shortness in humans with proportional body parts usually has a hormonal cause, such as growth-hormone deficiency, once called pituitary dwarfism. achondroplasia is responsible for the majority of human dwarfism cases, followed by spondyloepiphyseal dysplasia and diastrophic dysplasia. achondroplasia further information: achondroplasia the most recognizable and most common form of dwarfism in humans is achondroplasia, which accounts for 70% of dwarfism cases, and occurs in 4 to 15 out of 100,000 live births. it produces rhizomelic short limbs, increased spinal curvature, and distortion of skull growth. in achondroplasia the body's limbs are proportionately shorter than the trunk (abdominal area), with a larger head than average and characteristic facial features. achondroplasia is an autosomal dominant disorder caused by the presence of an altered allele in the genome. if a pair of achondroplasia alleles are present, the result is fatal. achondroplasia is a mutation in the fibroblast growth factor receptor 3. in the context of achondroplasia, this mutation causes fgfr3 to become constitutively active, inhibiting bone growth. growth hormone deficiency further information: growth hormone deficiency growth hormone deficiency (ghd) is a medical condition in which the body produces insufficient growth hormone. growth hormone, also called somatotropin, is a polypeptide hormone which stimulates growth and cell reproduction. if this hormone is lacking, stunted or even halted growth may become apparent. children with this disorder may grow slowly and puberty may be delayed by several years or indefinitely. growth hormone deficiency has no single definite cause. it can be caused by mutations of specific genes, damage to the pituitary gland, turner's syndrome, poor nutrition, or even stress (leading to psychogenic dwarfism). laron syndrome (growth hormone insensitivity) is another cause. those with growth hormone issues tend to be proportionate. metatropic dysplasia metatropic means "changing form" and refers to this form of skeletal dysplasia as there is an abnormality in the growth plates. skeletal changes continue over time and may need surgical intervention to help protect the lungs. symptoms starting at birth may be mild or can be fatal. there are recognizable features in individuals with this genetic disorder. some are short stature, narrow chest, " facial features such as a prominent forehead, underdevelopment of the upper jaw, cheekbones and eye sockets (midface hypoplasia), and a squared-off jaw." it is considered a more severe skeletal dysplasia, but is very rare, with the exact number of those affected unknown. prognosis is largely on a case-by-case basis depending on the severity, and life expectancy may not be impacted unless there are respiratory complications. other other causes of dwarfism are spondyloepiphyseal dysplasia congenita, diastrophic dysplasia, pseudoachondroplasia, hypochondroplasia, noonan syndrome, primordial dwarfism, cockayne syndrome, kniest dysplasia, turner syndrome, osteogenesis imperfecta (oi), and hypothyroidism. severe shortness with skeletal distortion also occurs in several of the mucopolysaccharidoses and other storage disorders. hypogonadotropic hypogonadism may cause proportionate, yet temporary, dwarfism. npr2 disproportionate dwarfism was discovered recently and is caused by a mutant gene. serious chronic illnesses may produce dwarfism as a side effect. harsh environmental conditions, such as malnutrition, may also produce dwarfism. these types of dwarfism are indirect consequences of the generally unhealthy or malnourished condition of the individual, and not of any specific disease. the dwarfism often takes the form of simple short stature, without any deformities, thus leading to proportionate dwarfism. in societies where poor nutrition is widespread, the average height of the population may be reduced below its genetic potential by the lack of proper nutrition. sometimes there is no definitive cause of short stature. diagnosis dwarfism is often diagnosed in childhood on the basis of visible symptoms. a physical examination can usually suffice to diagnose certain types of dwarfism, but genetic testing and diagnostic imaging may be used to determine the exact condition. in a person's youth, growth charts that track height can be used to diagnose subtle forms of dwarfism that have no other striking physical characteristics. short stature or stunted growth during youth is usually what brings the condition to medical attention. skeletal dysplasia is usually suspected because of obvious physical features (e.g., unusual configuration of face or shape of skull), because of an obviously affected parent, or because body measurements (arm span, upper to lower segment ratio) indicate disproportion. bone x-rays are often key to diagnosing a specific skeletal dysplasia, but are not the sole diagnostic tool. most children with suspected skeletal dysplasias are referred to a genetics clinic for diagnostic confirmation and genetic counseling. since about the year 2000, genetic tests for some of the specific disorders have become available. during an initial medical evaluation of shortness, the absence of disproportion and other clues listed above usually indicates causes other than bone dysplasias. classification lavinia warren, an actress with pituitary dwarfism (growth hormone deficiency) in men and women, the sole requirement for being considered a dwarf is having an adult height under 147 cm (4 ft 10 in) and it is almost always sub-classified with respect to the underlying condition that is the cause of the short stature. dwarfism is usually caused by a genetic variant; achondroplasia is caused by a mutation on chromosome 4. if dwarfism is caused by a medical disorder, the person is referred to by the underlying diagnosed disorder. disorders causing dwarfism are often classified by proportionality. disproportionate dwarfism describes disorders that cause unusual proportions of the body parts, while proportionate dwarfism results in a generally uniform stunting of the body. disorders that cause dwarfism may be classified according to one of hundreds of names, which are usually permutations of the following roots: location rhizomelic = root, i.e., bones of the upper arm or thigh mesomelic = middle, i.e., bones of the forearm or lower leg acromelic = end, i.e., bones of hands and feet. micromelic = entire limbs are shortened source chondro = of cartilage osteo = of bone spondylo = of the vertebrae plasia = form trophy = growth examples include achondroplasia and chondrodystrophy. prevention many types of dwarfism are currently impossible to prevent because they are genetically caused. genetic conditions that cause dwarfism may be identified with genetic testing, by screening for the specific variations that result in the condition. however, due to the number of causes of dwarfism, it may be impossible to determine definitively if a child will be born with dwarfism. dwarfism resulting from malnutrition or a hormonal abnormality may be treated with an appropriate diet or hormonal therapy. growth hormone deficiency may be remedied via injections of human growth hormone (hgh) during early life. management genetic mutations of most forms of dwarfism caused by bone dysplasia cannot be altered