Early Signs of Dwarfism

Dwarfism refers to a condition of extreme small size of a person, animal, or plant. Any type of marked human smallness could be termed dwarfism in older popular and medical usage. Currently, in both general and technical usage, the term as related to human beings (the major subject of this article) is restricted to those forms of extreme shortness characterized by disproportion of body parts, typically due to an inheritable disorder in bone or cartilage development.

In contrast, those forms of shortness characterized by proportional body parts usually have a hormonal or nutritional cause. An example is growth hormone deficiency, which was once called "Pituitary dwarfism". According to current usage, proportional shortness, even when severe, is no longer referred to as "dwarfism".

Types of dwarfism
Types of dwarfism are often clinically distinguished by the predominant segment of the limbs that is short:

rhizomelic = root, e.g. bones of upper arm or thigh
mesomelic = middle, e.g. bones of forearm or lower leg
acromelic = end, e.g. bones of hands and feet.
When the cause of dwarfism is understood, it may be classified according to one of hundreds of names, which are usually permutations of the following roots:

chondro = of cartilage
osteo = of bone
spondylo = of the vertebrae
plasia = form
trophy = growth
Examples include achondroplasia, osseous dysplasia, chondrodystrophy, and osteochondrodystrophy.

The most recognizable and most common form of dwarfism is achondroplasia, which produces rhizomelic short limbs, increased spinal curvature, and distortion of skull growth. It accounts for 70% of dwarfism cases. Other relatively common types include spondyloepiphyseal dysplasia congenita (SED), diastrophic dysplasia, pseudoachondroplasia, hypochondroplasia, and osteogenesis imperfecta (OI). Severe shortness with skeletal distortion also occurs in several of the mucopolysaccharidoses and other storage diseases.

The average adult height of male and female dwarfism sufferers are 132cm and 123cm respectively.

Genetics
Dwarfism is an autosomal dominant genetic disease effecting a single gene. The allele D is dominant for dwarfism over allele d for normal whereby:

dd = Normal
Dd = Dwarf
DD = Lethal
Those with DD will therefore die in the womb. Unusually for an autosomal dominant disease, 86% of dwarfs have normal parents and acquire the disease due to a de novo mutation, in the same base pair, in the gene encoding fibroblast growth factor receptor 3. This reduces the effect of growth hormones on fibroblasts and, therefore, cartilage growth is severely reduced, giving the characteristic disproportional size of limbs, particularly at proximal sites, for those suffering from dwarfism.

IQ and life expectancy are not effected by this condition and dwarfs are fertile.

Diagnosis
Unusually short stature for a child's age is usually what brings the child to medical attention. Skeletal dysplasia ("dwarfism") 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 the key to diagnosis of a specific skeletal dysplasia, but they are not the key diagnosis. Most children with suspected skeletal dysplasias will be referred to a genetics clinic for diagnostic confirmation and genetic counselling. (See External links, below, for a list of American referral centers with special expertise in skeletal dysplasias.) In the last decade, genetic tests for some of the specific disorders have become available.

During the initial medical evaluation for shortness, the absence of disproportion and the other clues above usually indicates other causes than bone dysplasias. Extreme shortness with completely normal proportions sometimes indicates growth hormone deficiency (pituitary dwarfism).

Short stature alone, in the absence of any other abnormalities, may simply be genetic, particularly if a person is born into a family of people who are relatively short.


Problems associated with dwarfism
The principal adverse effects of dwarfism can be divided into the physical and the social.

Physical effects of malformed bones vary according to the specific disease. Many involve pain resulting from joint damage from abnormal bone alignment, or from nerve compression (e.g, spinal stenosis). 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 disabling than the abnormal bone growth.

The psychosocial disadvantages may be more distressing 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 be reduced and family relationships affected
Extreme shortness (in the low 2–3 foot [60–90 cm] range) can interfere with ordinary activities of daily living, like driving or even using countertops built for taller people.

Treatment and support
As the genetic defects of most forms of dwarfism due to bone dysplasia cannot be corrected, therapeutic interventions are typically aimed at (1) preventing or reducing pain or physical disability, (2) increasing adult height, or (3) mitigating psychosocial stresses and enhancing social adaptation.

Pain and disability may be ameliorated by physical therapy, by braces or other orthotic devices, or by surgical procedures.

The only simple interventions that increase perceived adult height are dress enhancements such as shoe lifts or hairstyle. Growth hormone is rarely used for shortness due to bone dysplasias, as the height benefit is typically small (less than 5 cm) and the cost high. The most effective means of increasing adult height by several inches is limb-lengthening surgery, though availability is limited and cost is high in terms of dollars, discomfort, and interruption of life. Most people with dwarfism do not avail themselves of this, and it remains controversial. For other types of dwarfism, surgical treatment is not possible.

Early Signs of Dwarfism