More than 350 conditions have been identified. They can differ greatly and result from a variety of causes. It is important that the type of restricted growth condition is identified as precisely as possible. Understanding the characteristics and the potential consequences of a particular type of restricted growth is more important than mastering the medical terminology which can be confusing. It is good to learn and understand both the general and particular effects a disorder is likely to have upon an individual.
Restricted growth can be inherited via genes and earlier forbears. Although they usually don’t have signs of any growth disorder, it can appear as a genetic accident at conception.
Some of the common types of restricted growth are:
Achondroplasia
This is by far the most common. The most obvious characteristic is the shortening of the limbs, particularly the upper arm and thigh. The skull is relatively large and the forehead prominent whilst the bridge of the nose does not properly develop. The hands and feet are short and broad with middle fingers the same length. The elbows do not usually extend fully. There are characteristic abnormalities of the base of the skull and spine which can lead to neurological problems, usually causing pain or numbness in the lower back and legs at middle age.
For more information click to the John Hopkins Library here
Hypochondroplasia
This is distinct from achondroplasia but is often confused with it as it merely seems a milder version. It is not very evident at birth but becomes noticeable as the child develops. The hands and feet are small but the skull is not affected. The spine has some of the same abnormalities as achondroplasia but individuals are less likely to suffer problems.
For more information click to the John Hopkins Library here
Multiple Epiphyseal Dysplasia
The growing points of the long bones are affected in this condition providing variable growth restrictions but sparing the spine. The most severe symptom of this condition is degeneration of the weight bearing joints which may require corrective surgery. In one particular type there may be problems with the skin, hair, gums and a tendency to develop cataracts.
For more information click to the John Hopkins Library here
Spondylo Epiphyseal Dysplasia
This is a condition where the growing ends of the bones and spine especially are affected. The two most common are SED Congentia which is apparent at birth and SED Tarda which has a later onset and is only seen in males. In SED Congentia the knees and hips are prone to deformity, the neck is short and the vertebrae weak at the base of the skull which may require fusion. In SED Tarda the main abnormality is in the spine which becomes very shortened and stiff. There is often mild curvature of the spine and hands may reach down to the knees.
For more information click to the John Hopkins Library here
Pseudoachondroplasia
This condition is similar to achondroplasia but facial features are unaffected and it is not readily recognisable at birth. Although spinal problems are rare, the loose joints experienced by some may result in wear and tear later on in life.
For more information click to the John Hopkins Library here
Pituitary
This is caused by hormone deficiency from the pituitary glands. This can be detected in children at about two years old and the earlier treatment is commenced the more likely the individual is to reach their full potential adult stature. It is the rate of growth rather than the short stature itself that is the important criteria. Treatment will involve regular injections of the lacking hormone.
There are another ninety conditions. These are very rare conditions giving rise to restricted growth. The following are some of the rarer types.
For more information click to the Australian Pituitary Foundation here
Metatropic Dwarfism or metatrophic dysplasia
The term metatropic means ‘changing form’ and dys (abnormal) plasia (growth). Accordingly metatropic means changing from short limb to short trunk after birth. At birth the dwarfism is more apparent in the limbs rather than the trunk. However, after a child has grown for several years, the shortening becomes much more apparent in the trunk.
For more information click to the John Hopkins Library here
Diastrophic dysplasia
In this condition the shortening affects the trunk and the limbs. It is evident at birth. It is usually associated with clubfoot, contractures of the hip, knees, elbows and hands. This condition can be serious and progressive, and cause the development of spinal curvature. Cleft palate occurs in some individuals. Tissues which in the normal person remain as cartilage in the adult, can develop nodules of bone (ossify). These tissues may include the outer ear, the bones of the inner area, the nose, the larynx, parts of the rib cage, and in time the joints of the fingers so that they will not bend. The skull is relatively normal but the neck is short and may show limited mobility. Sometimes the nerves of the spinal cord become compressed leading to numbness or pain.
For more information click to the John Hopkins Library here
Mucopolysaccharide diseases
These are a group of diseases where enzyme deficiencies result in the build up of unwanted chemicals in the tissues of the bones, cartilage, brain, blood vessels and heart, skin, etc. Most mucopolysaccharide diseases cause progressive physical and mental deterioration and early death. However, some are less life threatening, e.g. Morquio disease which usually results in severe short stature.
Morquio’s does not become apparent until the child is at least 18 months of age, the joints are very loose, and spinal curvature may occur as an early sign. They are of normal intellect and the chest protrudes as the ribs grow but the spine fails to maintain its growth rate. breathing problems often result and there are risks of oxygen starvation at high altitude. There also may be heart problems. Walking is difficult and often severe knock-knee deformities develop. A poorly developed pivot joint at the base of the skull causes a severe instability of the neck vertebrae. Fortunately, the neck is short and its mobility therefore limited but there can be severe consequences of loss of strength of limbs and paralysis which should be treated with special techniques of spinal fusion.
For more information click to the John Hopkins Library here
Other conditions of short stature
Cartilage Hair Hypoplasia
Ellis-van Creveld Syndrome
Osteogenesis Imperfecta
Turner Syndrome
For a more comprehensive list of conditions of short stature check the following link
LPA Medical Resource Center – Dwarfism Types & Diagnoses
(Source of text: Information Guide to Persons of Short Stature, edited by Stephen Pinnell, pp. 2-4)