Short Stature

Short stature refers to a height of a human which is below typical. Whether a person is considered short depends on the context. Because of the lack of preciseness, there is often disagreement about the degree of shortness that should be called short.

In a medical context, short stature is typically defined as an adult height that is more than two standard deviations below a population’s mean for age and gender, which corresponds to the shortest 2.3% of individuals in that population. The median or typical adult height in developed countries (as the widely abundant statistics from these countries clearly state) is about 179 centimetres (5 ft 10 in) for men and 166 centimetres (5 ft 5 in) for women.

Causes

Shortness in children and young adults nearly always results from below-average growth in childhood, while shortness in older adults usually results from loss of height due to kyphosis of the spine or collapsed vertebrae from osteoporosis. The most common causes of short stature in childhood are constitutional growth delay or familial short stature.

From a medical perspective, severe shortness can be a variation of normal, resulting from the interplay of multiple familial genes. It can also be due to one or more of many abnormal conditions, such as chronic (prolonged) growth hormone or thyroid hormone deficiency, malnutrition, disease of a major organ system, mistreatment, treatment with certain drugs, chromosomal deletions. Human growth hormone (HGH) deficiency may occur at any time during infancy or childhood, with the most obvious sign being a noticeable slowing of growth. The deficiency may be genetic. Among children without growth hormone deficiency, short stature may be caused by Turner syndrome or Noonan syndrome, chronic kidney disease, being small for gestational age at birth, Prader–Willi syndrome, Wiedemann-Steiner syndrome, or other conditions. Genetic skeletal dysplasias also known as osteochondrodysplasia usually manifest in short-limbed disproportionate short stature.

When the cause is unknown, it is called idiopathic short stature. Short stature can also be caused by the bone plates fusing at an earlier age than normal, therefore stunting growth. Normally, the bone age is the same as the biological age but for some people, it is older. For many people with advanced bone ages, they hit a growth spurt early on which propels them to average height but stop growing at an earlier age. However, in some cases, people who are naturally shorter combined with their advanced bone age, end up being even shorter than the height they normally would have been because of their stunted growth.

Classification

Chronic illnesses, malnutrition, endocrine, metabolic disorders or chromosomal anomalies are characterized by proportionate short stature. On the other hand, most genetic skeletal dysplasias are known for short stature that may be proportionate or disproportionate. Disproportionate short stature can be further subdivided as specified by the body segments affected by shortening, namely limbs versus trunk:

• Short-limb short stature in which there is limb shortening as achondroplasia, hypochondroplasia, pseudoachondroplasia and multiple epiphyseal dysplasia.
• Short-trunk short stature in which there is trunk shortening as spondyloepiphyseal dysplasia and mucopolysaccharidosis

Short-limb short stature can be further subcategorised in accordance with limb segment affected by shortening. These subcategories of limb shortening include, rhizomelic (humerus and femur), mesomelic (radius, ulna, tibia and fibula) and acromelic (hands and feet). Anthropometric measurements provide are very beneficial tools to the diagnostic process of genetic skeletal dysplasias. The anthropometric measurements include height, sitting height, arm span, upper/ lower-body segment ratio, sitting height/height ratio, and arm span/height ratio for age. They also aid in the differential diagnosis of skeletal dysplasia subtypes.

History

During World War I in Britain, the minimum height for soldiers was 5 feet 3 inches (160 cm). Thus thousands of men under this height were denied the opportunity to fight in the war. As a result of pressure to allow them entry, special "Bantam Battalions" were created composed of men who were 4 feet 10 inches (147 cm) to 5 feet 3 inches (160 cm). By the end of the war there were 29 Bantam Battalions of about 1,000 men each. Officers were of normal size.