Different causes of growth disorders include genetic conditions, hormonal disorders, poor absorption of food, or systemic diseases. These causes usually fall into one of the following categories:
Familial short stature. Familial short stature is a tendency to follow the family's pattern of inherited short stature (shortness).
Familial tall stature. Some children may be taller than average for their age if their parents are tall. This is called familial tall stature. Some children may be tall as a result of precocious puberty, the early onset of adolescence. Precocious puberty often causes rapid growth and tall stature compared with a child’s peers. However, because of rapid and premature maturation of growth plates in the bones, growth stops at an early age. As a result, children with precocious puberty may be short as adults. A few rare conditions can result in tall stature and also cause health problems.
Constitutional delay of growth and pubertal development. With a constitutional growth delay, a child tends to be shorter than average and to enter puberty later than average, while growing at a normal rate. Constitutional growth delay may be inherited. These children tend to eventually catch up and reach their normal adult height.
Illnesses that affect the whole body (also called systemic diseases). Constant malnutrition, digestive tract diseases, kidney disease, heart disease, lung disease, diabetes, or chronic severe stress can cause growth problems.
Endocrine (hormone) diseases. Growth can be affected by several different conditions that disrupt hormone production. Adequate production of the thyroid hormone is essential for normal bone growth. The pituitary gland at the base of the brain secretes several hormones, including growth hormone. Growth hormone deficiency can result from injuries to the pituitary gland or brain. Cushing's syndrome, a rare condition caused by hypersecretion of corticosteroids by an adrenal gland, can impair growth.
Congenital (present at birth) problems in the tissues where growth occurs. With a condition called intrauterine growth restriction (IUGR), slow fetal growth within the uterus occurs during a pregnancy. This can be caused by many factors, such as smoking during pregnancy or inadequate prenatal care. The baby is born smaller in weight and length than normal, although proportionate to his/her short stature.
Turner syndrome. Having too many, too few, or disrupted chromosomes can result in health problems. Turner syndrome is a common genetic disorder, affecting only girls, that causes poor growth and delayed or absent puberty. Turner syndrome occurs in 1 in 2,500 females born and results from missing one X chromosome. Other health problems may also be present involving the heart, kidneys, or other parts of the body. The severity of these problems varies among affected individuals.
Down syndrome. Down syndrome is another common genetic disorder causing poor growth and short stature. It results from an extra 21st chromosome.
Achondroplasia. The most common genetic bone disease is achondroplasia, in which the child’s arms and legs are short in proportion to his or her body length. Further, the head is often large and the trunk is normal size.
Many conditions can be managed or corrected by medical treatment. Most disorders causing poor growth or short stature are idiopathic and lack any recognizable cause.
Some growth problems may be immediately diagnosed at birth, because the infant may be abnormally small for his or her gestational age. Most growth problems are noticed when the child appears smaller than his or her classmates, or when growth lags over several month. One primary symptom that may indicate a growth problem is when a child grows less than 3.5 cm (about 1.4 inches) a year after his or her third birthday. Growth problems may mask other problems or medical conditions. Always consult your child's doctor for a diagnosis.
Diagnosis of a growth disorder must be made by your child's doctor, often in consultation with a pediatric subspecialist. The method used for diagnosis will depend on the type of growth disorder presented. In addition to a complete medical history and physical exam, diagnostic tests may include:
Observing your child's health and growth over several months
Blood tests to rule out hormone, chromosomal, or other disorders associated with growth failure
X-ray of the bones (usually of the left hand and wrist). This uses a small amount of radiation to create pictures of bones and other tissues. An X-ray image of the hand can estimate your child’s “bone age.” With delayed puberty or hormone deficiencies, bone age is often delayed relative to calendar age.
Examining the functions of the pituitary gland, which produces and secretes growth hormone and other important hormones
Specific treatment for growth problems will be determined by your child's doctor. Plans will be based on:
Your child's current health status and health history
Severity of the problem
Your child's ability to deal with medical procedures and take prescribed medicines
Your beliefs and desires regarding treatment
Treatment and outcomes of growth problems will depend on the underlying cause.