Fairy tales are filled with stories of giants and little people. The stories were written hundreds of years ago, and they sometimes tried to explain why these people looked different from others around them.

These old-fashioned fairy tales might have been different if the writers had known what today's doctors have learned about growth.

What's a Growth Disorder?

Everyone grows and matures differently. You may be taller than your best friend in fourth grade. But then in sixth grade, your best friend may be an inch taller than you. Usually, this is totally normal.

A growth disorder, however, means that a kid has abnormal growth — for example, growing a lot slower or a lot faster than other kids the same age.

What's Normal Growth?

If growth isn't the same for all kids, how do doctors know what's normal? By feet and inches (or meters and centimeters)! Over the years, lots of height and weight measurements have been taken for lots of children of different ages. These measurements have been put together in what is called a standard growth chart, which tells doctors about how most kids grow.

From the time you were a baby, your doctor has weighed and measured you whenever you've had a checkup. Because kids grow differently, your doctor checks your height against the standard growth chart. If you are in the 50th percentile on the growth chart, it means half of the kids your age are taller than you are and half are shorter. If you fall in the 25th percentile that means 75% of the kids your age are taller and 25% are shorter, and so on.

Most kids whose heights are between the 3rd percentile and the 97th percentile and who are growing at a steady rate are considered to have normal growth. Kids who are higher or lower than this on the growth chart are usually normal, too.

But some children who are under the 3rd percentile or over the 97th percentile, or who are growing a lot slower or faster than most other kids, may have a growth problem. In this situation, the doctor will usually want to check things out.

One thing your doctor will want to know is how tall your mother and father are and how they grew when they were children. You may have inherited short or tall genes from them. You may also have inherited the tendency to have your growth spurt earlier or later than most other kids do.

Problems With Puberty

Glands in your body produce chemical messengers called hormones. Normal increases in the amounts of some of these hormones being produced trigger the changes your body goes through during puberty.

Puberty is the stage of your life when sexual development happens, like breast development and menstrual periods in girls and growth of the penis and testicles in boys. One of the body changes that happens during puberty is a big increase in your rate of growth — a growth spurt. The higher levels of hormones in your body tell your bones to grow, grow, grow!

When these changes happen before the age of 8 in girls or 9 in boys, it's called precocious (say: prih-ko-shess), or early, puberty. At first, these kids may be taller than their friends. Later, however, they may stop growing sooner than most other kids do, and they may not become as tall when they're adults as they might have been otherwise. Usually, kids with precocious puberty can be treated with medications that help correct this problem.

Delayed or late puberty occurs when the hormonal and body changes that should happen with puberty take place later than normal, or sometimes not at all. Girls who have not begun puberty by age 13 and boys who have not begun by age 15 have delayed puberty and are sometimes called late bloomers. When puberty finally occurs, either by itself or with treatment, these teens have a growth spurt and tend to catch up to their peers. Sometimes they even grow to be taller than their friends!

Hormones and Growth Disorders

One of the glands in your body is called the pituitary gland (say: pih-too-ih-tare-ee). It's found at the bottom of your brain and is shaped like a peanut. It may be small in size, but it's pretty big in importance. One of the chemical messengers the pituitary gland sends out to your body is called growth hormone, which (no surprise) is essential for growth.

When the pituitary gland doesn't make enough growth hormone — and sometimes other pituitary hormones as well — the condition is called hypopituitarism (say: hy-po-peh-too-eh-ter-is-em). This can slow down a kid's growth. Special tests can find out if kids don't produce enough growth hormone. If they don't, daily shots of growth hormone can often help them grow to be normal-sized adults.

Another gland that produces hormones important for growth is your thyroid (say: thy-royd). You may be able to feel it if you press gently with your fingers across the front of your neck, just under your Adam's apple. It is shaped like a butterfly and moves up and down when you swallow.

Your thyroid makes a hormone called thyroxine (say: thi-rocks-in). If it makes too little, the condition is called hypothyroidism (say hy-po-thy-royd-is-em). Having too little thyroxine makes a kid grow more slowly. Doctors can do a simple blood test for hypothyroidism. If it's needed, a kid can take the missing hormone as a pill.

Other Reasons Why Kids Might Not Grow Normally

Hormones play a major role in growth, but kids might not grow normally for other reasons, including:

• Chronic diseases. These include heart and kidney problems, cystic fibrosis, juvenile rheumatoid arthritis, and sickle cell anemia, which may slow growth in some cases.
• Complications during pregnancy. One of the reasons a pregnant woman is warned not to smoke or drink is because it may slow down her baby's growth. A baby may be too small when it's born and some remain small for life. This condition is called intrauterine (say: in-trah-yu-ter-in) growth retardation, or IUGR. Some infections during pregnancy, other pregnancy problems, and certain genetic diseases can also cause this problem.
• Failure to thrive. Some babies don't grow and gain weight normally after they're born. This is called failure to thrive (FTT). FTT may happen when a child simply doesn't get enough to eat. Some babies may have an illness that needs to be treated, but most will grow normally after they start eating enough food.
• Genetic conditions. Some genetic conditions can also cause children to not grow as they should. Some girls who are short may have Turner syndrome. This means they have one X chromosome instead of two, or that one of their X chromosomes is abnormal. Another genetic condition, Marfan syndrome, makes a person tall, with very long legs and arms. The person may also have heart and eye problems.

Many of these growth disorders can be successfully treated today. With help, kids who might once have ended up very short can grow up more like other children. And that's a happy ending to any fairy tale!

Reviewed by: Steven Dowshen, MD
Date reviewed: June 2011