Fifteen-year-old twins Peter and Nicholas Campbell are short. As freshmen in high school, they stand at 4 feet 2 inches each. But with a mother who is 5 feet 5 inches, a father who is 5 feet 8 inches, and no additional underlying conditions that might affect their growth, the reason for their below-average height is yet unknown.
Laurie Cohen, MD, director of the Neuroendocrinology Program at Children's Hospital Boston, has diagnosed the boys with Idiopathic Short Stature (ISS), a condition in which a child doesn't grow to a height that is within the normal range, despite physical makeup and laboratory tests being normal.
"Kids with ISS represent the shortest 2.3 percent of children," says Dr. Cohen. "But diagnosing it can be difficult, as there may be other reasons why a child is short or not growing at a normal rate." ("Ruling out ISS")
In the Campbell twins' case, questions regarding their height came up during an unrelated trip to Children's Department of Neurology to explore why Peter, who has cerebral palsy, was having seizures. Children's Neurologist David Coulter, MD, immediately recognized that the boys' height was well below the normal range for their age and gender.
"The twins were born prematurely, at just 1 pound apiece," says Gloriann, their mother. "So our pediatrician believed that had a lot to do with the fact that they weren't gaining weight or growing taller from visit to visit. He kept saying that they would catch up and develop at their own pace."
But it just didn't add up, especially given that the boys' fraternal triplet, Brett, was growing and getting relatively taller than them. So Dr. Coulter and their pediatrician referred Peter and Nicholas to Children's Endocrinology Program, where Dr. Cohen and her colleagues conducted several tests. Upon discovering that the then-14-year-olds had not yet entered puberty, the boys were put on a six-month regimen of testosterone therapy to stimulate puberty, which the doctors hoped would also foster a growth spurt.
"The Campbells' current heights were less than the first percentile," she says. "But because their original concern centered on lack of pubertal changes, we initially gave them a short course of testosterone, which doesn't actually affect final height. However, height became a concern, especially in light of their fraternal triplet's growth."
Dr. Cohen began to consider growth hormone treatment. In July 2003, the FDA (Food and Drug Administration) approved the use of growth hormone to treat ISS in kids whose height is less than 97.7 percent of others their age—and whose projected adult height is far below the average-less than 5 feet 3 inches for men and below 4 feet 11 inches for women. According to Dr. Cohen, Peter and Nicholas's current and predicted adult heights made them likely candidates for growth hormone treatment.
But the treatment doesn't turn a short child into a tall one. Typically, a child taking growth hormone for several years only grows an average of 1.5 to 3 inches, while some children may not see any improvement in final height. And while the most common side effects—muscle or bone pain, swelling of the hands and feet and occasionally a curving of the spine—closely resemble normal growing pains, the long-term effects of treating a child with ISS remain unknown.
Gloriann and her sons discussed the possibility of the twins starting growth hormone treatments, weighing the pros and cons, and considering the side effects. In the end, they determined it was the right course of action. "Being short is a different story for a teenager in high school," says Gloriann. "The boys were ridiculed for their size and told to go back to middle school by the other kids. Nicholas even came home one day saying he didn't want to go to school anymore. It's really hard for them."
The twins are scheduled to begin nightly growth hormone injections shortly and are really excited about it. "In the end, even if it only gives them an inch or two, it's worth it," says Gloriann. "We're keeping our fingers crossed that this means good things for them, and especially for their self-esteem."
According to Dr. Cohen, if a pediatrician has ruled out other underlying reasons why a child may not be growing taller at a normal rate, and can't determine the root of the problem, it's appropriate to refer to a pediatric endocrinologist. "Not every short child should be treated with growth hormone," she says. "But it's worth having a specialist take a look to determine what's going on."
Ruling out Idiopathic Short Stature
The following are other reasons a child may not be growing taller at a normal rate:
- A delay in growth and maturation, causing slower growth for a period of time.
- A condition, such as Turner syndrome, developing prior to birth or resulting from changes in chromosomes or genes.
- Chronic illnesses, like diseases of the kidneys, heart, lungs or gastrointestinal tract that affect growth.
- Certain medications used to treat illnesses, such as asthma, can slow normal growth.
- A disturbance of the growth plates in the spine or at the end of long bones, such as the legs, that affect growth.
- Problems producing growth hormone or other hormones, like cortisol or thyroid hormone.
December
2004
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