What is Idiopathic Short Stature?

Idiopathic Short Stature (also known as ISS) is a big name for children who are short with no known cause.

ISS is a problem that can be present in both boys and girls.

Over the years, many causes of short stature have been identified. Genetic testing has increasingly uncovered specific reasons in some children who were thought to have ISS, but an exact cause remains unclear much of the time. Regardless, the administration of growth-promoting treatments may help some children with ISS.

ISS is defined as having a height significantly shorter than the normal population (i.e., shorter than 1.2% of the population of the same age and gender), a poor adult height prediction (generally defined as less than 5'4" for males

and less than 4'11" for females), and no detectable cause for the short stature.

Should I Take My Child to See a Growth Specialist?

You should first take your child to visit your local pediatrician who will refer your child to a growth specialist (Pediatric Endocrinologist), if necessary.

You should remember that the window of opportunity for growth ends when the growth plates fuse after puberty; therefore, the earlier you take your child for an assessment the better.

Questions to Ask Your Pediatrician

1. Is my child growing at an appropriate rate for his/her age?

2. Is my child within the normal range in his or her expected position on the growth chart?

3. Is my child on track to reach a normal expected height which is appropriate for our family?

4. Is my child at an appropriate stage of puberty for his/her age?

How is ISS Diagnosed?

ISS is normally diagnosed by a Pediatric Endocrinologist after a full investigation of the medical history, a complete physical examination, and the exclusion of various chronic medical conditions and hormonal abnormalities.

This may require that your child undergo a series of blood and/or radiology tests to rule out various medical conditions that are known to affect height.

Do Growth-Promoting Therapies Work in Children with ISS?

Growth hormone was first approved by the United States Food and Drug Administration (FDA) for use in patients with ISS in 2003 based on the successful results of clinical trials conducted in the USA and in Europe.

When started at an early enough age, growth hormone can significantly increase the final height of many children with ISS.

After completion of puberty, no further growth in height is possible. An early diagnosis is, therefore, critical to the success of the treatment.

Contributing Medical Specialist:

Mitchell E. Geffner, MD
Professor Emeritus of Pediatric
Keck School of Medicine of USC
Children’s Hospital Los Angeles
Ron Burkle Chair in the Center for Endocrinology, Diabetes & Metabolism
Co-Director, CAH Center of Excellence at CHLA
Los Angeles, California