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.

Many causes of short stature have been discovered over the past few years, but there are still factors that are not yet understood.  ISS falls into this latter category.  Although the reasons for most cases of ISS are not yet totally understood, it is known that the administration of growth-promoting treatments may help some affected children.

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 any chronic medical condition or hormonal abnormality.

The work-up for a diagnosis of ISS, although a simple diagnosis, may require a series of blood and/or radiology tests to be done 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 Federal Drug Administration 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, M.D.
Professor of Pediatrics
Keck School of Medicine of USC
Chief, Center for Endocrinology, Diabetes & Metabolism
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