A child’s growth is one of the best indications of overall health.  Health care providers track children’s growth to see that they are developing with a normal growth pattern. Height follows a normal bell distribution curve, and children shorter that the 2.3%ile (<-2 standard deviations, SD) can be described as having short stature.

 

There are many reasons that can lead to a child having short stature. Non-hormonal causes include malabsorption, malnutrition, liver disease, kidney disease, chronic illness, or familial short stature. Genetic syndromes can also present with short stature. Hormonal causes include low thyroid hormone (hypothyroidism), constitutional growth and pubertal delay (being a “late bloomer”), or deficiencies in the growth hormone axis (growth hormone deficiency: GHD or insulin-like growth factor-1 deficiency: IGFD).

 

Growth hormone is secreted from the pituitary gland and goes to the liver. In the liver, GH stimulates the production of IGF-1. In turn, IGF-1 goes to the growth plates in the bones for growth. Among growth hormone axis deficiencies, GHD is more common than IGFD. GHD is treated with growth hormone replacement therapy. IGFD is treated with IGF-1 replacement therapy.

 

Diagnosis

The diagnosis of IGFD is based on normal (or even high) GH levels in the presence of short stature and a low IGF-1 level. Primary IGFD is defined as short stature with a height <2.3%ile (<-2 SD) and a low IGF-1 level (<-2 SD). Severe primary IGFD is defined as a height <-3SD with an IGF-1 level <-3SD.

 

Treatment

 

IGFD can be treated with an FDA-approved therapy: IGF-1 replacement. Like GH, it is given as a subcutaneous injection. Unlike GH, it is given twice daily and with meals to prevent mild associated hypoglycemia or low blood glucose levels.

 

For more information or to network with other families of children with IGFD, contact MAGIC.

 

Contributing Medical Specialist

Aristides Maniatis, MD, FAAP
Rocky Mountain Peditaric Endocrinology
Centennial, Colorado
Assistant Clinical Professor
University of Colorado Health Sciences Center

 

Michelle’s Story

 

Michelle was born December 18, 2000.  She was a healthy 7lbs 8oz and 19 inches long, the perfect 50th percentile.  Immediately though her percentiles started to drop and have never stopped.  Her first year was filled with worry about why she was not growing.

 

We affectionately referred to Michelle as out little magic trick because everywhere we went she would amaze people.  Michelle was a very early talker and quite articulate.  She looked like she was 6 months old and was talking like she was 3.  People would get such a kick out of her. 

 

At 14 months there was no denying there was a real problem.  Finding the answer though took us 4 years, countless tests and 2 different endocrinologists!

 

Michelle was tested for Cystic Fibrosis, Turners Syndrome, Kidney disease, and numerous other disorders which all came up negative.  She had been off the growth chart for over a year and a half when her first Endocrinologist suggested we do a growth hormone stimulation test.  Everyone was shocked when it came back saying Michelle produced an elevated level of growth hormone.  While a negative result is always a good thing in this case it was devastating for us.  We wanted to help her grow so badly but we had to know what was wrong first.  Our endo basically said there was nothing more she could do.  That is when we found Dr. Brown.  He did the stimulation test again and found the same thing, elevated growth hormone levels.  He then mentioned a diagnosis that was just becoming recognized as a disorder by itself.  It was called IGF-1 deficiency.  A light went on immediately.  We had known since she was 14 months old that she had extremely low levels of IGF-1 but until now that was not considered a treatable disorder.

 

Finally a name for the problem we had been dealing with; it was very freeing!  We then had to talk about treatments.  The FDA had just approved a medicine for IGF-1 deficient children.  Like growth hormone it is given through injections.  It was very scary to think about putting our daughter on something that we have little long-term information on.  We weighed the benefits and risks for months.  Our decision came down to quality of life.  No one has died from being short but their quality of life can suffer.  We did not know what the futures holds.  However we did know  that we wanted to give our daughter every possible advantage we could.  That to us is worth the little risk any treatment might involve.

 

Michelle started on IGF therapy in November of 2006.  Unfortunately she had a bad reaction and had to be taken off after just a few weeks.   She is now on Increlex.  She gets a shot in the morning and a shot in the evening.  We have to monitor her blood sugar throughout the day.  It has made her hypoglycemic once but they altered her dose and she seems to be doing better.   We are very hopeful that this will finally help her catch up to the other kids her age. Michelle is such an amazing kid!  She has handled all the testing and treatments better than I could have ever imagined.  I am not going to say that she likes it but she is so accepting about everything.  She says this is just her special thing (she believes that God gives everyone something special).  This experience has made her a very compassionate and caring person and matured her way beyond other kids her age.  She is right about one thing God did make her very special!

 

 

 

Watch and learn about Jamie's Story