Learn the basics of severe primary IGF-1 deficiency.

Signs and symptoms.

Although children with SPIGFD are typically normal size at birth, they grow more slowly during infancy and childhood. They have normal body proportions, but because of their small size, they appear younger than their calendar age.

Understanding IGFD types

Children with idiopathic short stature (“idiopathic” means the cause has not been identified) are often treated with growth hormone replacement therapy, but they may not respond—because their growth hormone levels aren't actually low.

When a child is diagnosed with idiopathic short stature and does not respond to growth hormone therapy, a reevaluation might be needed. This involves the doctor checking to see if the patient is taking their medication, if the growth hormone dose needs to be adjusted, or if another diagnosis—such as severe primary IGF-1 deficiency (IGFD)—should be considered.

Understanding severe primary IGFD - a disorder defined by low IGF-1 levels

Insulin-like growth factor deficiency, or IGFD, is a big word that describes lower levels in the body of IGF-1, a naturally occurring hormone that plays a central role in human growth. Sometimes you hear IGFD classified as secondary IGFD, primary IGFD or severe primary IGFD:

  • Secondary IGFD happens in children whose IGF-1 levels are low; this may be due to their bodies' inability to produce enough growth hormone, poor nutrition, thyroid problems or other factors
  • Primary IGFD may happen when IGF-1 levels are low, even though growth hormone levels are normal or even high
  • Severe primary IGFD is a type of primary IGFD in which IGF-1 levels are exceptionally low, despite sufficient or high growth hormone levels

Taking many factors into account

Before making a diagnosis of severe primary IGFD, the doctor will likely do all of the following: perform a thorough evaluation, check height and weight, do a bone scan, and test the levels of growth hormone and IGF-1. Here are the key factors that point to the diagnosis:

  • The child is shorter than almost all other children of the same age and sex, and
  • Levels of IGF-1 in the body are much lower than normal, and
  • Levels of growth hormone in the body are normal or even high


Important Safety Information & Indication

Who should not use INCRELEX?

Your child should not take INCRELEX if your child: has finished growing, has cancer, has other causes of growth failure, or is allergic to mecasermin or any of the inactive ingredients in INCRELEX. Your child should never receive INCRELEX through a vein.

What should I tell my child’s doctor before my child starts INCRELEX?

Tell your child's doctor about all of your child's health conditions, including if your child has diabetes, kidney problems, liver problems, allergies, curved spine (scoliosis), or is pregnant or breast-feeding.

Tell your child’s doctor about all the medicines (prescription and nonprescription), vitamins, and herbal supplements your child takes. Especially tell your child’s doctor about insulin or other anti-diabetes medicines; a dose adjustment may be needed.

What are possible side effects of INCRELEX?
INCRELEX may cause the following side effects, which can be serious:

  • Low blood sugar (hypoglycemia). Only give your child INCRELEX right before or right after (20 minutes on either side of) a snack or meal to reduce the chances of hypoglycemia. Do not give your child INCRELEX if your child is sick or cannot eat. Signs of low blood sugar are: dizziness; tiredness; restlessness, hunger, irritability, trouble concentrating, sweating, nausea, and fast or irregular heartbeat. Severe hypoglycemia may cause unconsciousness, seizures, or death. People taking INCRELEX should avoid participating in high risk activities (such as driving) within 2 to 3 hours after an INCRELEX injection.
  • Enlarged tonsils. Signs include: snoring, difficulty breathing or swallowing, sleep apnea (a condition where breathing stops briefly during sleep), or fluid in the middle ear.
  • Increased pressure in the brain (intracranial hypertension). INCRELEX, like growth hormone, can sometimes cause a temporary increase in pressure within the brain. Symptoms include persistent headache and nausea with vomiting.
  • A bone problem called slipped capital femoral epiphysis. This happens when the top of the upper leg bone (femur) slips apart from the rest of the bone. Seek immediate medical attention if your child develops a limp or has hip or knee pain.
  • Worsened scoliosis (caused by rapid growth).
  • Allergic reactions. Your child may have a mild or serious allergic reaction with INCRELEX. Call your child's doctor right away if your child gets a rash or hives. If hives do occur, they generally appear minutes to hours after the injection and may sometimes occur at numerous places on the skin. Get medical help immediately if your child has trouble breathing or goes into shock, with symptoms like dizziness, pale, clammy skin, and/or passing out.

INCRELEX can cause reactions at the injection site including: loss of fat, increase of fat, pain, redness, or bruising, which can be avoided by changing the injection site at each injection.

These are not all the side effects of INCRELEX. Call your child’s doctor if your child has side effects that are bothersome or that do not go away. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.


INCRELEX is a prescription medicine used to treat children who are very short for their age because their bodies do not make enough insulin-like growth factor-1 (IGF-1). This condition is called severe primary IGF-1 deficiency. INCRELEX should not be used instead of growth hormone. INCRELEX has not been studied in children under 2 years of age.

Click here to view Increlex® Full Prescribing Information and Patient Information.


Who should not use INCRELEX®?

Your child should not take INCRELEX if your child: has finished growing (the growth plates at the end of the bones are closed); has cancer; has other causes of growth failure; OR is allergic to mecasermin or any of the inactive ingredients in INCRELEX. INCRELEX has not been studied in children under 2 years of age and should never be used in newborns. Your child should never receive INCRELEX through a vein.

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