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Familial Hyperinsulinism (FHI)
Wednesday, 11 February 2004
Sunday, 28 November 2004
Persistent hyperinsulinemic hypoglycemia of infancy, nesidioblastosis


Familial hyperinsulinism (FHI) is an inherited condition in infants and young children where there are episodes of spontaneous low blood sugar (hypoglycemia). These episodes are caused by excess secretion of insulin, one of the hormones that controls blood sugar. These episodes can show up in many different ways, ranging from poor feeding to convulsions (seizures).


The frequency of familial hyperinsulinism is estimated to be close to 1 in every 50,000 births in the European population and 1 in every 2,500 births in regions of Finland and Saudi Arabia. Males are affected more often than females.

Signs and Symptoms

: Children with familial hyperinsulinism may exhibit the following: Infants (24-78 hrs after birth):

  • Poor feeding
  • Abnormal breathing pattern (apnea)
  • Diminished muscle tone
  • Convulsions (seizures) As the children become older they will have episodes of low blood sugar, which appear as:
  • Uncomfortable, jittery sensation
  • Headaches
  • Dizziness
  • Fatigue
  • Muscle pain
  • Fainting Most children will develop the symptoms of this disorder shortly after birth

Possible Causes

There are many different gene defects that have been linked to FHI and lead to uncontrolled insulin production. The two forms commonly recognized are the autosomal recessive and autosomal dominant. Children with autosomal recessive FHI inherit two defective copies of a gene and are severely affected with symptoms seen in the first few days of life. The autosomal dominant form only requires one defective gene, doesn’t show symptoms until about one year of age, and is more responsive to therapy. The disorder causes the pancreas to develop additional areas that secrete insulin, the hormone that causes blood sugar levels to decrease.


The diagnosis of FHI can be made by documenting inappropriately high blood and urine insulin levels during the times that the children have low blood sugar. Genetic testing from blood samples can also identify known gene mutations. If the diagnosis cannot be made by blood tests, your doctor may recommend a procedure known as transcutaneous percutaneous pancreatic venous sampling. This procedure involves insertion of a catheter through the liver, into a major blood vessel called the portal vein to allow direct testing of insulin levels.


The management of children with familial hyperinsulinism involves correcting hypoglycemia quickly with intravenous sugar water (glucose) to prevent irreversible brain damage. Placement of a long-term intravenous line (central venous catheter, a minor surgical procedure) may be needed in certain situations where hypoglycemia is pronounced, as this will allow glucose to be given intravenously whenever needed, or even continuously. A combination of medicines can be used to attain long-term glucose stability. Frequent snacking with carbohydrate rich foods may be needed. If medical therapy fails, surgery to remove part of the pancreas (the organ responsible for insulin production) can be pursued.


: Children with FHI who have one area of their pancreas responsible for disease are cured after surgery. However, the majority of children continue to have hypoglycemic spells their entire lives and many develop diabetes as adults.

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.

A very comprehensive article on this disease. Diabetes 123
A nice website with links to other families with similar diseases.

Google Search for Familial Hyperinsulinism (FHI)

References and Sources

Cohen, MM. (2003) Persistent Hyperinsulinemic Hypoglycemia of Infancy. Am. J. Med. Genet. 122A:351-353. Sharma, N. et al. (2000) Familial Hyperinsulinism and pancreatic beta-cell ATP-sensitive potassium channels. Kidney International 57:803-808.