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Congenital Hyperinsulinism
Background
Congenital Hyperinsulinism: Persistent Hyperinsulinaemic Hypoglycaemia of Infancy; PHHI; Nesidioblastosis (old name)
Congenital Hyperinsulinism (CH) is a rare inherited disorder in which the regulation of the secretion of insulin is faulty and there is an over production of insulin from the beta cell of the pancreas. Insulin is the most important hormone that controls the blood glucose (sugar) level. Too much insulin leads to hypoglycaemia (low blood glucose levels). If the hypoglycaemia is not treated it can cause brain damage, learning disability and even death. It is thought that CH occurs in about 1 in 40,000 live births with a male to female ratio of 1.3 to 1. Neonatal onset CH shows in the first days or weeks after birth and is the most severe form. Infant onset CH shows in the first few months, or even years, of life and is milder. A rare adult onset form of CH has been documented. CH occurs in all ethnic groups.
What are the symptoms?
Features of hypoglycaemia in neonatal onset CH include:
- Hunger;
- Lethargy;
- Seizures;
- Apnoea ;
- Agitation/restlessness;
- Pallor;
- Poor feeding;
- Irritability;
- Sweating.
Features of infant onset CH may show:
- Any of the above symptoms;
- Confusion;
- Mood or behaviour changes;
- Excessive perspiration.
Features of the rare adult onset CH have been reported as:
- Confusion;
- Headaches, fainting;
- Loss of consciousness;
- Dizziness.
What are the causes?
A number of gene mutations are now known to be involved in CH. However, in about sixty per cent of patients the genetic basis of the disease is not known.
How is it diagnosed?
Fast diagnosis of CH can be made if blood and urine samples are taken while in an episode of hypoglycaemia. Following diagnosis, children should be referred to a specialist centre.
How is it treated?
Treatment of CH in the short term is by immediate correction of the hypoglycaemia by intravenous glucose to prevent further hypoglycaemia and brain damage. In the longer term other medications are used. A pancreatectomy (surgical intervention to remove a large or small part of the pancreas) has to be carried out where medication does not maintain proper regulation of the production of insulin.
Inheritance patterns and prenatal diagnosis
Inheritance patterns
Autosomal recessive in the case of three of the currently known mutations and autosomal dominant in the case of the remaining two known mutations. Genetic counselling should be sought in families known to be at risk of CH.
Prenatal diagnosis
In some forms of CH, amniocentesis at fifteen to eighteen weeks of pregnancy may be possible where there is already an affected family member. However, this is not possible in all forms of CH.
Is there support?
UK CHI Support Group
17 Bridge End Lane
Great Notley
Braintree
CM77 7GN
Tel: 01376 528569
e-mail: juliakill@tiscali.co.uk
Web: http://www.hi-fund.org
The group works under the Children's Hyperinsulinism Fund which is a special trustee fund of the GOSH (Great Ormond Street Hospital) children's charity and was, established in 2003 as no research was being carried out in the UK into the condition. The group offers a listening ear to families, an occasional newsletter and has information about the condition, details on request. It is advised by a consultant at the Institute of Child Health/Great Ormond Street Hospital and has over 60 families in contact.
Group details last updated July 2009.