Vein of Galen malformation (VGM) is an uncommon blood vessel disorder usually identified in childhood. It is estimated that around ten children with this condition are born in the UK each year.

The malformation is the result of persistence of a vein (blood vessel) which is normally present early on during pregnancy (during embryonic development) but which usually disappears before the baby's birth. If this blood vessel persists, it results in an abnormal communication between the arteries and veins of the brain. Arteries are blood vessels which take blood to the brain and veins take blood away; they are usually separated by a network of finer vessels called capillaries. In VGM, there is direct communication between arteries and veins, bypassing capillaries, a process called arteriovenous shunting. There can be single or multiple communications.

Arteriovenous shunting has several potential effects. As blood usually flows faster in arteries than in veins, arteriovenous shunting means that the rate of flow in the veins is increased. This increased flow puts a strain on other organs of the body, especially the heart in young babies. Arteriovenous shunting also means that it is difficult for the veins to do their job of soaking up and circulating water from the brain. This may mean that the brain is deprived of nutrients and energy. Finally, there is a risk of bleeding from the abnormal vessels, although this is relatively low.

The manifestations of Vein of Galen malformation will vary between individuals; however, some patterns are recognised:

• Antenatal diagnosis: sometimes VGM is identified on an ultrasound done before the baby is born. The mother may be transferred closer to a centre with experience of VGM prior to delivery so that the baby can be assessed soon after birth;
• Neonatal presentation: Some babies present in the early days of life with heart failure secondary to the increased flow though the VGM;
• Infants may present with difficulties in achieving developmental milestones or with a large head size (due to increased water in the brain);
• Older children may present with seizures, developmental difficulties or a large head size.

Treatment of children with VGM consists of treatment of the abnormal blood vessels and treatment of secondary complications, such as cardiac failure. Treatment of the vascular problem is undertaken in a procedure known as embolisation. This is a technique used to block the abnormal communication(s) between arteries and veins, commonly using glue. More than one session of treatment may be required.

Inheritance patterns
Not applicable.

Prenatal diagnosis
It is possible that in some cases of VGM can be identified on Ultrascan.

Medical text written June 2005 by Dr V Ganesan, Senior Lecturer and Hon. Consultant Paediatric Neurologist, Institute of Child Health, London, UK.

Further Online Resources
Medical texts in The Contact a Family Directory are designed to give a short, clear description of specific conditions and rare disorders. More extensive information on this condition can be found on a range of reliable, validated web sites and links to them are included in the CD-ROM version of this Directory. Further information on these resources can be found in our Medical Information on the Internet article.

VEIN OF GALEN SUPPORT GROUP

Vein of Galen Support Group
28 Southgate Drive
Wincanton BA9 9ET
Tel: 01963 34393
e-mail: support@veinofgalen.co.uk
Web: http://www.veinofgalen.co.uk

This is a parent support group, established in the UK in 1999 by parents of affected children. It offers support by telephone, letter and e-mail, information on the condition and linking families where possible. There is a forum for families available on the group's website. The group aims to increase awareness of Vein of Galen malformation within the medical profession and provide information for families who have children with this rare condition. Via the website, the group is in contact with parents worldwide.

Group details last confirmed November 2007.