Glanzmann's thrombasthenia (GT) is a rare genetic bleeding disorder affecting the small cell fragments in the blood called platelets. Platelets are important because after injury they are the first blood components to form the plug which stops bleeding (the haemostatic plug). In patients with GT a particular protein (called IIb IIIa) is either missing from the platelets or does not work properly. The result is that the platelets cannot stick together adequately to form the haemostatic plug and bleeding is not stopped even from minor injuries. The number of platelets in the blood is normal and specialised tests are required to make the diagnosis.

Even as a child, easy bruising may be noted and in most cases the diagnosis has been made by the age of five years. The commonest problems are easy bruising, nose bleeds, heavy periods and gum bleeding. Prolonged bleeding has been reported after shedding of deciduous teeth and bleeding is of course prolonged after trauma and surgery.

Not all patients with GT are affected to the same degree. Some patients (Type 1) are severely affected while others (Type 2) are less severely affected. Even within these groups there is considerable variation. The Type 2 patients appear to have a small amount of IIb IIIa on their platelets.

Overall, whilst bleeding after trauma or surgery may be severe, problems from spontaneous bleeding in day to day life are often mild but affected women often need hormonal treatment to reduce or suppress their periods. The oral contraceptive pill may be sufficient.

Many patients, particularly women, become iron deficient as a result of frequent minor blood loss and regular iron supplements may be required.

Pregnancy in women affected by GT can be extremely hazardous, not only for the patient but for the child as well. Advice should be sought from a haematologist.

Drugs such as aspirin and ibuprofen (Nurofen, Cuprofen) which also inhibit platelet function should be avoided. Paracetamol is a useful alternative but there are others; contact your doctor for advice.

Attention to oral hygiene is important to reduce bleeding from gums. Nose bleeds often become less severe after childhood giving the impression that the disorder becomes milder with age.

Bone marrow transplantation is the only curative form of treatment. However this is generally considered more hazardous than the condition except in exceptional circumstances.

Inheritance patterns
Inheritance is autosomal recessive. It is equally common in males and females (unlike haemophilia (hemophilia - US)); carriers (the parents and some siblings of patients with GT) are unaffected and it is more common in children whose parents are related.

Prenatal diagnosis
The genes coding for IIb IIIa have been isolated and cloned. Many genetic mutations have already been described. This means that identification of affected pregnancies can be performed at an early stage, but that considerable planning is required and early medical consultation is necessary. Carriers can be identified by testing their platelets or by DNA testing.

Medical text (paediatric) written August 2001 by Dr R F Stevens, Consultant Haematologist/Oncologist, Royal Manchester Children's Hospital, Manchester, UK and (adult) November 2002 by Dr M Laffan. Last reviewed October 2005 by Dr M Laffan, Reader in Haemostasis and Thrombosis & Honorary Consultant in Haematology, Imperial College School of Medicine, 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.

GLANZMANN'S THROMBASTHENIA CONTACT GROUP

Marilyn Buxton
Glanzmann's Thrombasthenia Contact Group
28 Duke Road
Newton
Hyde
SK14 4JB
Tel: 0161 368 0219
e-mail: glanzmannsupport@btopenworld.com

This is a Contact Group, established in 1990. It offers contact through telephone and letter with newly diagnosed and affected families. It also has information and advice about problems associated with the condition. The Group is in touch with 35 families and individuals.

Group details last confirmed March 2007.