Macrothrombocytopenia (Cairn/Norfolk Terrier Type)

$75.00 (RRP)



This is a condition characterized by oversized platelets and a seemingly low platelet count. The name is derived from words macro (large) and thrombocyte (platelets).  The causative mutation was originally identified in the Cavalier King Charles Spaniel, and later a similar mutation was also discovered in affected Norfolk Terriers and Cairn Terriers.

Platelets, or thrombocytes, have a key role in bleeding prevention through clumping of blood vessel injuries. Although this dondition caseues abnormalities in size of platelets. Platelets in affected dogs function normally, and affected dogs do not show any health problems or prolonged bleeding time. Some studies suggested other health issues such as heart disease may be related to large plateles, but more researfch is needed to confirm this theory.


Haemolymphatic - Associated with the blood and lymph


Tubulin beta 1 class VI (TUBB1) on Chromosome 24

Variant Detected:

Base Substitution c.5G>A p.Arg2His


It is a trait and so is tested based on preference, not usually for health concerns.

Mode of Inheritance:

Autosomal Recessive

Research Citation(s):

Gelain, ME. A novel point mutation in the ?1?tubulin gene in asymptomatic macrothrombocytopenic Norfolk and Cairn Terriers (2014) Vet Clin Path 43(3);317-321.

Associated Breed(s):

Cairn Terrier, Mixed Breed, Norfolk Terrier , Norwich Terrier,