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| + | [[Image:Grey Collie Syndrome.jpg|thumb|right|150px|Appearance of a puppy with Grey Collie syndrome - Copyright Michelle Tennis & Peggy Melton]] |
| − | Also known as: '''''Grey Collie Syndrome — Cyclic Neutropaenia
| + | *Also called '''Grey Collie Syndrome''' |
| − | | + | *Autosomal recessive |
| − | ==Introduction==
| + | *Insertion mutation in AP3B1 gene |
| − | Cyclic haematopoiesis is a disease inherited in an autosomal recessive manner. It is associated with an insertion mutation in the gene AP3B1 and it results in defective production of blood cells by bone marrow stem cells. The disease has only been described in grey collies which are homozygous for the genetic mutation; heterozygous animals do not show clinical signs.
| + | *Diluted grey coat colour, stunted growth, poor wound healing |
| − | | + | *Neutropenia every 2 weeks which lasts 3-4 days due to cyclic production of cells from [[Bone Marrow - Anatomy & Physiology|bone marrow]] |
| − | From around 7 weeks of age, affected animals begin to show cyclic waves of [[Neutropenia|neutropenia]] and of other cell type reductions. The reductions in other cell types (including platelets, eosinophils and red blood cells) do not occur in synchrony with each other or the neutropenia and bouts of reduction are interspersed with periods of marked blood cell overproduction. The periods of neutropenia last for approximately 2-4 days and are associated with severe systemic infections, including pneumonia, oronasal infection, bacterial enteritis, septic arthritis and sepsis.
| + | *Animals are prone to recurrent infections, mainly from the respiratory and gastrointestinal tract |
| − | | + | **E.g. pyrexia, [[Diarrhoea|diarrhoea]], gingivitis and arthritis |
| − | During the periods when cell numbers are increased, it is thought that cytokines drive the production and deposition of amyloid proteins in various tissues, including the kidney, liver, spleen and pancreas. Almost all affected animals develop this further disease and it ultimately results in organ failure.
| + | *Puppies can be distinguished from other litter mates by the diluted grey colouring |
| − | | + | *Affected puppies show symptoms such as fever, joint pain and eye, skin and respiratory infections from 8 weeks of age |
| − | Affected animals rarely survive to sexual maturity and the disease is transmitted by heterozygous carriers.
| + | *Affected animals rarely live beyond 2-3 years with most puppies dying within a few weeks of birth |
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| − | ==Signalment==
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| − | The disease has only been described in grey collies which are homozygous for the genetic mutation.
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| − | ==Diagnosis==
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| − | ===Clinical Signs===
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| − | [[Image:Grey Collie Syndrome.jpg|thumb|Appearance of a puppy with Grey Collie syndrome<br><small>Copyright Michelle Tennis & Peggy Melton]]</small> | |
| − | Affected animals have a '''diluted grey coat colour''' and are often '''smaller than their litter mates'''. The majority of other clinical signs relate to the reductions in various types of cell, including:
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| − | * '''Pyrexia''', '''lethargy''' and '''depression''' due to infection which develops rapidly in neutropenic animals. | |
| − | * Signs of specific infections, including dyspnoea, diarrhoea, oral, nasal and ocular discharge, joint pain and generalised lymph node enlargement. | |
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| − | Most affected animals die within a few weeks of birth and rarely survive to 2-3 years.
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| − | ===Laboratory Tests===
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| − | Alterations in cell numbers can be documented by serial blood samples and subsequent haematological analysis.
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| − | ===Other Tests===
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| − | '''Bone marrow aspirates''' can be used to demonstrate alterations in the erythroid: myeloid ratio, changes that generally precede the fluctuations in blood cell levels.
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| − | '''Genetic tests''' are available to detect the mutation. These tests can be used to detect heterozygous carriers and to prevent them from breeding.
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| − | ==Treatment==
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| − | Supportive therapy is indicated to treat infectious disease, [[anaemia]] or bleeding disorders caused by reductions in blood cell numbers. For long term management of the condition, injections of recombinant G-CSF (Granulocyte-Colony Stimulating Factor) or SCF (Stem Cell Factor) may be used to stimulate the production of leucocytes from bone marrow stem cells. These products are expensive and not widely available but they may result in prolonged survival without significant adverse effects.
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| − | ==Prognosis==
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| − | Unless treatment with recombinant cytokines can be initiated, affected animals have an extremely poor prognosis and are unlikely to survive beyond 2 years of age.
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| − | {{Learning
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| − | |literature search = [http://www.cabdirect.org/search.html?q=((title:(Cyclic))+AND+(title:(Haematopoiesis)+OR+title:(hematopoiesis)+OR+title:(haemopoiesis)+OR+title:(hemopoiesis))+AND+(od:(dogs)))+OR+title:(%22Grey+Collie+Syndrome%22)+OR+title:(%22Cyclic+Neutropaenia%22) Canine Cyclic Haematopoiesis publications]
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| − | {{review}}
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| | [[Category:Primary Innate Immunity Deficiencies]] | | [[Category:Primary Innate Immunity Deficiencies]] |
| − | [[Category:Lymphoreticular and Haematopoietic Diseases - Dog]]
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| − | [[Category:Expert Review]]
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