Inherited erythrocyte pyruvate kinase deficiency in a beagle dog

A 1-year-old, female Beagle dog with minimal exercise intolerance was found to have a persistent, severe, and highly regenerative anemia, splenomegaly, and progressive osteosclerosis. Despite near-normal in vitro erythrocyte pyruvate kinase (PK) activity, the authors diagnosed PK deficiency by demonstrating a glycolytic block at the PK step, the lack of normal R-type PK isoenzyme, and the presence of M(2)-type PK in the animal's erythrocytes. The dam had half-normal erythrocyte PK activity, which supports an autosomal recessive mode of inheritance. We conclude from our studies that close similarities exist between erythrocyte PK deficiency in Beagle, Basenji, and West Highland White Terrier dogs and that this form of PK deficiency may be more widespread than previously thought.     

Utilization of an enzyme heat stability test and erythrocyte glycolytic intermediate assays to assist in the diagnosis of canine pyruvate kinase deficiency

A macrocytic hypochromic anemia, with marked reliculocytosis and large numbers of circulating nucleated erythrocytes, was recognized in a 3 1/2-year-old male Beagle-cross dog. A presumptive diagnosis of erythrocyte pyruvate kinase (PK) deficiency was made, even though PK activity from the patient was within the range of activities measured for normal dogs, because the PK activity should have been several times normal in light of the large number of reticulocytes present. The PK activity in a hemolysate from the patient was heat-labile compared to activities in hemolysates from normal dogs, a finding consistent with results from a previous study of PK-deficient Basenji dogs. Seven phosphorylated glycolytic intermediates and 2,3-diphosphoglycerate were measured in protein-free extracts of erythrocytes from the patient. All were present in concentrations above that present in normal canine erythrocytes, further supporting the diagnosis of PK deficiency.     

Erythrocyte pyruvate kinase deficiency in three West Highland white terriers in Ireland and the UK

Erythrocyte pyruvate kinase (PK) deficiency is described for the first time in three apparently unrelated West Highland white terriers (WHWT) from Ireland and the UK. All three dogs were diagnosed with markedly regenerative but persistent anaemia and had been treated for presumed immune-mediated haemolytic anaemia (IMHA) before hereditary erythrocyte PK-deficiency was confirmed by breed-specific DNA mutation analysis. This hereditary erythroenzymopathy causes haemolytic anaemia and affects several canine breeds with varying degrees of severity. Although eventually causing osteosclerosis, haemosiderosis and death, PK-deficient dogs can adapt to their anaemia for many years.PK-deficiency should be considered in anaemic WHWTs worldwide particularly in dogs with haemolytic anaemia where evidence for an immune-mediated, infectious or toxic underlying cause is lacking.     

Pathogenesis, laboratory diagnosis, and clinical implications of erythrocyte enzyme deficiencies in dogs, cats, and horses

Deficiencies of enzymes involved in erythrocyte metabolism can have significant effects on erythrocyte function and survival. Animals with pyruvate kinase (PK) or phosphofructokinase (PFK) deficiencies have shortened erythrocyte life spans and regenerative anemia. PK-deficient dogs (but not PK-deficient cats) develop progressive myelofibrosis and osteosclerosis of bone marrow and hemochromatosis and cirrhosis of the liver. PFK-deficient dogs have sporadic episodes of hyperventilation-induced intravascular hemolysis and hemoglobinuria. Cytochrome b5 reductase (Cb5R) deficiency in dogs and cats results in persistent methemoglobinemia and cyanotic mucous membranes. Severe deficiency of glucose-6-phosphate dehydrogenase, the rate-controlling enzyme in the pentose phosphate pathway, resulted in anemia with eccentrocytosis in an American saddlebred colt. Horses with erythrocyte flavin adenine dinucleotide (FAD) deficiency have both eccentrocytosis (attributable to severe deficiency in glutathione reductase activity) and methemoglobinemia (attributable to Cb5R deficiency); the dual enzyme deficiency occurs because FAD is a required cofactor for both enzymes. Erythrocyte enzyme deficiencies do not usually shorten life expectancy, except for PK-deficient dogs and potentially PFK-deficient dogs during a hemolytic crisis. Although enzyme deficiencies are rare causes of anemia and methemoglobinemia, the ability to diagnose deficient animals allows for the possibility of eliminating these undesirable traits in future breeding. DNA-based assays are available for PK and PFK deficiencies; whereas, biochemical tests of enzyme activity are required for other deficiencies. Continued research is needed to document additional enzyme deficiencies that likely occur and to develop additional DNA-based assays to detect heterozygous animals.     

The effects of aging on hematology and serum chemistry values in the beagle dog

To distinguish age-related changes in hematology and clinical chemistry values from those resulting from disease, hematology, and clinical chemistry values of healthy, age-matched Beagle dogs 3 to 14 years of age were analyzed. Serum potassium, total protein and globulin concentration, and lactic dehydrogenase activity increased with age, while urea nitrogen, creatinine and albumin concentration, and gamma-glutamyl transferase activity decreased. The 12-year-old group had some distinct differences from the other age groups: glucose concentration was lower, alanine aminotransferase and aspartate aminotransferase activity and triglyceride concentration were higher. No significant age-related differences were found in the hematology parameters analyzed. This report extends the documented, age-related changes in normal Beagle dogs to 14 years of age. The age-related changes in organ-specific serum chemistries such as urea nitrogen and creatinine (kidney), and alanine aminotransferase (liver) noted here suggest that 12 years may be a pivotal age for determining longevity in the Beagle dog.     

A retrospective study of 60 cases of eccentrocytosis in the dog

BACKGROUND: Eccentrocytes are RBCs that appear in a peripheral blood smear to have their hemoglobin shifted to one side of the cell. This abnormality, which is confined to the RBC membrane and cytoskeleton, is induced by oxidative damage. Eccentrocytes have been reported rarely in dogs and are associated with onion and garlic ingestion and the administration of oxidant drugs. OBJECTIVE: The purpose of this study was to describe the occurrence and severity of eccentrocytosis in dogs and the diseases or disorders associated with eccentrocytes. METHODS: Detailed history, and results of physical examination, CBC, biochemical and coagulation profiles, and urinalysis from all canine patients admitted during a 2.5-year period were evaluated. Eccentrocytes, when observed, were graded 1+ (few) to 4+ (many). The severity of eccentrocytosis was compared with that of anemia and reticulocytosis. RESULTS: Eccentrocytes were found in blood smears from 60 of 4251 dogs (1.4%) and were associated with mild to moderate anemia in 40 (66.6%) of the cases. Eccentrocytosis was found in 16 (26.6%) dogs with drug administration, 11 (18.3%) with presumptive onion and garlic ingestion, 8 (13.3%) with vitamin K antagonist intoxication, 7 (11.6%) with ketoacidotic diabetes, 5 (8.3%) with T-cell lymphoma, 4 (6.6%) with severe infections, 1 (1.6%) with compensated diabetes mellitus, and 8 (13.3%) with other conditions. Certain dog breeds, such as Whippet, Boxer, and English Setter, and young dogs seemed to be overrepresented. CONCLUSIONS: We describe, for the first time, associations between eccentrocytes and diabetes mellitus, T-cell lymphoma and vitamin K antagonist intoxication in dogs. The significance of eccentrocytes should not be underestimated, because they can be a signal of an oxidative process.     

Pyruvate kinase deficiency anaemia in a Basenji dog

SUMMARY Pyruvate kinase deficiency anaemia was suspected in an 18-month-old male Basenji dog after other known causes of canine haemolytic anaemia had been excluded. Anaemia of moderate severity (packed cell volumes 0.20 to 0.26 1/1) and reticulocytosis (uncorrected reticulocyte counts 8 to 43%) persisted during 5 months' observation, and biopsies showed development of bone marrow fibrosis and sclerosis. The diagnosis of pyruvate kinase deficiency anaemia was presumptive because erythrocyte pyruvate kinase concentrations in the affected dog were inconclusive and related animals were not available for enzyme assay. However, the gene for pyruvate kinase deficiency is known to occur among Basenji dogs in Australia.     

Erythrocytic pyruvate kinase deficiency and AB blood types in Australian Abyssinian and Somali cats

Objective   To determine the frequency of the mutant pyruvate kinase (PK) allele, haematological parameters and AB blood types of Abyssinian and Somali cats in Australia.
Design   Complete blood cell and reticulocyte counts, DNA PK mutation testing and blood typing were performed in all cats.
Results   A total of 60 cats (36 Abyssinians, 24 Somalis) were included (37 females, 23 males). For the mutant PK allele, three female Somalis were homozygous (affected, 5%), 17 cats were heterozygous (carrier, 28%) and 40 cats tested negative (normal, 67%). Pedigree analysis revealed common ancestry of affected and many carrier cats. Of affected cats, two had regenerative anaemias and all had reticulocytosis (range 64–390 × 10⁹/L; P < 0.001 compared with normal or carrier cats). The only consistent historical sign was lethargy. One affected cat was euthanased 18 months after testing, because of anaemia, neutropenia, anorexia and weight loss. The mutant allele frequency was 0.19 overall (0.29 in Somalis, 0.13 in Abyssinians). All cats had blood type A. The commercial blood typing card method incorrectly identified 12 cats as having type AB blood.
Conclusions    The frequency of the mutant PK allele is high in Australia. Screening for PK deficiency is indicated before mating and in individual cats of these breeds, even in the absence of anaemia and especially when there is reticulocytosis. Although all cats in the present study had blood type A, blood type B is common in these breeds worldwide. Retyping of any AB typed cats by a laboratory technique is recommended.     

Hypothalamic-pituitary axis deficiency following traumatic brain injury in a dog

Objective – To describe endocrine dysfunction associated with traumatic brain injury in a dog.
Summary – A 12-week-old dog presented with traumatic brain injury and did not respond to traditional supportive care. Continued hypothermia, electrolyte derangements, hypotension, and hyposthenuria prompted screening for and detection of several hypothalamic-pituitary disorders including: hypoadrenocorticism, central diabetes insipidus, hypothyroidism, and growth hormone deficiency. Electrolyte abnormalities, urine osmolarity, and blood pressure improved with treatment for the associated disorders.
New or Unique Information Provided – This is the first report of generalized hypothalamic-pituitary dysfunction or panhypopituitarism following traumatic brain injury in a dog.     

Pyruvate kinase deficiency anemia with terminal myelofibrosis and osteosclerosis in a beagle.

A 15-month-old male Beagle with chronic hemolytic anemia was found to have erythrocytic pyruvate kinase deficiency and, terminally, myelofibrosis and osteosclerosis. The dog's erythron was studied by procedures that enabled close comparison with congenital hemolytic anemia (pyruvate kinase deficiency) of Basenji dogs. The affected dog's sire, dam, and one littermate--each clinically and hematologically normal--were found to have 50% reduction in erythrocytic pyruvate kinase (PK) activity.     

Hereditary factor VII deficiency in the Alaskan Klee Kai dog

BACKGROUND: Hereditary factor VII (FVII) deficiency is characterized as a mild bleeding disorder in Beagles, caused by a missense mutation in exon 5 of the FVII gene. An Alaskan Klee Kai dog with severe bleeding after trauma was diagnosed with FVII deficiency based on coagulation testing. Molecular analyses were undertaken to identify the genetic basis of the defect in this breed. HYPOTHESIS: FVII deficiency in Alaskan Klee Kai dogs is caused by a mutation in the FVII gene. ANIMALS: Eighteen client-owned Alaskan Klee Kai. METHODS: Coagulation screening tests and factor assays were performed to characterize the coagulopathy. All coding regions of the propositus' FVII gene were sequenced. Amplification of exon 5, sequencing, and Mnl I restriction digest experiments were performed to screen for a point mutation in the remaining 17 dogs. RESULTS: FVII deficiency was diagnosed in 6 dogs with a median FVII activity (FVII: C) of 5% (reference range, 50 150%). All FVII-deficient Alaskan Klee Kai were homozygous for the same mutation as FVII-deficient Beagles (ie, a G to A transition), resulting in substitution of glycine 96 by glutamic acid. An overlap in the FVII: C values obtained from heterozygote and wild-type dogs precluded accurate detection of carriers without genetic screening. CONCLUSIONS AND CLINICAL IMPORTANCE: FVII deficiency may be associated with a bleeding tendency and should be considered in Alaskan Klee Kai dogs with prolonged prothrombin times. Plasma FVII: C accurately identifies affected dogs, but deoxyribonucleic acid testing is required for identification of carriers.     

Theileria annae in a young Swedish dog

A severe regenerative anemia was detected in a 12-week-old mixed breed puppy in Sweden.A small protozoan parasite was observed in erythrocytes on a blood smear. It was initially suspected to be Babesia gibsoni based on its size and because B. gibsoni was previously recorded in Sweden.Surprisingly, specific polymerase chain reaction analysis identified the protozoan as Theileria annae. T. annae is endemic in Northwest Spain, is very uncommonly reported elsewhere and has never been recorded in Scandinavia. T. annae has been identified in dogs used for dog fighting, and it is thought to be transmitted by dog bites. This puppy was a mixed pit bull terrier. Pit bull terriers are sometimes used for dog fighting. T. annae has been reported to be transmitted vertically, and in light of the puppy’s age, this transmission was suspected in the present case.     

May-Hegglin anomaly in a dog

An 8-year-old female spayed Pug dog was presented for evaluation of cutaneous lesions occurring secondary to immunosuppressive treatment of presumed immune-mediated thrombocytopenia. Abnormal hematologic findings included persistent thrombocytopenia, macrothrombocytes, and variably shaped, often fusiform, blue cytoplasmic inclusions in neutrophils. May-Hegglin anomaly (MHA) was suspected based on the morphologic appearance of platelets and neutrophils. Examination of cells by transmission electron microscopy revealed normal platelet ultrastructure; neutrophil inclusions had features similar to those reported for inclusions in human MHA. Neutrophil function was within normal limits based on flow cytometric analysis. Thrombelastography indicated a prolonged clotting time (r), and PlateletMapping showed a lack of response to 2 μM ADP compared with a moderate response in the control dog. Immunocytochemical staining of blood smears using 2 commercially available antibodies against MYH9 protein (nonmuscle myosin heavy chain II) yielded negative results. However, genomic DNA sequencing analysis of the dog's MYH9 gene identified a single point mutation, resulting in substitution of lysine for glutamine at the 1841 amino acid position; this mutation is identical to one identified in people with MHA. To our knowledge, this is the first report of an MYH9 mutation in the dog. MHA-associated macrothrombocytopenia may be mistaken for immune-mediated thrombocytopenia.     

Creatine kinase in the dog: A review

In the dog, creatine kinase (CK) is mostly present in the skeletal muscles, myocardium, brain and intestine. The MM isoenzyme predominates in muscles and myocardium. In plasma, reference values depend on the technique used and CK-MB accounts for about 30–45% of total CK activity. Sex has no influence on plasma CK activity, which is higher in young dogs than in adults. Plasma CK is elevated after physical exercise. After its release from the cells, CK reaches the plasma mostly via the lymphatic route and then remains in the plasma compartment. It is rapidly cleared with a half-life of about 2 hours. Muscle diseases are the main source of plasma CK elevations: inherited myopathies, malignant hyperthermia, hypothyroidism, vitamin E-selenium deficiency, prolonged decubitus, intramuscular injections, surgery, etc. Plasma CK is also increased in experimental myocardial infarction, for which the dog is an interesting model, allowing quantification of the damage by measuring the total CK activity released.Abbreviations ADP adenosine diphosphate - ATP adenosine triphosphate - CK creatine kinase - DGKC Deutsche Gesellschaft für klinische Chemie - IM intramuscular - IV intravenous - K _m Michaelis constant - poly(A) polyadenylate - RNA ribonucleic acid - mRNA messenger RNA     

Suspected spontaneous hyperadrenocorticism in a young experimental beagle dog

A 6-month-old female beagle dog, assigned to the low-dose group in a toxicity study, was evaluated for compound toxicity, and spontaneous hyperadrenocorticism was suspected. The animal had an externally apparent distended abdomen on clinical examination upon arrival. Pre-dose clinical pathology showed slightly higher erythroid parameters and stress leukogram on hematology; plasma biochemistry showed higher total protein, gamma-glutamyl transferase, total cholesterol, and triglyceride levels than the reference data. On necropsy, a prominent increase in adipose tissues of the subcutis and abdomen and increased weight of the adrenal gland and liver were observed. Histopathology revealed diffuse hyperplasia of adrenocortical cells in the zona fasciculata and reticularis, cortical atrophy of the thymus, and abundant glycogen accumulation in the hepatocytes. These findings were incidental and not test-substance-related. Electron microscopy of the adrenocortical cells in the zona fasciculata revealed decreased typical translucent lipid droplets, increased electron-dense lipid droplets, and abundant smooth endoplasmic reticulum and lysosomes. Additionally, increased numbers of various sizes and forms of mitochondria with tubular, vesicular, or lamellar cristae compared to that of normal animals were observed. These ultrastructural characteristics of the adrenocortical cells suggested hyperfunction. The pre-dose plasma cortisol levels were slightly higher than those of other females assigned to the toxicity study, while plasma adrenocorticotropic hormone levels were within the normal range. These findings indicate that hyperadrenocorticism is a possible cause of the systemic changes in this case.     

Intracardiac echocardiography: use during transcatheter device closure of a patent ductus arteriosus in a dog

Intracardiac echocardiography (ICE) is used in humans for percutaneous interventional procedures, such as transcatheter device closures. Intracardiac echocardiography provides high-resolution imaging of cardiac structures with two-dimensional, M-mode, Doppler, and also three-dimensional modalities. The present report describes application of ICE during transcatheter occlusion of patent ductus arteriosus using a canine ductal occluder in a dog for which transesophageal echocardiography could not provide an optimal acoustic window.