Congenital dyserythropoiesis and polymyopathy without cardiac disease in male Labrador retriever littermates

Abstract

Background Two Labrador retriever littermates were identified based on incidentally noted marked microcytosis and inappropriate metarubricytosis. Muscle atrophy was noted and associated with distinctive pathological findings in biopsy samples from 1 dog studied. The disorder represents a rare clinical entity of suspected congenital dyserythropoiesis and polymyopathy. Clinicopathologic changes were similar to a previously reported syndrome of congenital dyserythropoiesis, congenital polymyopathy, and cardiac disease in 3 related English Springer Spaniel (ESS) dogs, but the dogs reported here did not have apparent cardiac disease. Interventions Bone marrow aspiration, electromyography, muscle biopsies, and an echocardiogram were performed on dog 1. Results supported dyserythropoiesis and congenital polymyopathy similar to reports in ESS dogs, but did not identify obvious cardiac disease. Conclusion The clinicopathologic changes of dyserythropoiesis and polymyopathy provide an easily recognizable phenotype for what appears to be a low morbidity syndrome. Early recognition may decrease unnecessary testing or euthanasia.

An EHPB1L1 Nonsense Mutation Associated with Congenital Dyserythropoietic Anemia and Polymyopathy in Labrador Retriever Littermates

“…Both X-linked myotubular myopathy (XLMTM) [ 7 , 8 ] and centronuclear myopathy (CNM) [ 9 ] have been described in Labrador Retrievers and mutations identified [ 8 , 9 ]. Of note, pathological and histochemical changes in muscle biopsies are very similar between XLMTM, CNM and the changes reported in the Labrador Retrievers and ESS with dyserythropoietic anemia and polymyopathy [ 1 , 2 ]. Such changes include excessive variability in myofiber size, central nuclei and central accumulations of oxidative activity.…”

“…The two affected Labrador Retriever littermates previously reported were evaluated further in this study. The clinical history and pathological changes in erythrocytes and muscles from both dogs were previously described [ 2 ]. A brief review of the pathological changes in erythrocytes and in myofibers is presented ( Figure 1 ) to facilitate an understanding for the non-pathologist.…”

“…An early onset of anemia, megaesophagus, generalized muscle atrophy and cardiomyopathy was observed in the English Springer Spaniels while an incidental detection of marked microcytosis, inappropriate metarubricytosis, pelvic limb weakness and muscle atrophy without cardiomyopathy were observed in the Labrador Retrievers. Despite the variable clinical presentations, similar changes were identified in erythrocyte morphology and muscle histopathology in both breeds [ 1 , 2 ].…”

“…Congenital dyserythropoietic anemia and congenital polymyopathies are rare, inherited disorders. A clinical syndrome of congenital dyserythropoiesis and polymyopathy was first reported in 1991 in young, related male and female English Springer Spaniel (ESS) dogs [ 1 ], and thirty years later in young male Labrador Retriever littermates [ 2 ]. The clinical presentation differed between the two breeds.…”

EHBP1L1 Frameshift Deletion in English Springer Spaniel Dogs with Dyserythropoietic Anemia and Myopathy Syndrome (DAMS) or Neonatal Losses

“…Dyserythropoiesis and polymyopathy were reported in three ESSPs in Australia more than three decades ago [ 17 ]. Recently, a similar syndrome was also described in two Labrador retrievers in the United States [ 18 ]. We found similarly affected ESSPs in a large family in Sweden, which prompted us to further characterize this dyserythropoietic anemia and myopathy syndrome (DAMS), investigate neonatal deaths, and search for a likely single causative genetic defect.…”