Mutations in the CYP27B1 gene cause vitamin D dependent rickets in pugs.

Rickets is a disorder of bone development and can be the result of either dietary or genetic causes. Here, related pugs from 2 litters were included. Three pugs had clinical signs including, lameness, bone deformities, and dyspnea. One other pug was found dead. Radiographs of 2 affected pugs, 5 and 6 months old, showed generalized widening, and irregular margination of the physes of both the appendicular and the axial skeleton with generalized decrease in bone opacity and bulbous swelling of the costochondral junctions. Two pugs had low serum calcium and 1,25 (OH)2 D3 concentrations. Test results further indicated secondary hyperparathyroidism with adequate concentrations of 25-hydroxyvitamin D. Necropsy revealed tongue-like projections of cartilage extending into the metaphysis consistent with rickets, loss of metaphyseal mineralization and lung pathology. Vitamin D-dependent rickets was diagnosed. A truncating mutation in the 1α-hydroxylase gene (CYP27B1) was identified by genome sequence analysis of the pugs with VDDR type 1A. Vitamin D-dependent rickets type 1A can occur in young pugs, and if left untreated is a life-threatening condition. Early medical intervention can reverse clinical signs and should be instituted as soon as possible.

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

Hereditary myopathies are well documented in dogs, whereas hereditary dyserythropoietic anemias are rarely seen. The aim of this study was to further characterize the clinical and clinicopathological features of and to identify the causative genetic variant for a dyserythropoietic anemia and myopathy syndrome (DAMS) in English springer spaniel dogs (ESSPs). Twenty-six ESSPs, including five dogs with DAMS and two puppies that died perinatally, were studied. Progressive weakness, muscle atrophy-particularly of the temporal and pelvic muscles-trismus, dysphagia, and regurgitation due to megaesophagus were observed at all ages. Affected dogs had a non-regenerative, microcytic hypochromic anemia with metarubricytosis, target cells, and acanthocytes. Marked erythroid hyperplasia and dyserythropoiesis with non-orderly maturation of erythrocytes and inappropriate microcytic metarubricytosis were present. Muscle biopsies showed centralized nuclei, central pallor, lipocyte infiltrates, and fibrosis, which was consistent with centronuclear myopathy. The genome sequencing of two affected dogs was compared to 782 genomes of different canine breeds. A homozygous frameshift single-base deletion in EHBP1L1 was identified; this gene was not previously associated with DAMS. Pedigree analysis confirmed that the affected ESSPs were related. Variant genotyping showed appropriate complete segregation in the family, which was consistent with an autosomal recessive mode of inheritance. This study expands the known genotype-phenotype correlation of EHBP1L1 and the list of potential causative genes in dyserythropoietic anemias and myopathies in humans. EHBP1L1 deficiency was previously reported as perinatally lethal in humans and knockout mice. Our findings enable the genetic testing of ESSP dogs for early diagnosis and disease prevention through targeted breeding strategies.

Detection and phylogenetic analysis of parrot bornavirus 4 identified from a Swedish Blue-winged macaw (Primolius maracana) with unusual nonsuppurative myositis.

Background: The genus Orthobornavirus comprises RNA viruses infecting humans, mammals, birds and reptiles, where parrot bornavirus 1 to 8 causes fatal neurological and/or gastrointestinal syndromes in psittacines. There is, to the best of our knowledge, no publication describing avian bornaviruses in pet parrots in Sweden. We aimed to identify and to produce epidemiologic knowledge about the etiologic agent associated with a history of severe weight loss and death of a Primolius maracana.Methods and results: The results of histopathology, immunohistochemistry and real-time RT-PCR were compatible with avian bornavirus infection. Sequencing indicated infection by parrot bornavirus 4 (PaBV-4). The genotype reported shared high identity with PaBV-4 identified from pet psittacines and from wild birds in several countries. The N gene and X protein showed genotype clusters formation. P protein revealed to be more conserved within and between species of bornaviruses. Findings suggest horizontal transmission within and between avian orders and species.Conclusion: There seems to be a worldwide trading without biosafety measures, hence, further disease transmission could be avoided. For screening purposes, the P gene is a good candidate as a universal target in molecular diagnostics. Wild birds may be key pieces in the puzzle of bornavirus epidemiology.

Lrig2-deficient mice are protected against PDGFB-induced glioma.

BACKGROUND: The leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins constitute an integral membrane protein family that has three members: LRIG1, LRIG2, and LRIG3. LRIG1 negatively regulates growth factor signaling, but little is known regarding the functions of LRIG2 and LRIG3. In oligodendroglial brain tumors, high expression of LRIG2 correlates with poor patient survival. Lrig1 and Lrig3 knockout mice are viable, but there have been no reports on Lrig2-deficient mice to date. METHODOLOGY/PRINCIPAL FINDINGS: Lrig2-deficient mice were generated by the ablation of Lrig2 exon 12 (Lrig2E12). The Lrig2E12-/- mice showed a transiently reduced growth rate and an increased spontaneous mortality rate; 20-25% of these mice died before 130 days of age, with the majority of the deaths occurring before 50 days. Ntv-a transgenic mice with different Lrig2 genotypes were transduced by intracranial injection with platelet-derived growth factor (PDGF) B-encoding replication-competent avian retrovirus (RCAS)-producing DF-1 cells. All injected Lrig2E12+/+ mice developed Lrig2 expressing oligodendroglial brain tumors of lower grade (82%) or glioblastoma-like tumors of higher grade (18%). Lrig2E12-/- mice, in contrast, only developed lower grade tumors (77%) or had no detectable tumors (23%). Lrig2E12-/- mouse embryonic fibroblasts (MEF) showed altered induction-kinetics of immediate-early genes Fos and Egr2 in response to PDGF-BB stimulation. However, Lrig2E12-/- MEFs showed no changes in Pdgfrα or Pdgfrß levels or in levels of PDGF-BB-induced phosphorylation of Pdgfrα, Pdgfrß, Akt, or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2). Overexpression of LRIG1, but not of LRIG2, downregulated PDGFRα levels in HEK-293T cells. CONCLUSIONS: The phenotype of Lrig2E12-/- mice showed that Lrig2 was a promoter of PDGFB-induced glioma, and Lrig2 appeared to have important molecular and developmental functions that were distinct from those of Lrig1 and Lrig3.