The impact of urine collection method on canine urinary microbiota detection: a cross-sectional study.

BACKGROUND: The urinary tract harbors unique microbial communities that play important roles in urogenital health and disease. Dogs naturally suffer from several of the same urological disorders as humans (e.g., urinary tract infections, neoplasia, urolithiasis) and represent a valuable translational model for studying the role of urinary microbiota in various disease states. Urine collection technique represents a critical component of urinary microbiota research study design. However, the impact of collection method on the characterization of the canine urinary microbiota remains unknown. Therefore, the objective of this study was to determine whether urine collection technique alters the microbial populations detected in canine urine samples. Urine was collected from asymptomatic dogs by both cystocentesis and midstream voiding. Microbial DNA was isolated from each sample and submitted for amplicon sequencing of the V4 region of the bacterial 16 S rRNA gene, followed by analyses to compare microbial diversity and composition between urine collection techniques. RESULTS: Samples collected via midstream voiding exhibited significantly higher sequence read counts (P = .036) and observed richness (P = .0024) than cystocentesis urine. Bray Curtis and Unweighted UniFrac measures of beta diversity showed distinct differences in microbial composition by collection method (P = .0050, R2 = 0.06 and P = .010, R2 = 0.07, respectively). Seven taxa were identified as differentially abundant between groups. Pasteurellaceae, Haemophilus, Friedmanniella, two variants of Streptococcus, and Fusobacterium were over-represented in voided urine, while a greater abundance of Burkholderia-Caballeronia-Paraburkholderia characterized cystocentesis samples. Analyses were performed at five thresholds for minimum sequence depth and using three data normalization strategies to validate results; patterns of alpha and beta diversity remained consistent regardless of minimum read count requirements or normalization method. CONCLUSION: Microbial composition differs in canine urine samples collected via cystocentesis as compared to those collected via midstream voiding. Future researchers should select a single urine collection method based on the biological question of interest when designing canine urinary microbiota studies. Additionally, the authors suggest caution when interpreting results across studies that did not utilize identical urine collection methods.

Development of a burst wave lithotripsy system for noninvasive fragmentation of ureteroliths in pet cats.

BACKGROUND: Upper urinary tract stones are increasingly prevalent in pet cats and are difficult to manage. Surgical procedures to address obstructing ureteroliths have short- and long-term complications, and medical therapies (e.g., fluid diuresis and smooth muscle relaxants) are infrequently effective. Burst wave lithotripsy is a non-invasive, ultrasound-guided, handheld focused ultrasound technology to disintegrate urinary stones, which is now undergoing human clinical trials in awake unanesthetized subjects. RESULTS: In this study, we designed and performed in vitro testing of a modified burst wave lithotripsy system to noninvasively fragment stones in cats. The design accounted for differences in anatomic scale, acoustic window, skin-to-stone depth, and stone size. Prototypes were fabricated and tested in a benchtop model using 35 natural calcium oxalate monohydrate stones from cats. In an initial experiment, burst wave lithotripsy was performed using peak ultrasound pressures of 7.3 (n = 10), 8.0 (n = 5), or 8.9 MPa (n = 10) for up to 30 min. Fourteen of 25 stones fragmented to < 1 mm within the 30 min. In a second experiment, burst wave lithotripsy was performed using a second transducer and peak ultrasound pressure of 8.0 MPa (n = 10) for up to 50 min. In the second experiment, 9 of 10 stones fragmented to < 1 mm within the 50 min. Across both experiments, an average of 73-97% of stone mass could be reduced to fragments < 1 mm. A third experiment found negligible injury with in vivo exposure of kidneys and ureters in a porcine animal model. CONCLUSIONS: These data support further evaluation of burst wave lithotripsy as a noninvasive intervention for obstructing ureteroliths in cats.

Cloning, function, and localization of human, canine, and Drosophila ZIP10 (SLC39A10), a Zn2+ transporter.

Zinc (Zn2+) is the second most abundant trace element, but is considered a micronutrient, as it is a cofactor for many enzymes and transcription factors. Whereas Zn2+ deficiency can cause cognitive immune or metabolic dysfunction and infertility, excess Zn2+ is nephrotoxic. As for other ions and solutes, Zn2+ is moved into and out of cells by specific membrane transporters: ZnT, Zip, and NRAMP/DMT proteins. ZIP10 is reported to be localized at the apical membrane of renal proximal tubules in rats, where it is believed to play a role in Zn2+ import. Renal regulation of Zn2+ is of particular interest in light of growing evidence that Zn2+ may play a role in kidney stone formation. The objective of this study was to show that ZIP10 homologs transport Zn2+, as well as ZIP10, kidney localization across species. We cloned ZIP10 from dog, human, and Drosophila ( CG10006), tested clones for Zn2+ uptake in Xenopus oocytes and localized the protein in renal structures. CG10006, rather than foi (fear-of-intimacy, CG6817) is the primary ZIP10 homolog found in Drosophila Malpighian tubules. The ZIP10 antibody recognizes recombinant dog, human, and Drosophila ZIP10 proteins. Immunohistochemistry reveals that ZIP10 in higher mammals is found not only in the proximal tubule, but also in the collecting duct system. These ZIP10 proteins show Zn2+ transport. Together, these studies reveal ZIP10 kidney localization, a role in renal Zn2+ transport, and indicates that CG10006 is a Drosophila homolog of ZIP10.

Glomerular Lipidosis in Dogs.

Glomerular lipidosis (GL) is characterized by dilated glomerular capillary loops containing lipid-laden cells (foam cells). Previously, GL was considered to be an incidental finding because affected dogs were typically not azotemic. However, the International Renal Interest Society staging system for canine chronic kidney disease has increased the awareness of other clinical parameters (eg, proteinuria and hypertension) that should be included in the assessment of renal function. As such, the aim of this study was to determine clinical abnormalities and concurrent renal lesions in dogs with GL. GL was identified in renal biopsies from 46 dogs evaluated by the International Veterinary Renal Pathology Service. GL was the sole diagnosis in 5 of 46 cases (11%), all of which were proteinuric. All 5 dogs had at least 1 additional clinicopathologic abnormality consistent with renal disease, including hypertension (4), azotemia (3), and/or hypoalbuminemia (2). The remaining 41 dogs had GL in combination with other glomerular lesions, the most common being focal segmental glomerulosclerosis (16, 35%), lesions consistent with juvenile nephropathy (8, 17%), and glomerular amyloidosis (5, 11%). Overall, dogs with severe GL were younger than were those with mild GL ( P < .001). The percentage of glomeruli affected by GL differed by concurrent diagnoses ( P = .034), with the highest percentage of affected glomeruli in dogs with GL alone or those with concurrent juvenile nephropathy. These findings suggest that GL should be a recognized histologic phenotype of glomerular injury associated with clinical renal dysfunction and/or juvenile nephropathies.

An APRT mutation is strongly associated with and likely causative for 2,8-dihydroxyadenine urolithiasis in dogs.

2,8-Dihydroxyadenine (2,8-DHA) urolithiasis in people is caused by autosomal recessive mutations in the adenine phosphoribosyltransferase gene (APRT). 2,8-DHA urolithiasis has recently been reported in two dogs, but, to the authors' knowledge, no studies have yet investigated the genetic basis for susceptibility to the development of 2,8-DHA urolithiasis in this species. Our aim was to sequence APRT in dogs affected by 2,8-DHA urolithiasis and compare the results to clinically healthy dogs of similar ancestral lineages. Our hypothesis was that we would identify an autosomal recessive mutation in APRT that is associated with the disease. The case population consisted of six dogs with a history of 2,8-DHA urolithiasis: five Native American Indian Dogs (NAIDs) and a mixed breed. The control population consisted of adult NAIDs with no history of urolithiasis. We sequenced APRT and identified a missense mutation in a highly conserved codon of APRT (c.260G>A; p.Arg87Gln). The c.260A mutation was present in a homozygous state in all six dogs with 2,8-DHA urolithiasis, and it was strongly associated with the disease. This exact missense mutation has been previously reported to cause loss of APRT enzyme function in a human cell line, and it is likely a causative mutation in dogs. Therefore, the dog offers a naturally-occurring genetic animal model for 2,8-DHA urolithiasis.

Spontaneous remission and relapse of diabetes mellitus in a male dog.

An 8-year-old male neutered Miniature Schnauzer was diagnosed with diabetes mellitus based on fasting hyperglycemia and glucosuria after a 2-week history of polydipsia and periuria, in line with the Agreeing Language in Veterinary Endocrinology consensus definition. Treatment of insulin and dietary management was initiated. The insulin dose was gradually reduced and eventually discontinued over the next year based on spot blood glucose concentrations that revealed euglycemia or hypoglycemia. After discontinuation, the dog remained free of clinical signs for 1 year until it was again presented for polyuria/polydipsia with fasting hyperglycemia and glucosuria. Insulin therapy was resumed and continued for the remainder of the dog's life. Although diabetic remission often occurs in cats and humans, the presumed etiopathogenesis of pancreatic beta cell loss makes remission rare in dogs, except for cases occurring with diestrus or pregnancy. This case demonstrates that diabetic remission is possible in dogs, even in cases without an identifiable reversible trigger.

Clustering analysis of lipoprotein profiles to identify subtypes of hypertriglyceridemia in Miniature Schnauzers.

BACKGROUND: Hypertriglyceridemia (HTG) is prevalent in Miniature Schnauzers, predisposing them to life-threatening diseases. Varied responses to management strategies suggest the possibility of multiple subtypes. HYPOTHESIS/OBJECTIVE: To identify and characterize HTG subtypes in Miniature Schnauzers through cluster analysis of lipoprotein profiles. We hypothesize that multiple phenotypes of primary HTG exist in this breed. ANIMALS: Twenty Miniature Schnauzers with normal serum triglyceride concentration (NTG), 25 with primary HTG, and 5 with secondary HTG. METHODS: Cross-sectional study using archived samples. Lipoprotein profiles, generated using continuous lipoprotein density profiling, were clustered with hierarchical cluster analysis. Clinical data (age, sex, body condition score, and dietary fat content) was compared between clusters. RESULTS: Six clusters were identified. Dogs with primary HTG were dispersed among 4 clusters. One cluster showed the highest intensities for triglyceride-rich lipoprotein (TRL) and low-density lipoprotein (LDL) fractions and also included 4 dogs with secondary HTG. Two clusters had moderately high TRL fraction intensities and low-to-intermediate LDL intensities. The fourth cluster had high LDL but variable TRL fraction intensities with equal numbers of NTG and mild HTG dogs. The final 2 clusters comprised only NTG dogs with low TRL intensities and low-to-intermediate LDL intensities. The clusters did not appear to be driven by differences in the clinical data. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study support a spectrum of lipoprotein phenotypes within Miniature Schnauzers that cannot be predicted by triglyceride concentration alone. Lipoprotein profiling might be useful to determine if subtypes have different origins, clinical consequences, and response to treatment.

Sequence Analysis of Six Candidate Genes in Miniature Schnauzers with Primary Hypertriglyceridemia.

Miniature Schnauzers are predisposed to primary hypertriglyceridemia (HTG). In this study, we performed whole genome sequencing (WGS) of eight Miniature Schnauzers with primary HTG and screened for risk variants in six HTG candidate genes: LPL, APOC2, APOA5, GPIHBP1, LMF1, and APOE. Variants were filtered to identify those present in ≥2 Miniature Schnauzers with primary HTG and uncommon (<10% allele frequency) in a WGS variant database including 613 dogs from 61 other breeds. Three variants passed filtering: an APOE TATA box deletion, an LMF1 intronic SNP, and a GPIHBP1 missense variant. The APOE and GPIHBP1 variants were genotyped in a cohort of 108 Miniature Schnauzers, including 68 with primary HTG and 40 controls. A multivariable regression model, including age and sex, did not identify an effect of APOE (estimate = 0.18, std. error = 0.14; p = 0.20) or GPIHBP1 genotypes (estimate = -0.26, std. error = 0.42; p = 0.54) on triglyceride concentration. In conclusion, we did not identify a monogenic cause for primary HTG in Miniature Schnauzers in the six genes evaluated. However, if HTG in Miniature Schnauzers is a complex disease resulting from the cumulative effects of multiple variants and environment, the identified variants cannot be ruled out as contributing factors.

Increased susceptibility to Mycobacterium avium complex infection in miniature Schnauzer dogs caused by a codon deletion in CARD9.

Mammals are generally resistant to Mycobacterium avium complex (MAC) infections. We report here on a primary immunodeficiency disorder causing increased susceptibility to MAC infections in a canine breed. Adult Miniature Schnauzers developing progressive systemic MAC infections were related to a common founder, and pedigree analysis was consistent with an autosomal recessive trait. A genome-wide association study and homozygosity mapping using 8 infected, 9 non-infected relatives, and 160 control Miniature Schnauzers detected an associated region on chromosome 9. Whole genome sequencing of 2 MAC-infected dogs identified a codon deletion in the CARD9 gene (c.493_495del; p.Lys165del). Genotyping of Miniature Schnauzers revealed the presence of this mutant CARD9 allele worldwide, and all tested MAC-infected dogs were homozygous mutants. Peripheral blood mononuclear cells from a dog homozygous for the CARD9 variant exhibited a dysfunctional CARD9 protein with impaired TNF-α production upon stimulation with the fungal polysaccharide ß-glucan that activates the CARD9-coupled C-type lectin receptor, Dectin-1. While CARD9-deficient knockout mice are susceptible to experimental challenges by fungi and mycobacteria, Miniature Schnauzer dogs with systemic MAC susceptibility represent the first spontaneous animal model of CARD9 deficiency, which will help to further elucidate host defense mechanisms against mycobacteria and fungi and assess potential therapies for animals and humans.

Dietary Features Are Associated with Differences in the Urinary Microbiome in Clinically Healthy Adult Dogs.

Nutrition plays an important role in shaping the gut microbiome composition, although the impact of diet on the urinary microbiome (i.e., urobiome) remains unknown. The aim of this pilot study was to discover how nutritional features affect the diversity and composition of the urobiome in dogs. Dietary histories were obtained for 15 clinically healthy adult dogs, including limited nutrient (protein, fat, crude fiber), commercial diet brand, and dietary diversity profiles. The urine samples were collected via cystocentesis, followed by sequencing of the bacterial 16S rRNA gene. The data were analyzed to determine associations between major nutrients and dietary sources with the urobiome's composition. The protein, fat, and crude fiber contents had no statistically significant effect on the alpha or beta diversity. However, the beta diversity values differed (PERMANOVA; p = 0.017, R2 = 0.10) between dogs fed one commercial diet brand compared to dogs consuming any other brand. The beta diversity values also differed (p = 0.019, R2 = 0.10) between dogs consuming more diverse daily diets compared to those consuming less diverse diets (≥3 or <3 unique food sources, respectively). Overall, the results of this pilot study suggest that diet might impact the urobiome and support further exploration of the relationship between diet and the urobiome's composition in dogs.

A Novel CARMIL2 Immunodeficiency Identified in a Subset of Cavalier King Charles Spaniels with Pneumocystis and Bordetella Pneumonia.

Pet dogs are a valuable natural animal model for studying relationships between primary immunodeficiencies and susceptibility to Pneumocystis and other opportunistic respiratory pathogens. Certain breeds, such as the Cavalier King Charles Spaniel, are over-represented for Pneumocystis pneumonia (PCP), suggesting the presence of a primary immunodeficiency in the breed. Here, we report the discovery of a CARMIL2 nonsense variant in three Cavalier King Charles Spaniel dogs with either PCP (n = 2) or refractory Bordetella pneumonia (n = 1). CARMIL2 encodes a protein that plays critical roles in T-cell activation and other aspects of immune function. Deleterious CARMIL2 variants have recently been reported in human patients with PCP and other recurrent pneumonias. In addition to opportunistic respiratory infection, the affected dogs also exhibited other clinical manifestations of CARMIL2 deficiencies that have been reported in humans, including early-onset gastrointestinal disease, allergic skin disease, mucocutaneous lesions, abscesses, autoimmune disorders, and gastrointestinal parasitism. This discovery highlights the potential utility of a natural canine model in identifying and studying primary immunodeficiencies in patients affected by PCP.

An ABCC9 Missense Variant Is Associated with Sudden Cardiac Death and Dilated Cardiomyopathy in Juvenile Dogs.

Sudden cardiac death in the young (SCDY) is a devastating event that often has an underlying genetic basis. Manchester Terrier dogs offer a naturally occurring model of SCDY, with sudden death of puppies as the manifestation of an inherited dilated cardiomyopathy (DCM). We performed a genome-wide association study for SCDY/DCM in Manchester Terrier dogs and identified a susceptibility locus harboring the cardiac ATP-sensitive potassium channel gene ABCC9. Sanger sequencing revealed an ABCC9 p.R1186Q variant present in a homozygous state in all SCDY/DCM-affected dogs (n = 26). None of the controls genotyped (n = 398) were homozygous for the variant, but 69 were heterozygous carriers, consistent with autosomal recessive inheritance with complete penetrance (p = 4 × 10-42 for the association of homozygosity for ABCC9 p.R1186Q with SCDY/DCM). This variant exists at low frequency in human populations (rs776973456) with clinical significance previously deemed uncertain. The results of this study further the evidence that ABCC9 is a susceptibility gene for SCDY/DCM and highlight the potential application of dog models to predict the clinical significance of human variants.

Prevalence and Predictors of Radiographically Apparent Upper Urinary Tract Urolithiasis in Eight Dog Breeds Predisposed to Calcium Oxalate Urolithiasis and Mixed Breed Dogs.

Data on upper urinary tract (UUT) uroliths in dogs are important to understanding their etiology. The aim of this retrospective case-control study was to determine the prevalence and identify predictors of radiographically apparent UUT uroliths in dog breeds at increased risk for calcium oxalate uroliths (CaOx risk breeds) and mixed breed dogs. Radiologist reports of three-view abdominal radiographs were reviewed from 251 purebred dogs of 8 CaOx risk breeds and 68 mixed breed dogs. UUT uroliths were more common in CaOx risk breeds than mixed breed dogs (23% versus 6%, respectively; OR = 4.8, 95% confidence interval [CI] 1.7−18.9, p < 0.001). UUT uroliths were more common in dogs with lower urinary tract (LUT) uroliths (predominantly calcium-containing) than those without (41% versus 5%, respectively; OR = 13.6, 95% CI 6.3−33.1, p < 0.001), and LUT uroliths predicted the presence of UUT uroliths in the multivariable regression (OR = 6.5, 95% CI 2.8−16.7, p < 0.001). Increasing age (p < 0.001) and lower body weight (p = 0.0016) were also predictors of UUT urolith presence in the multivariable regression. The high prevalence of UUT uroliths in dogs with LUT uroliths supports a shared mechanism for their formation.

Targeted sequencing of candidate gene regions for myelofibrosis in dogs.

BACKGROUND: Myelofibrosis often lacks an identifiable cause in dogs. In humans, most primary myelofibrosis cases develop secondary to driver mutations in JAK2, CALR, or MPL. OBJECTIVES: To determine the prevalence of variants in JAK2, CALR, or MPL candidate regions in dogs with myelofibrosis and in healthy dogs. ANIMALS: Twenty-six dogs with myelofibrosis that underwent bone marrow biopsy between 2010 and 2018 and 25 control dogs matched for age, sex, and breed. METHODS: Cross-sectional study. Amplicon sequencing of JAK2 exons 12 and 14, CALR exon 9, and MPL exon 10 was performed on formalin-fixed, decalcified, paraffin-embedded bone marrow (myelofibrosis) or peripheral blood (control) DNA. Somatic variants were categorized as likely-benign or possibly-pathogenic based on predicted impact on protein function. Within the myelofibrosis group, hematologic variables and survival were compared by variant status (none, likely-benign only, and ≥1 possibly-pathogenic). The effect of age on variant count was analyzed using linear regression. RESULTS: Eighteen of 26 (69%) myelofibrosis cases had somatic variants, including 9 classified as possibly-pathogenic. No somatic variants were detected in controls. Within the myelofibrosis group, hematologic variables and survival did not differ by variant status. The number of somatic variants per myelofibrosis case increased with age (estimate, 0.69; SE, 0.29; P = .03). CONCLUSIONS AND CLINICAL IMPORTANCE: Somatic variants might initiate or perpetuate myelofibrosis in dogs. Our findings suggest the occurrence of clonal hematopoiesis in dogs, with increasing incidence with age, as observed in humans.

Characterization of the urogenital microbiome in Miniature Schnauzers with and without calcium oxalate urolithiasis.

BACKGROUND: Calcium oxalate (CaOx) uroliths are common in dogs. Humans with CaOx urolithiasis exhibit alterations of the urinary and urogenital microbiomes that might mediate urolith formation. Detection of urogenital microbes associated with CaOx in dogs could inform disease pathophysiology. OBJECTIVE: To identify compositional differences in the urogenital microbiome of Miniature Schnauzers with and without CaOx uroliths. ANIMALS: Nineteen midstream, voided urine samples from Miniature Schnauzers with (n = 9) and without (n = 10) a history of CaOx urolithiasis. METHODS: Analytical cross-sectional study. Microbial DNA was extracted from previously frozen urine samples and sequenced for the bacterial 16S rRNA V3-V4 hypervariable regions. Diversity and composition of microbial populations were compared between urolith formers and controls. RESULTS: Alpha and beta diversity measures were similar between groups. Five individual bacterial taxa differed in abundance (indicator values >0.5 and P < .05): Acinetobacter, 2 Geobacillus variants, and Hydrogenophaga were overrepresented in the urine of urolith formers, and Sphingopyxis was overrepresented in controls. Two distinct subtypes of urine microbial composition were observed based on beta diversity measures, independent of urolith status, and other clinical variables. CONCLUSIONS AND CLINICAL IMPORTANCE: Although we did not detect a difference in the overall urogenital microbial composition between groups, observed differences in individual bacterial taxa might be clinically relevant. For example, Acinetobacter was overrepresented in urolith formers and is associated with CaOx urolithiasis in humans. Two unique clusters of the microbiome were identified, independent of urolith status, which may represent distinct urotypes present in Miniature Schnauzers.

Calcium oxalate urolithiasis in juvenile dogs.

BACKGROUND: The features of juvenile-onset calcium oxalate urolithiasis in dogs have not been previously reported. METHODS: Calcium oxalate urolith submissions to the Minnesota Urolith Center between 2012 and 2016 were analyzed to identify those originating from juvenile (≤2 years, n = 510) or mature (7-9 years, n = 39,093) dogs. Breed, sex, urolith salt type and urolith location were compared between groups. Breeds represented in both groups were also compared with respect to sex, urolith salt type and urolith location. RESULTS: French (odds ratios [OR] = 14.7, p < 0.001) and English (OR = 14.3, p < 0.001) Bulldogs were overrepresented in juvenile submissions. All juvenile French and English Bulldogs were male. Across all breeds, juvenile dogs were more likely to be male (89%, p < 0.001) than mature dogs (79%). Juvenile dogs were also more likely to form dihydrate stones compared to mature dogs (33% versus 14%, respectively; p < 0.001). Breed differences were discovered in sex, urolith salt type and stone location. CONCLUSIONS: French and English Bulldogs comprise a greater proportion of juvenile calcium oxalate urolith submissions than expected based on their rarity in mature submissions. Inherited risk factors, particularly X chromosome variants, should be investigated due to the strong breed and sex predispositions identified.

X-linked CD40 ligand deficiency in a 1-year-old male Shih Tzu with secondary Pneumocystis pneumonia.

An approximately 1-year-old male intact Shih Tzu dog was referred to a tertiary facility with a history of progressive tachypnea, increased respiratory effort, and weight loss over a 3-month period that failed to improve with empirical antimicrobial treatment. Upon completion of a comprehensive respiratory evaluation, the dog was diagnosed with severe Pneumocystis pneumonia and secondary pulmonary hypertension. Clinical signs resolved and disease resolution was confirmed after completion of an 8-week course of trimethoprim-sulfonamide, 4-week tapering dose of prednisone to decrease an inflammatory response secondary to acute die-off of organisms, a 2-week course of clopidogrel to prevent clot formation, and a 2-week course of a phosphodiesterase-5 inhibitor to treat pulmonary hypertension. Immunodiagnostic testing and genetic sequencing were performed to evaluate for potential immunodeficiency as an underlying cause for the development Pneumocystis pneumonia, and identified an X-linked CD40 ligand deficiency.

Retrospective analysis of the effects of Blastomyces antigen concentration in urine and radiographic findings on survival in dogs with blastomycosis.

BACKGROUND: The Blastomyces antigen concentration in urine (BACU) test is used to diagnose blastomycosis and monitor treatment in dogs. It is unknown if a higher BACU is associated with shorter survival. OBJECTIVES: To determine if the magnitude of BACU before treatment is associated with survival in dogs with blastomycosis. ANIMALS: Fifty-two dogs with blastomycosis. METHODS: Retrospective case review. BACU, radiographic lung severity (RLS) score (0-4 scale), and survival time up to 1 year after diagnosis were obtained through medical record review of dogs with Blastomyces dermatitidis. RESULTS: The overall survival was: discharge, 87%; 1 week, 85%; 2 months, 74%; and 6 months, 69%. BACU correlated with RLS score (rs = 0.33, P = .02). BACU and RLS scores were lower in survivors to 2 months than nonsurvivors (average BACU difference of 2.5 ng/mL, 95% confidence interval [CI]: 0.2-4.8 ng/mL, P = .04; median RLS difference of 2; range, 0-4, P = .02). Dogs with BACU <5 ng/mL and dogs with mild (0-1) RLS scores had a greater proportion surviving than those with BACU >5 ng/mL (P = .03) and dogs with severe (3-4) RLS scores (P = .04). All dogs with a BACU <5 ng/mL or mild RLS score were alive at last follow-up (median, 365 days; range, 44-365 days). In all, 68.1% of other dogs survived to 2 months (95% CI, 54.8%-84.8%). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with lower BACU and RLS scores have improved survival; however, it is unclear what specific cutoffs should be used for prognosis.

Multiple variants in XDH and MOCOS underlie xanthine urolithiasis in dogs.

Hereditary xanthinuria is a rare autosomal recessive disease caused by missense and loss of function variants in the xanthine dehydrogenase (XDH) or molybdenum cofactor sulfurase (MOCOS) genes. The aim of this study was to uncover variants underlying risk for xanthinuria in dogs. Affected dogs included two Manchester Terriers, three Cavalier King Charles Spaniels, an English Cocker Spaniel, a Dachshund, and a mixed-breed dog. Four putative causal variants were discovered: an XDH c.654G > A splice site variant that results in skipping of exon 8 (mixed-breed dog), a MOCOS c.232G > T splice site variant that results in skipping of exon 2 (Manchester Terriers), a MOCOS p.Leu46Pro missense variant (Dachshund), and a MOCOS p.Ala128Glyfs*30 frameshift variant that results in a premature stop codon (Cavalier King Charles Spaniels and English Cocker Spaniel). The two splice site variants suggest that the regions skipped are critical to the respective enzyme function, though protein misfolding is an alternative theory for loss of function. The MOCOS p.Leu46Pro variant has not been previously reported in human or other animal cases and provides novel data supporting this residue as critical to MOCOS function. All variants were present in the homozygous state in affected dogs, indicating an autosomal recessive mode of inheritance. Allele frequencies of these variants in breed-specific populations ranged from 0 to 0.18. In conclusion, multiple diverse variants appear to be responsible for hereditary xanthinuria in dogs.