A domestic cat whole exome sequencing resource for trait discovery.

Over 94 million domestic cats are susceptible to cancers and other common and rare diseases. Whole exome sequencing (WES) is a proven strategy to study these disease-causing variants. Presented is a 35.7 Mb exome capture design based on the annotated Felis_catus_9.0 genome assembly, covering 201,683 regions of the cat genome. Whole exome sequencing was conducted on 41 cats with known and unknown genetic diseases and traits, of which ten cats had matching whole genome sequence (WGS) data available, used to validate WES performance. At 80 × mean exome depth of coverage, 96.4% of on-target base coverage had a sequencing depth > 20-fold, while over 98% of single nucleotide variants (SNVs) identified by WGS were also identified by WES. Platform-specific SNVs were restricted to sex chromosomes and a small number of olfactory receptor genes. Within the 41 cats, we identified 31 previously known causal variants and discovered new gene candidate variants, including novel missense variance for polycystic kidney disease and atrichia in the Peterbald cat. These results show the utility of WES to identify novel gene candidate alleles for diseases and traits for the first time in a feline model.

[Management of urethral stones in dogs using pneumatic and laser lithotripsy]. / Management von Urethralsteinen beim Hund mittels pneumatischer und laserenergetischer Lithotripsie.

OBJECTIVE: Description of clinical experience with two different lithotripsy modalities for treatment of urethral stones in dogs. MATERIAL AND METHODS: Retrospective analysis (October 2016 - November 2017) of medical records from dogs with urinary stones that underwent transurethral pneumatic or laser lithotripsy. RESULTS: In 28 male and 5 female dogs, either pneumatic lithotripsy (39 %) or laser lithotripsy (61 %) was performed. In the urethra, stone free rates of 100 % in females and over 85 % in males could be achieved using either fragmentation modality. In 3 of 28 (11 %) male dogs, after fragmentation of urethral stones, urethral patency was impaired because of endoscopically suspected polypoid urethritis requiring urethrostomy. In 8 out of 28 (29 %) male dogs and in 1 of 5 (20 %) female dogs, an additional lithocystotomy was necessary to achieve stone-free status in the lower urinary tract. CONCLUSION AND CLINICAL RELEVANCE: Transurethral pneumatic or laser lithotripsy of urinary stones is a successful procedure in dogs. Major pathological conditions of the urethral mucosa may require further surgical or interventional methods for the restoration of a functional urethra.

[Diagnostic value of the BRAF variant V595E in urine samples, smears and biopsies from canine transitional cell carcinoma]. / Diagnostische Aussagekraft der BRAF-Mutation V595E in Urinproben, Ausstrichen und Bioptaten beim kaninen Übergangszellkarzinom.

OBJECTIVE: Transitional cell carcinoma (TCC) is the most common malignant tumour of the canine urinary tract. Previously, the mutation of the BRAF gene V595E was identified in approximately 85 % of canine TCC cases by DNA sequencing of TCC tumour cells, both in frozen and paraffin-embedded tissue sections, as well as in urine. The objective of this study was to establish these methods in cytological smears and to investigate the prevalence of BRAF mutation V595E in canine TCC in our cohort of patients. MATERIAL AND METHODS: Biopsy samples (n = 43), urine (n = 48) and/or cytological smears (n = 31) from 66 dogs with TCC (n = 33), urinary bladder polyps (n = 7), cystitis (n = 23) or without bladder diseases (n = 3), submitted for routine diagnostics, were selected. DNA isolation from paraffin material, urine and cytological smears was performed using commercially available kits. Exon 15 was examined for the presence of the BRAF mutation c.1784T>A by Sanger sequencing. RESULTS: In 39/43 paraffin-embedded biopsies and 38/48 urine samples, a sufficient amount of good quality DNA was isolated. DNA isolation and sequencing were successful in 16/18 smears with a high cell count, but not in the 10/13 smears with low cellularity. In all cases from which different sample materials were available, the results of BRAF analysis were identical in paraffin-embedded tissue, cytological smears and/or urine. In 22/31 dogs (70.9 %) with TCC, the presence of the BRAF mutation was confirmed, whereas it could not be detected in animals without pathological findings or with cystitis or with a polyp. CONCLUSION AND CLINICAL RELEVANCE: BRAF mutation analysis is a new and good method to be able to mostly confirm a diagnosis of TCC in uncertain cases. Non-invasive diagnostic samples, including urine and urine sediment containing sufficient numbers of relevant cells as well as cytology aspirates and formalin-fixed biopsies can be used for analysis. However, it is important to note that only a positive identification of the mutation is diagnostic. Further research is necessary to investigate prognostic and therapeutic relevance of the variant and how this genetic analysis can be used as an early detection method for TCC.