Progressive retinal atrophy (PRA) in dogs is characterised by the degeneration of the photoreceptor cells of the retina, resulting in vision loss and eventually complete blindness. The condition affects more than 100 dog breeds and is known to be genetically heterogeneous between breeds. Around 14 mutations have now been identified that are associated with PRA in around 49 breeds, but for the majority of breeds the mutation(s) responsible have yet to be identified. Using genome-wide association with 16 Gordon Setter PRA cases and 22 controls, we identified a novel PRA locus, termed rod-cone degeneration 4 (rcd4), on CFA17 (Praw  = 2.22 × 10(-8) , Pgenome  = 2.00 × 10(-5) ), where a 3.2-Mb region was homozygous within cases. A frameshift mutation was identified in C2orf71, a gene located within this region. This variant was homozygous in 19 of 21 PRA cases and was at a frequency of approximately 0.37 in the Gordon Setter population. Approximately 10% of cases in our study (2 of 21) are not associated with this C2orf71 mutation, indicating that PRA in this breed is genetically heterogeneous and caused by at least two mutations. This variant is also present in a number of Irish Setter dogs with PRA and has an estimated allele frequency of 0.26 in the breed. The function of C2orf71 remains unknown, but it is important for retinal development and function and has previously been associated with autosomal recessive retinitis pigmentosa in humans.

Drawing on an assumption of the co-construction of the material and the social, late-onset Alzheimer's disease (AD) is used as an illustrative example to assess claims for an emergent figure of the "individual genetically at risk." Current medical understanding of the genetics of AD is discussed, followed by a summary of media and AD society materials that reveal an absence of gene hype in connection with this disease. Excerpts from interviews with first-degree relatives of patients diagnosed with AD follow. Interviewees hold complex theories of causation. After genetic testing they exhibit few if any subjective changes in embodied identity or lifestyle. Family history is regarded by interviewees as a better indicator of future disease than is genetic testing. We argue that, even when molecular genetics are better understood, predictions about complex disease based on genotyping will be fraught with uncertainty, making problematic the concept of individuals as genetically at risk when applied to late-onset complex disease.

Background Data about congenital sensorineural deafness (CSD) in white blue‐eyed cats derive mainly from research colonies, and information about client‐owned cats is limited. Objectives To describe the prevalence of CSD in a client‐owned population of white purebred kittens and colored littermates in the United Kingdom. Animals One hundred thirty‐two solid white client‐owned purebred kittens and 61 colored littermates, 6 to 21 weeks of age. Methods Retrospective (56 cases) and prospective (137 cases) study. Hearing was assessed by brainstem auditory evoked response testing, and the entire litter was tested. Results Congenital sensorineural deafness was diagnosed only in solid white kittens, with a prevalence of 30.3% (15.9% bilateral, 14.4% unilateral). The prevalence of CSD was significantly higher in white kittens with 1 (44.4%) or 2 (50%) blue irises than in those without blue irises (22.2%). Kittens with at least 1 blue iris were 3.2 times more likely to have CSD than kittens without blue irises. In solid white kittens, CSD was diagnosed in 7 of 15 (46.7%) Turkish Vankedisi, 8 of 18 (44.0%) Maine Coon, 18 of 41 (43.9%) Norwegian Forest, 3 of 11 (27.3%) British Shorthair, 2 of 12 (16.7%) Devon Rex, 2 of 12 (8.3%) Persian, 1 of 21 (4.8%) Russian, and 0 of 2 Sphinx. The prevalence of CSD was significantly different in Norwegian Forest, Maine Coon, and Turkish Vankedisi kittens compared with Persian or Russian kittens. Conclusion and Clinical Importance We identified a high prevalence of CSD in a population of client‐owned purebred white kittens in the United Kingdom and suggest differences in breed‐specific prevalence of CSD.

Associations between CSD and pigmentation patterns linked to the merle gene were demonstrated for Border Collies. Evidence for an inherited component to CSD in Border Collies supports selective breeding from only tested and normal parents to reduce the prevalence of this disease.

Using the genetics of late onset Alzheimer's disease (LOAD) as illustrative, this paper argues for a reflexive critique of the involved science, specifically in connection with estimations of increased risk. Following a review of social science commentary on genetic testing and screening in general, current scientific understanding about the molecular and population genetics of LOAD is then presented. The results of open-ended interviews conducted with first-degree relatives of individuals diagnosed with LOAD at two study sites follow. It is shown that the majority of people interviewed embrace the idea of complexity in connection with Alzheimer's disease causation and that many draw on a concept of “blended inheritance” with respect to the disease that “runs” in their family. It is argued that knowledge about risk obtained from genetic testing for LOAD rarely usurps other forms of understanding, but is nested by interviewees into previously held ideas about who in the family is most at risk for the disease.