Genetics of feline hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by an abnormal increase in myocardial mass that affects cardiac structure and function. HCM is the most common inherited cardiovascular disease in humans (0.2%) and the most common cardiovascular disease in cats (14.7%). Feline HCM phenotype is very similar to the phenotype found in humans, but the time frame for the development of the disease is significantly shorter. Similar therapeutic agents are used in its treatment and it has the same complications, such as heart failure, thromboembolism and sudden cardiac death. In contrast to humans, in whom thousands of genetic variants have been identified, genetic studies in cats have been limited to fragment analysis of two sarcomeric genes identifying two variants in MYBPC3 and one in MYH7. Two of these variants have also been associated with human disease. The high prevalence of the reported variants in non-affected cats hinders the assumption of their pathogenicity in heterozygotes. An in-depth review of the literature about genetic studies on feline HCM in comparison with the same disease in humans is presented here. The close similarity in the phenotype and genotype between cats and humans makes the cat an excellent model for the pathophysiological study of the disease and future therapeutic agents.     

Anatomy of avian rictal bristles in Caprimulgiformes reveals reduced tactile function in open-habitat,partially diurnal foraging species

Avian rictal bristles are present in many species of birds, especially in nocturnal species. Rictal bristles occur along the upper beak and are morphologically similar to mammalian whiskers. Mammalian whiskers are important tactile sensors, guiding locomotion, foraging and social interactions, and have a well-characterised anatomy. However, it is not yet known whether avian rictal bristles have a sensory function, and their morphology, anatomy and function have also not been described in many species. Our study compares bristle morphology, follicle anatomy and their association with foraging traits, across 12 Caprimulgiform species. Rictal bristle morphology and follicle anatomy were diverse across the 12 species. Nine of the 12 species had mechanoreceptors around their bristle follicles; however, there was large variation in their musculature, mechanoreceptor numbers and bristle morphology. Overall, species with short, thin, branching bristles that lacked mechanoreceptors tended to forage pre-dusk in open habitats, whereas species with mechanoreceptors around their bristle follicle tended to forage at night and in more closed habitats. We suggest that rictal bristles are likely to be tactile in many species and may aid in navigation, foraging and collision avoidance; however, identifying rictal bristle function is challenging and demands further investigation in many species.     

Serving those who serve: Psychotherapy with military clients

As in the Vietnam era, the wars in Iraq and Afghanistan are not the focus of the nightly news. Nevertheless, there are countless numbers of individuals enlisting, serving, deploying, redeploying, and leaving military branches every day. These individuals are underserved in many ways, especially after they end their formal relationship with their service. The purpose of this introduction is to describe the ongoing concerns and psychological problems of our military personnel and the efforts, described by the authors of papers in this issue, to address these concerns and problems.     

A phenotypically severe,biochemically “silent” case of HIBCH deficiency in a newborn diagnosed by rapid whole exome sequencing and enzymatic testing

3‐Hydroxyisobutyryl‐CoA dehydrogenase (HIBCH) deficiency is a rare error in valine catabolism associated with a Leigh syndrome‐like phenotype, mitochondrial dysfunction, and increased C4‐OH. We report the most severe case to date in a full‐term female who presented with poor feeding and nystagmus on day of life (DOL) 1. Although initial neuroimaging findings were concerning for metabolic disease, further metabolic testing was nondiagnostic and she was discharged on DOL 18. She was readmitted on DOL 22 after severe apneic episodes requiring intubation, with EEG demonstrating multifocal seizures and MRI/MRS demonstrating worsening findings. Care was withdrawn DOL 27 and she expired. Rapid whole exome sequencing (WES) demonstrated compound heterozygous variants in HIBCH with a paternal pathogenic variant (c.852delA, p.L284FfsX10 ) and a maternal likely pathogenic variant (c.488G>T, p.C163F). Fibroblast enzymatic testing demonstrated marked reduction in HIBCH levels. This case demonstrates the importance of rapid WES and follow‐up functional testing in establishing a diagnosis when metabolic disease is suspected but lacks an expected biochemical signature.