To assess heritability and mode of inheritance for hereditary equine regional dermal asthenia (HERDA) in Quarter Horses.
1,295 horses with Quarter Horse bloodlines, including 58 horses affected with HERDA.
Horses were classified as affected or unaffected or as undetermined when data were insufficient to assess phenotype. Pedigree data were analyzed to determine the probable mode of inheritance. Heritability was estimated by use of Bayesian statistical methods.
Heritability (mean+/-SD) of HERDA was estimated to be 0.38+/-0.13, with both sexes having an equal probability of being affected. Results for evaluation of the pedigrees were consistent with a single Mendelian autosomal recessive mode of inheritance.
HERDA in Quarter Horses is an inherited disease, and affected horses are more likely to produce affected offspring. An autosomal recessive mode of inheritance should be considered by people making breeding decisions involving Quarter Horses when a first-degree relative has been confirmed with HERDA or has produced affected offspring. In addition, breeders whose horses have produced affected offspring can reduce the likelihood of producing affected horses in the future by avoiding inbreeding.
"Although the mouse model recapitulates clinical features of the human disease, the phenotypes observed seem not to provide additional insights into the disease pathogenesis from what is already known of the disease affecting the human yet. Further, a missense G31R mutation in CyPB/PPIB was found in the horse to cause the degenerative skin disorder, HERDA, without changes in skeletal or collagen being reported (Tryon et al., 2005). Hence, additional studies are needed to understand what physiological substrate(s) are directly impaired by the loss of CyPB/PPIB function and promote disease pathogenesis. "
[Show abstract][Hide abstract] ABSTRACT: Despite remarkable advances in human genetics and other genetic model systems, the fruit fly, Drosophila melanogaster, remains a powerful experimental tool to probe with ease the inner workings of a myriad of biological and pathological processes, even when evolutionary forces impart apparent divergences to some of such processes. The understanding of such evolutionary differences provides mechanistic insights into genotype-phenotype correlations underpinning biological processes across metazoans. The pioneering work developed by the William Pak laboratory for the past four decades, and the work of others, epitomize the notion of how the Drosophila system breaks new fertile ground or complements research fields of high scientific and medical relevance. Among the three major genetic complementation groups produced by the Pak's laboratory and impairing distinct facets of photoreceptor neuronal function, the nina group (ninaA, …., ninaJ) selectively affects the biogenesis of G protein-coupled receptors (GPCRs), mediating the photoconversion and transduction of light stimuli. Among the nina genes identified, ninaA arguably assumes heightened significance for several reasons. First, it presents unique physiological selectivity toward the biogenesis of a subset of GPCRs, a standalone biological manifestation yet to be discerned for most mammalian homologues of NinaA. Second, NinaA belongs to a family of proteins, immunophilins, which are the primary targets for immunosuppressive drugs at the therapeutic forefront of a multitude of medical conditions. Third, NinaA closest homologue, cyclophilin B (CyPB/PPIB), is an immunophilin whose loss-of-function was found recently to cause osteogenesis imperfecta in the human. This report highlights advances made by studies on some members of immunophilins, the cyclophilins. Finally, it reexamines critically data and dogmas derived from past and recent genetic, structural, biological, and pathological studies on NinaA and few other cyclophilins that support some of such paradigms to be less than definite and advance our understanding of the roles of cyclophilins in cell function, disease, and therapeutic interventions.
Journal of neurogenetics 02/2012; 26(2):132-43. DOI:10.3109/01677063.2011.647143 · 1.27 Impact Factor
"Hereditary equine regional dermal asthenia is an autosomal recessive dermatological condition of Quarter Horses and related crosses (Tryon et al. 2005). Though in some reports the condition has been referred to as " hyperelastosis cutis', this terminology has been discouraged as the defect does not appear to be in the elastic fibers (White et al. 2004). "
[Show abstract][Hide abstract] ABSTRACT: The objective of this review is to introduce equine clinicians to the rapidly evolving field of clinical genomics with a vision of improving the health and welfare of the domestic horse. For 15 years a consortium of veterinary geneticists and clinicians has worked together under the umbrella of The Horse Genome Project. This group, encompassing 22 laboratories in 12 countries, has made rapid progress, developing several iterations of linkage, physical and comparative gene maps of the horse with increasing levels of detail. In early 2006, the research was greatly facilitated when the US National Human Genome Research Institute of the National Institutes of Health added the horse to the list of mammalian species scheduled for whole genome sequencing. The genome of the domestic horse has now been sequenced and is available to researchers worldwide in publicly accessible databases. This achievement creates the potential for transformative change within the horse industry, particularly in the fields of internal medicine, sports medicine and reproduction. The genome sequence has enabled the development of new genome-wide tools and resources for studying inherited diseases of the horse. To date, researchers have identified 11 mutations causing 10 clinical syndromes in the horse. Testing is commercially available for all but one of these diseases. Future research will probably identify the genetic bases for other equine diseases, produce new diagnostic tests and generate novel therapeutics for some of these conditions. This will enable equine clinicians to play a critical role in ensuring the thoughtful and appropriate application of this knowledge as they assist clients with breeding and clinical decision-making.
"HERDA ist eine Krankheit, die vor allem bei Quarter Horses und verwandten Rassen beschrieben und die mit einer Mutation im PPIB Gen assoziiert ist (Scott und Miller, 2003; White et al., 2004; Tryon et al., 2005; Tyron et al., 2007). PPIB codiert die Peptidyl-Prolyl cis-trans-Isomerase (Synonym Cyclophilin B), ein essentielles Enzym für die Faltung der Pro--Ketten zum tripelhelikalen Prokollagen (Steinmann et al., 1991). "
[Show abstract][Hide abstract] ABSTRACT: Hereditäre equine dermale Asthenie (HERDA) ist eine autosomal rezessive Hautkrankheit, die vor allem junge Quarter Horses und verwandte Rassen betrifft. Die Symptome sind charakterisiert durch leichte Verletzbarkeit und erhöhte Dehnbarkeit der Haut, meist in der Satelllage. Die Prognose ist vorsichtig zu stellen, denn die Pferde können nicht normal zum Reiten eingesetzt werden und müssen oft euthanasiert werden. Beim Quarter Horse ist HERDA mit einer Mutation im Cyclophilin B Gen (PPIB) assoziiert. Cyclophilin B ist ein Enzym, welches für die Tripelhelixbildung von Kollagen wichtig ist. Wir beschreiben hier eine Schweizer Jährlings-Stute mit Symptomen von HERDA, aber ohne Mutation im PPIB Gen und bei der auch Ehlers-Danlos Typ IV, Typ VI, Typ VIIA, Typ VIIB und Typ VIIC (Dermatosparaxis) als ätiologische Ursache ausgeschlossen werden konnten.
Hereditary equine dermal asthenia (HERDA) is an autosomal recessive skin disease that affects predominantly Quarter Horses and related breeds. Typical symptoms are easy bruising and hyperextensible skin on the back. The prognosis is guarded, as affected horses cannot be ridden normally and are often euthanised. In the Quarter Horse, HERDA is associated with a mutation in cyclophilin B (PPIB), an enzyme involved in triple helix formation of collagen. Here we describe the case of a Swiss Warmblood filly with symptoms of HERDA without PPIB-mutation and in which we also could exclude Ehlers-Danlos syndrome Type IV, VI, VIIA, VIIB and VIIC (dermatosparaxis type) as etiological diseases.
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