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Genetic Linkage of P8 and K1
How can you figure out the chances of different genotypes when breeding horses? Monohybrid Cross It’s easy for one gene. Let’s say that there is a stallion that has one copy of one of the genetic variants associated with PSSM2, the P2 variant (MYOT-S232P). This stallion is heterozygous (n/P2), meaning that he has one normal…
Read MoreThe K1 Genetic Variant Affects COL6A3, a Gene Encoding a Collagen
Contents Introduction The K1 genetic variant that has been part of EquiSeq’s Myopathy Panel since October 2019 is a missense allele of COL6A3, a gene encoding a collagen [1]. Collagens are a family of proteins that are the main structural components of the connective tissue. Collagens also guide bone formation and play an important role in…
Read MoreThe P8 Genetic Variant Affects PYROXD1, a Gene Required for Oxidative Defense
Contents Introduction The P8 genetic variant that has been part of EquiSeq’s Myopathy Panel since October 2019 is a missense allele of PYROXD1, a gene required for oxidative defense [1]. Mutations of the human PYROXD1 gene are associated with Myofibrillar Myopathy 8 in humans [1]. The P8 allele of equine PYROXD1 changes an aspartic acid (D) to a histidine (H),…
Read MorePeer Review Fails to Identify Errors in Inconclusive Study of Genetic Variants of Equine Muscle Genes
This blog post is a discussion of a paper published by Williams et al. in a recent issue of Equine Veterinary Journal [1]. The paper aims to identify genetic variants that might be responsible for Myofibrillar Myopathy (MFM) in Warmbloods. The authors use a candidate gene approach, searching for variants of eight of the nine genes known…
Read MoreGenetic Basis of Exercise Intolerance in Arabians
Paul Szauter, PhD, Chief Scientific Officer of EquiSeq, gave a presentation titled “Genetic Basis of Exercise Intolerance in Arabians” at the Al Khamsa Annual Meeting and Convention in Fayetteville, Arkansas on October 13, 2019. EquiSeq is a company based in Albuquerque, New Mexico, that develops and sells genetic tests for horses. Exercise intolerance is known…
Read MoreThe Px Allele of CACNA2D3 May Affect Splicing of a Component of the Voltage-Gated Calcium Channel
A Genome Wide Association Study (GWAS) of Recurrent Exertional Rhabdomyolysis (RER) identified a region on chromosome 16 as the only part of the genome associated with RER [1]. One of the populations in the study showed an association between RER and five Single Nucleotide Polymorphisms (SNPs) that define a 71.6 kb interval within the 822…
Read MoreMechanism of muscle damage in filaminopathy
Several recent studies address the mechanism of muscle damage in filaminopathy. Filaminopathy is a term that describes muscle disorders resulting from mutations in the FLNC gene, which encodes filamen C. Two different clinical disease states are included in filaminopathy: Myofibrillar Myopathy 5 (MFM5) and Distal Myopathy 4 (DM4). Studies on the mechanism of muscle damage in filaminopathy…
Read MoreGenetic Linkage of P2 and P4
How can you figure out the chances of different genotypes when breeding horses? Monohybrid Cross It’s easy for one gene. Let’s say that there is a stallion that has one copy of one of the genetic variants associated with PSSM2, the P2 variant (MYOT-S232P). This stallion is heterozygous (n/P2), meaning that he has one normal…
Read MoreFilamin C (FLNC)
Filamins are a family of actin-binding proteins. In humans and other mammals, there are three filamins: filamin A, filamin B, and filamin C. Filamins A and B are widely expressed, while filamin C expression appears limited to skeletal and cardiac muscle. The figure below (adapted from [1]) shows the domain structure of filamin C. Filamins…
Read MoreP3 Allele of FLNC is Associated with Myofibrillar Myopathy in Horses
In human patients, mutations in the gene encoding filamin C (FLNC) are associated with Myofibrillar Myopathy 5 [1]. In a prior blog post, we reviewed the human mutations in FLNC associated with the disease state Myofibrillar Myopathy 5 (MFM5) and various cardiomyopathies. We also presented the specific changes associated with the equine P3 allele of…
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