{"id":2458,"date":"2020-10-12T21:46:13","date_gmt":"2020-10-12T21:46:13","guid":{"rendered":"https:\/\/www.rmhorse.com\/?p=2458"},"modified":"2020-10-12T21:46:52","modified_gmt":"2020-10-12T21:46:52","slug":"multiple-congenital-ocular-anomalies-mcoa","status":"publish","type":"post","link":"https:\/\/www.rmhorse.com\/?p=2458","title":{"rendered":"Multiple Congenital Ocular Anomalies (MCOA)"},"content":{"rendered":"<p><b>Genetic Survey of the PMEL17\/ Silver Mutation Which Causes<span class=\"Apple-converted-space\">\u00a0<\/span><\/b><b>Multiple Congenital Ocular Anomalies (MCOA)<\/b><\/p>\n<p><em>Prepared by<span class=\"Apple-converted-space\">\u00a0<\/span>Noah Anderson<\/em><br \/>\n<em>Chair, Genetics Committee RMHA<\/em><br \/>\n<em>Assistant Professor of Biology<\/em><br \/>\n<em>Winona State University<\/em><\/p>\n<p>**This is an excerpt from the report;\u00a0<a href=\"https:\/\/www.rmhorse.com\/wp-content\/uploads\/2020\/10\/MCOA-REPORT-FINAL-oct.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">read the entire report here**<\/a><\/p>\n<h4>What do we know about MCOA?<span class=\"Apple-converted-space\">\u00a0<\/span><\/h4>\n<ol>\n<li>It is 100% caused by a gene called PMEL17, which also causes the silver (chocolate) coat coloration (Andersson et al., 2013).<span class=\"Apple-converted-space\">\u00a0<\/span><\/li>\n<li>The eye abnormalities are more common and severe in homozygous silver (Z\/Z) horses.<span class=\"Apple-converted-space\">\u00a0 <\/span>These include but are not limited to: retinal detachment, retinal dysplasia, large, protrusive corneas (pop eyes), dysfunctional pupils that lack typical pupillary response, cataracts, and myopia (near-sightedness: Ramsey et al., 1999). <span class=\"Apple-converted-space\">\u00a0<\/span><\/li>\n<li>Horses that are heterozygous (Z\/N) for silver typically have no major eye abnormalities, instead, they present with fluid filled cysts within the eye.<span class=\"Apple-converted-space\">\u00a0 <\/span>Studies have not been able to determine what effect, if any, cysts have on the eyesight of the horse.<span class=\"Apple-converted-space\">\u00a0 <\/span>Currently, they are thought to be benign. <span class=\"Apple-converted-space\">\u00a0<\/span><\/li>\n<li>To date, only myopia (near-sightedness) has been shown to be progressive component of MCOA; Evidence of which has been found in silver Icelandic horses older than 16 years (Johansson et al. 2017).<span class=\"Apple-converted-space\">\u00a0 <\/span>Other defects have been found to be stable over the horse\u2019s lifetime (Bellone, 2017). <span class=\"Apple-converted-space\">\u00a0<\/span><\/li>\n<li>Lastly, it is important to remember that not all eye problems are caused by MCOA.<span class=\"Apple-converted-space\">\u00a0 <\/span>Horses, just like humans, can acquire or develop eye problems. <span class=\"Apple-converted-space\">\u00a0<\/span><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Genetic Survey of the PMEL17\/ Silver Mutation Which Causes\u00a0Multiple Congenital Ocular Anomalies (MCOA) Prepared by\u00a0Noah Anderson Chair, Genetics Committee RMHA&#8230;<\/p>\n","protected":false},"author":1,"featured_media":2459,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_price":"","_stock":"","_tribe_ticket_header":"","_tribe_default_ticket_provider":"","_tribe_ticket_capacity":"0","_ticket_start_date":"","_ticket_end_date":"","_tribe_ticket_show_description":"","_tribe_ticket_show_not_going":false,"_tribe_ticket_use_global_stock":"","_tribe_ticket_global_stock_level":"","_global_stock_mode":"","_global_stock_cap":"","_tribe_rsvp_for_event":"","_tribe_ticket_going_count":"","_tribe_ticket_not_going_count":"","_tribe_tickets_list":"[]","_tribe_ticket_has_attendee_info_fields":false,"footnotes":""},"categories":[3],"tags":[],"class_list":["post-2458","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/posts\/2458","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2458"}],"version-history":[{"count":2,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/posts\/2458\/revisions"}],"predecessor-version":[{"id":2461,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/posts\/2458\/revisions\/2461"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=\/wp\/v2\/media\/2459"}],"wp:attachment":[{"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2458"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2458"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rmhorse.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2458"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}