This is Mary from Norway (1914-2002), the first patient described with “proaccelerin” (Factor V) deficiency. Since FXIII is the highest numbered coagulation factor (though there are more!) #HematologyTweetstory #13 is a (selective) tour of coag. factor names. Image: Stormorken./1 
Paul Arnor Owren (1905-1990) in Oslo evaluated Mary in 1943 for menorrhagia. She’d been almost blind since age 3 after an episode of epistaxis/syncope (?retinal hypoxia). Owren called her condition “parahemophilia” since surprisingly it manifest in a female w/ healthy brothers./2
Classical hemophilia had been recognized since ancient times. In the 12th century CE, for example, Maimonides wrote that circumcision should be avoided in boys if two of their brothers died due to hemorrhage- even if they were from different fathers (prescient, given X-linkage)/3
Before going into academic medicine, Owren lived in the countryside as a GP and farmed lucrative "platinum" foxes. With the onset of WW2 in 1939 & German occupation of Norway, the bottom dropped out of the exotic fox fur market, so Owren decided to moved to Oslo & do research./4
Paul Morawitz (1879-1936), coag pioneer in Tübingen, reported in 1905 that clotting required 4 factors: fibrinogen (later Factor I), prothrombin (II), “thrombokinase” (III;we know it as tissue factor) & calcium (IV). This was the concept Owren was working with 40 years later./5
Arman Quick’s widely used prothrombin time (1935) required mixing citrated patient plasma, rabbit brain thromboplastin, & calcium chloride. Mary’s plasma took 70s to clot instead of normal PT 11-13s. Mixing experiments showed her problem was something new, not prothrombin def./6
Back then scientists could perhaps be even more obnoxious to each other than they are today, if such is possible. After Owren published Mary's case in @TheLancet 1947, a nasty prolonged battle ensued with 2 other coag leaders, Quick @MedicalCollege & Wallace Seegers @waynestate.
Eventually - many years later - both Quick and Seegers conceded that indeed, Owren was on to something, and Mary's disease was due to a new coagulation factor deficiency. Here’s a faux newspaper announcing “concession” from Seegers that yes, Owren was right./8
We take for granted that coag factors are numbered. Imagine if they weren’t! It would be as much a mess as immunology markers would be if CD (Cluster of Differentiation/classification determinant) system hadn't come into place in the 1980s. Imagine having to memorize all those./9
One thing that bothered me in med school when first learning the coagulation cascade: what happened to Factor VI? We have Owren to blame for that. He described Factor VI as “accelerin” and FV as "proaccelerin", but VI turned out just to be activated Factor V, not a new factor./10
Nomenclature reflects history; history is messy. There are >20 Fanconi anemia genes, FANCA FANCB etc, but no FANCH or K (but 2 D’s – D1 and D2.) There’s coag protein C, but no A or B; AT3, but no AT1 or AT2. Vitamin B4 (choline) & B8 (biotin) exist but names not used. And so on.
Some other coag factors we now know only as numbers had interesting names when first described. Stuart-Prower Factor, now known as Factor X, was named after 2 patients. It was described by 2 groups independently in the 1950s, in a Ms. Audrey Prower & Mr. Rufus Stewart./12
Christmas Factor - AKA “plasma thromboplastin component”, Factor IX - was not only first described in a patient named Stephen Christmas (b1947 in London; he died of AIDS from plasma in 1993), it was first described in the Christmas issue of the @bmj_latest in 1952. (No joke😜)/13
Hemostasis expert Oscar Ratnoff in Cleveland described Hageman Factor – now called Factor XII. It's named after John Hageman, who needed surgery @UHhospitals-Case Western in 1953 for an ulcer... but the operation was postponed since his blood wouldn’t clot, at least in a tube./14
Hageman had previously tolerated surgeries, which illustrates how bleeding history is more important than coag tests in predicting surgical bleeding. He survived the ulcer, but 15 years later fell off a Penn Central railroad car, broke his hip & died while immobile... of a PE./15
There are many variant factor names too, eg #FactorVLeiden, first described in Dutch city of Leiden in 1994. Here I am enjoying the Dutch tradition of raw 'nieuwe haring' in Leiden (yes, I also had some without bread) on an enjoyable 2006 visit to college roommate @EricArnoys /16
Factor XIII, "fibrin stabilizing factor", was originally called Laki–Lorand factor after Hungarian-American biochemists Kalman Laki and Laszlo Lorand @NIH who proposed its existence in a 1948 @sciencemagazine letter and followup paper./17
There is actually a Factor XIV, XV, XVI, XVII, XVIII, XIX and so on – but these all have other names that are more widely used, like protein C, vWF, HMWK. @isth had a nomenclature committee to sort this out - not sure if it is still active, perhaps a fellow Twitter user knows.
Finally – one of the top 2 downloaded articles in the history of @ASHClinicalNews @ASH_Hematology is this one, “How I Teach The Coagulation Cascade”, by Dr Alice Ma @UNC_Health_Care. Enjoy! /19End ashclinicalnews.org/education/coag…
