Page 574 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

558 PART 7 ■ Principles and Disorders of Hemostasis and Thrombosis

I an inherite e ciency is i enti e , a unctiona assay is or because o ro uction o a ys unctiona o ecu e, which

re erre . T e re erre etho o ana ysis is chro ogenic is known as ty e II e ciency state.

assay. A ow FXIII eve oes not istinguish e ciency ro Acquire actor X e ciency is co on an can be

a ow va ue ue to FXIII autoantibo ies. cause by

Prothrombin Group ■ Lack o vita in K (so e newborns are born with vita in

K e ciency)
T e actors in the rothro bin grou ( actors II, VII, IX, an Severe iver isease

X) are vita in K e en ent in or er to be unctiona . A ■ Bui u o abnor a roteins in the tissues an organs

o these actors contain the (ga a)-carboxyg uta ic aci – ■ (a y oi osis)

rich region, the GLA domain, that is critica or the ca ciu - Use o rugs such as war arin

bin ing ro erties o these roteins. ■

Factor X ay be associate with a co bine inherite
Factor II (Prothrombin) e ciency o FVII. T ree genetic utations can occur in

T is is a rare inherite b ee ing isor er. Sy to s can be genes VKCFD, GGCX, an VKORC1. Heterozygotes ost

i to o erate. A though it is inherite as an autoso a o en re ain asy to atic or have on y a i b ee ing

recessive, it ay a so be acquire . wo ty es o actor II e - ten ency.

ciency exist: ty e I hy o rothro bine ia an qua itative Laboratory n ings inc u e activate artia thro bo-

ty e II ys rothro bine ia. astin ti e (AP ) rothro bin ti e ( ), an Russe ’s

In this e ciency, the activate artia thro bo astin vi er veno ti e (RVV ), which are ro onge . B ee ing

ti e (AP ) an rothro bin ti e (P ) are usua y ro- ti e is within the re erence range. Resu ts o actor X

onge . T e thro bin ti e ( ) an b ee ing ti e tests are assays ay vary, e en ing on whether the e ciency is

nor a . ty e I or ty e II. In atients with a ty e I e ciency, both

Another isor er o rothro bin is the prothrombin unctiona an antigenic actor X are ecrease . In atients

20210a utation. First re orte in 1996 as a a i ia cause o with a ty e II X e ciency, the unctiona eve is ecrease

venous thro boe bo is (V E), the prothrombin 20210a an the antigenic eve varies ro within the re erence

utation resu ts in increase eve s o as a rothro - range to a ecrease eve o ro uction o ys unctiona

bin an a concurrent increase risk or the eve o ent o actor X.

thro bosis. T e exact echanis o this isor er has not I a actor X e ciency is the on y actor e ciency, assays

been iscovere . Prothrombin 20210a has an esti ate rev- o other vita in K– e en ent c otting actors shou be

a ence o 2% in whites. nor a . I a actor X e ciency is ue to vita in K e ciency

Patients with the prothrombin 20210a utation have a or the resence o a vita in K antagonist, the eve s o other

two- to three o increase risk or eve o ing thro bosis. vita in K– e en ent c otting actors ( actor II, actor VII,

Te prothrombin 20210a utation can be i enti e without actor IX, actor X, an rotein C wi be a ecte .

DNA ana ysis. Te contact group. As the na e i ies, this grou requires

contact with a negative y charge sur ace or activation.
Factor VII (Labile Factor) T ese actors ( actors XI, XII, reka ikrein (F etcher actor)

T is autoso a recessive actor e ciency is known as an HMWK (Fitzgera actor)) are invo ve in the intrin-

A exan er’s isease. Sy to s range ro asy to atic sic coagu ation athway. T ey are o erate y stab e an are

to inor an ajor b ee er or s. S ontaneous thro bosis not u y consu e uring coagu ation an can be oun in

ay be resent. wo or s o actor VII e ect are qua ita- o erate a ounts in seru .

tive ty e 1 an quantitative ty e II. Mutations in actor VII

an actor V genes or a co bine V an VII e ciency are Factor XI

LMAN1 an MCFD2. A e ciency o actor XI is re erre to as he o hi ia C,

T is is the on y actor e ciency where on y the rothro - as a thro bo astin antece ent (P A) e ciency, or

bin ti e (P ) is ro onge . Stan ar actor assay unctiona Rosentha syn ro e, a so ca e Miescher-Me kersson-

an i uno ogic rovi es a e nitive iagnosis. Rosentha syn ro e. T is genetic e ect is an autoso a

recessive trait that occurs re o inant y in eo e o Jewish
Factor X, FX (Stuart-Prower Factor) Ashkenazi (Euro ean) heritage.

T is is an autoso a recessive or acquire isor er. T is is- It is an asy to atic or i isor er characterize by

or er is one o the wor ’s ost rare actor e ciencies. It easy bruising, e istaxis, an he orrhage in conjunction with

exists in i , o erate, an severe or s. Wo en with ac- trau a. B ee ing ani estations in he o hi ia C o not cor-

tor X e ciency ay rst be iagnose when they have very re ate with the actor XI eve .

heavy enstrua b ee ing an b ee ing a er chi birth. T e Laboratory screening e onstrates an abnor a activate

con ition ay be rst notice in newborn boys i they have artia thro bo astin ti e (AP ) an a nor a rothro -

b ee ing that asts onger than nor a a er circu cision. bin ti e (P ). T e AP is nor a in heterozygotes with a

Factor X e ciency ay arise because o re uce synthe- i e ciency. He arin wi inter ere with test resu ts. Lu us

sis o the rotein, which is known as ty e I e ciency state, anticoagu ants (LA) ay inter ere with test resu ts.