Clinical Pediatric Hematology-ncology Volume 21 ㆍ Number 1 ㆍ pril 2014 RIGINL RTICLE 가능성있는폰빌레브란트병의유병률에대한연구 이명숙 1 ㆍ김동빈 1 ㆍ김순기 2 ㆍ유기영 3 ㆍ김희진 4 ㆍ이선호 5 ㆍ박상규 1 1 울산대학교병원소아청소년과, 2 인하대학교병원소아청소년과, 3 한국혈우재단, 4 삼성의료원진단검사의학과, 5 울산대학교병원진단검사의학과 Myoung Sook Lee, M.D. 1, Dong in Kim, M.D. 1, Soon Ki Kim, M.D. 2, Ki Young Yoo, M.D. 3, Hee Jin Kim, M.D. 4, Sun Ho Lee, M.D. 5 and Sang Kyu Park, M.D. 1 1 Department of Pediatrics, Ulsan University Hospital, Ulsan, 2 Department of Pediatrics, Inha University Hospital, Incheon, 3 Korea Hemophilia Foundation, 4 Department of Laboratory Medicine, Samsung Medical Center, Seoul, 5 Department of Laboratory Medicine, Ulsan University Hospital, Ulsan, Korea ackground: Definition of possible von Willebrand disease (VWD) included levels of von Willebrand factor antigen (VWF:g) or von Willebrand factor ristocetin cofactor activity (VWF:RCo) below 30 U/dL. The purpose of this study was to determine the prevalence of possible VWD in Ulsan, Korea. We also analyzed the influence of demographic factors such as age, gender, and blood group on subject levels of VWF. Methods: etween March 2011 and September 2011 we prospectively investigated 1,039 subjects (271 children, 768 adults). lood samples were collected for the determination of VWF:g, VWF:RCo, and factor VIII coagulation assay (FVIII:C). standardized questionnaire was administered to evaluate hemorrhagic symptoms at the time of first examination, using a bleeding score ranging from 0 to 3. Results: Forty five subjects met the criteria for possible VWD, for a prevalence of 4.3%. Subjects of Group had a significantly lower mean FVIII:C, VWF:g, and VWF:RCo value than subjects of group,, or (P<0.001). Conclusion: ur results suggest that the prevalence of VWD may be much higher than previously reported. Efforts to increase the awareness and diagnosis of VWD may help improve identification of patients with bleeding disorders and lead to early, appropriate management with safe and efficacious therapies. Key Words: von Willebrand disease, Prevalence, Ulsan pissn 2233-5250 / eissn 2233-4580 http://dx.doi.org/10.15264/cpho.2014.21.1.16 Clin Pediatr Hematol ncol 2014;21:16 22 Received on March 14, 2014 Revised on pril 1, 2014 ccepted on pril 8, 2014 This study was approved by the institutional review board of Ulsan University Hospital (2011016). Corresponding uthor: Sang Kyu Park Department of Pediatrics, Ulsan University Hospital, angeojin Soonwhandoro 877, Dong-gu, Ulsan 682-714, Korea Tel: +82-52-250-7060 Fax: +82-52-250-8071 E-mail: sang@uuh.ulsan.kr 서론폰빌레브란트병 (von Willebrand Disease, VWD) 은 1926년 Erik von Willebrand에의해처음보고된유전출혈질환으로혈우병와함께가장흔한유전출혈질환으로알려져있다 [1]. 외국에서는출혈질환센터에등록된환자수를근거로계산한폰빌레브란트병의유병률은 0.004-0.01% 에불과했으며, 일반인구를대상으로출혈증상, 낮은폰빌레브란트인자 (von Willebrand factor, VWF), 가족력이있는사람을선별검사한유병률은발표자에따라 0.6% 에서 1.3% 로다양하게보고되었다 [2-6]. 현재까지국내에서는폰빌레브란트병유병률에대 16
한연구가발표된바가없으며, 2012년한국혈우재단혈우병백서에따르면혈우병 환자는 1,579명이등록되어있으나, 폰빌레브란트병환자는겨우 98명이등록되어있는실정이다 [7]. 저자들은우리나라의폰빌레브란트병유병률조사의기초자료를얻기위하여 1,086명의소아및성인을대상으로폰빌레브란트병진단의검사기준인폰빌레브란트인자항원 (von Willebrand factor antigen, VWF:g) 및리스토세틴보조인자활성도 (von Willebrand factor ristocetin cofactor acticity, VWF:RCo) 가 30 U/dL 미만의가능성있는폰빌레브란트병 (possible von Willebrand disease) 의유병률과 VWF:g, VWF:RCo가혈액형, 연령, 성별에따라서다른지를알아보고자하였다. 또한설문조사를실시하여출혈력을조사하였다. 대상및방법 1) 대상 2011년 3월부터 2011년 8월까지검사를한 1,086명중에서혈액형을모르거나, 설문조사가미흡한 47명을제외하였다. 19세이하의소아는울산대학교병원에서수술전검사를하는환자와소아청소년과외래방문환자및입원환자중에서감 Table 1. leeding score used in the study Symptoms Epistaxis Cutaneous symptoms Minor wounds ral cavity bleeding Gastrointestinal bleeding Muscle hematomas or hemarthrosis Tooth extraction (most severe episode) Surgery (most severe episode) Menorrhagia Postpartum hemorrhage ssigned score 2 = packing, cauterization 3 = transfusion, replacement 1 = petechiae or bruises 2 = hematomas 3 = medical consultation (1-5 episodes year -1 ) 3 = surgery/blood transfusion 3 = surgery/blood transfusion 3 = surgery/blood transfusion 3 = transfusion, intervention 2 = suturing or packing 3 = transfusion 2 = suturing or resurgery 3 = transfusion 2 = consultation, pill use, iron therapy 3 = transfusion, hysterectomy, dilatation-curettage, replacement therapy, iron therapy 2 = blood transfusion, dilation-curettage, suturing 3 = hysterectomy Clin Pediatr Hematol ncol 17
Myoung Sook Lee, et al 염및염증질환이없는환자 271명을대상으로하였으며, 성인은자발적으로검사를원하는 768명으로총 1,039명을대상으로전향적으로조사를하였다. 경구피임약복용중, 임신중인여성과검사 3시간이내에격한운동을한대상은제외하였다. 2) 출혈점수를위한설문조사설문조사는 2005년 Rodeghiero 등이개발한출혈력과출혈점수를위한설문조사를이용하였다 [8]. 코피, 피부증상, 경미한상처에의한출혈, 구강출혈, 위장관출혈, 근육혹은관절출혈, 발치후출혈, 수술후출혈, 월경과다및산후출혈에대하여각각 0에서 3까지등급을매긴후합산하여출혈점수를산정하였다 (Table 1). 세가지이상의출혈증세가있거나출혈점수가남자는 4점, 여자는 6점이상일때의미있는출혈력이있다고판정하였다. 3) VIII인자활성도 (factor VIII coagulation assay, FVIII:C), VWF 의측정연구대상자의말초혈액 6 cc를안정된상태에서채취하였고, 3.2% sodium citrate가함유된시험관을사용하였다. 채취된검체는 3,000 rpm에서 10분간원심분리하여혈장을분리한후 -80 o C에보관하였다. VWF:g과 VWF:RCo의측정은 HemosIL TM VWF:g, VWF:RCo (Instrumentation Laboratory Co., edford, M, US) 를사용하여 automated latex enhanced immunoassay 방법으로측정하였다. FVIII:C의측정은 HemosIL TM FVIII deficient plasma (Instrumentation Laboratory Co., edford, M, US) 를사용하여 human plasma immunodepleted of factor VIII 방법으로측정하였다. 4) 직접염기서열분석법에의한 VWF 유전자의돌연변이검출 VWF:g 및 VWF:RCo가모두 30 U/dL 미만인대상중에서유전자검사에동의한 8명의말초혈액의백혈구에서 Wizard Genomic DN Purification Kit (Promega, Madison, WI, US) 를사용하여제작사의프로토콜에따라 DN를추출하였다. 추출된 DN 검체로 VWF 유전자의모든엑손 (exons) 과그인접부위염기서열을증폭할수있도록저자들이직접제작한시동체 (primer) 를사용하여 thermal cycler (Model 9700; pplied iosystems, Foster City, California, US) 에서중합효소연쇄반응 (polymerase chain reaction, PCR) 을시행하였다. PCR 산물 (amplicon) 로동일한시동체를이용하여 igdye Terminator Cycle Sequencing Ready Reaction kit (pplied iosystems, Rotkreuz, Switzerland) 를이용하여염기서열분석기 (I Prism 3130 Genetic nalyzer, pplied iosystems) 에서직접염기서열분석실험을시행하였다. 얻은연구대상자의염기서열파일을 VWF 유전자의표준염기서열 (NT_009759.16, NM_000552.3) 과함께소프트웨어 (Sequencher 4.10.1, Gene Codes Corporation, nn rbor, MI, US) 로분석하여유의한변이 (variation) 를검출하고, 검출된변이를 HGVS (Human Genome Variation Society) 의권고 (http://www.hgvs.org/mutnomen/) 에따라기술하였다. 5) 가능성있는폰빌레브란트병 (possible VWD) VWF:g 혹은 VWF:RCo의농도가 30 U/dL 미만이면가능성있는폰빌레브란트병 (possible VWD) 으로정의하였다 [9]. 6) 통계적방법성별, 소아, 성인, 혈액형에따른 FVIII:C, VWF:g, VWF:RCo 평균값의차이는 t-test로검증했으며, FVIII:C, VWF:g, VWF:RCo의상관관계는 Pearson correlation coefficient를사용하였다. 나이가 VWF:g, VWF:RCo에미치는영향은 simple regression 분석을시행하였다. 통계적유의성은 P값이 0.05 미만인경우로하였다. 모든통계분석은 SPSS (version 21, Chicago, IL, US) 와 R package (version 3.0.2, R foundation for statistical computing, Vienna, ustria) 로시행하였다. 결과 1) 연령및성별 19세이하의소아는 271명, 성인은 768명이었으며남자가 Table 2. Main characteristics of the population studied N (%) Males (%) s (%) Mean age, range (y) Children ( 19 y) dults Total 271 (26.1) 768 (73.9) 1,039 135 (39.5) 207 (60.5) 342 136 (19.5) 561 (80.5) 697 7.7, 0-19 34.2, 20-86 27.7, 0-86 18 Vol. 21, No. 1, pril 2014
342 명, 여자가 697 명이었다 (Table 2). 2) 혈액형에따른 FVIII:C, VWF:g, VWF:RCo 농도 혈액형의분포는 형 360 명 (34.6%), 형 285 명 (27.4%), 형 122명 (11.7%), 형 272명 (26.2%) 으로일반적인한국인의혈액형분포와일치하였다 (Table 3). 형의 FVIII:C, VWF:g, VWF:RCo 농도는 형, 형, 형에서의수치보다모두의미있게낮았다 (Table 4). 3) 연령및성별에따른 FVIII:C, VWF:g, VWF:RCo 농도 Table 3. Distribution of blood group in 1,039 subjects lood group N (%) Total 360 (34.6) 285 (27.4) 122 (11.7) 272 (26.2) 1,039 남자가여자보다 FVIII:C, VWF:g, VWF:RCo의농도가모두의미있게높았으며소아가성인보다 FVIII:C, VWF:g, VWF:RCo의농도가모두의미있게높았다 (Table 5). 19세이하에서는나이와 VWF:g, VWF:RCo 농도가역상관관계를보였으나 20세이상에서는나이와 VWF:g, VWF:RCo 농도가높은상관관계를보였다 (Fig. 1-4). Table 4. Mean values of FVIII:C, VWF:g, and VWF:RCo according to the blood group lood group N FVIII:C (U/dL, CI 95%) VWF:g (U/dL, CI 95%) VWF:RCo (U/dL, CI 95%) 360 285 122 272 71.5 (68.5-74.6) 73.4 (68.5-74.6) 73.5 (68.2-79.2) 56.9 (54.0-60.1) 86.0 (82.2-90.0) 89.5 (85.3-93.8) 94.2 (87.8-101.0) 70.9 (66.6-75.3) 76.0 (72.7-79.4) 77.1 (73.6-80.7) 82.2 (76.7-88.2) 57.5 (54.4-60.8) The differences were significant as follows: vs,,, P<0.001. CI, confidence interval. Table 5. Mean values of FVIII:C, VWF:g, and VWF:RCo according to the gender and the age N FVIII (U/dL, CI 95%) VWF:g (U/dL, CI 95%) VWF:RCo (U/dL, CI 95%) Male Children ( 19 y) dult 342 697 271 768 71.2 a) (67.9-74.7) 66.6 a) (64.4-68.9) 79.2 b) (75.2-83.5) 64.5 b) (62.5-66.6) 91.0 b) (86.9-95.4) 76.7 b) (74.1-79.3) 94.3 b) (89.3-99.7) 76.9 b) (74.5-79.4) 79.6 b) (76.1-83.3) 68.0 b) (65.7-70.2) 86.8 b) (82.5-91.3) 66.9 b) (64.8-68.9) CI, confidence interval. a) P<0.05, b) P<0.001. Fig. 1. Inverse correlation between age ( 19 y) and VWF:g. Fig. 2. Correlation between age ( 20 y) and VWF:g. Clin Pediatr Hematol ncol 19
Myoung Sook Lee, et al Fig. 3. Inverse correlation between age ( 19 y) and VWF:RCo. Fig. 4. Correlation between age ( 20 y) and VWF:RCo. Table 6. Characteristics of 45 possible VWD ge 19 y 20 y Gender Male lood type VWF:RCo/VWF:g <0.7 0.7 N (%) 5 (1.8) 40 (5.2) 5 (1.5) 40 (5.7) 13 (3.6) 5 (1.8) 1 (0.8) 26 (9.6) 15 (33.3) 30 (66.6) Table 7. Characteristics of 30 who have significant bleeding score (more than two symptoms or score > 3 or 5 in males and females) ge 19 y 20 y Gender Male lood type N (%) 7 (2.8) 23 (2.9) 4 (1.2) 26 (3.7) 9 (2.5) 10 (3.5) 2 (1.6) 9 (2.5) Table 8. Data of the patients for whom candidate implicated mutations of VWF gene were found No Gender ge lood type FVIII:C VWF:g VWF:RCo mino acid substitution (nucleotide substitution) leeding score 1 2 3 4 24 24 26 20 41.8 34.1 33.1 27.3 23.7 26.1 29.1 28.3 22.5 26.6 24.8 27.3 R1527W (4579C>T), new mutation T789 (2365>C) G1351D (4052G>), new mutation T789 (2365>C) 1 1 0 0 4) 가능성있는폰빌레브란트병 (possible VWD) VWF:g 및 VWF:RCo가 30 U/dL 미만은 45명 (4.3%) 이며남자는 5명 (1.5%), 여자는 40명 (5.7%) 이었다. 소아는 5명 (1.8%), 성인은 40명 (5.2%) 이었다. 혈액형 형은 13명 (3.6%), 형은 5명 (1.8%), 형은 1명 (0.8%), 형은 26명 (9.6%) 이었다. 45명중 15명 (33.3%) 이 VWF:RCo/VWF:g의비가 0.7 미만이었다 (Table 6). 5) 출혈점수 30명 (2.9%) 에서의미있는출혈력이있었으며남자는 4명 (1.2%), 여자는 26명 (3.7%) 이었다. 소아는 7명 (2.8%), 성인은 23명 (2.9%) 이었다 45명의가능성있는폰빌레브란트병에서는출혈력이있는사람이한명도없었다 (Table 7). 출혈증상이 3개이상은 2.8% 로 Rodeghiero의연구의정상군의 0.5% 와는차이가없었으나필연보인자 (obligatory carrier) 의 50% 에비 20 Vol. 21, No. 1, pril 2014
하여의미가있게적었다. 6) 유전자검사결과 VWF 유전자검사를한 8명중 2명은기존에발표된돌연변이가있었으며 2명에서는새로운돌연변이가발견되었다. 4명에서는돌연변이가발견되지않았다 (Table 8). 고찰국내에서는혈우재단에 1,579명이등록되어있는혈우병 환자에비하여폰빌레브란트병환자는 98명만이등록되어있는실정이다. 2011년세계혈우병연맹의조사에의하면 2,628 명의혈우병 환자가보고된 ustralia의경우 1,966명의 VWD 환자가보고되어있는것과는큰차이를보인다 [10]. 미국의경우 2010년에혈우병가 13,000여명이고, VWD 역시 13,000여명으로보고하였다 [11]. 일본의경우혈우병 5,446명에비하여 984명이등록되어있는것과비교하여도현저히적은숫자이다 [10]. 이는우리나라에서 VWD 환자가제대로진단되지않고있거나혹은전국적인통계가이루어지지않고있음을의미한다. 특히질환의특성상, 보통때는임상적증상을별로보이지않기때문에혈우재단에등록하는환자가적을것으로사료된다. 폰빌레브란트병에대한진단기준은다양하게많으나 2000년캐나다토론토의소아아동병원 (the Hospital for Sick Children, HSC) 에서개발한진단기준과 2006년에발표된세계혈전지혈학회 (the International Society on Thrombosis and Haemostasis, ISTH) 의진단기준이널리사용되고있다 [9,12]. HSC 진단기준은 VWF:g 및 VWF:RCo 가기준치보다낮으면서의미가있는점막피부출혈및폰빌레브란트병의가족력이있는경우, ISTH 진단기준은낮은농도의 VWF:g 및 VWF:RCo, 의미가있는점막피부출혈과폰빌레브란트병의가족력및 VWF 유전자의돌연변이가있으면확정폰빌레브란트병 (definite VWD) 으로정의하였다. 그러나대부분의환자에서이상의기준을충족하는경우가드물어서 HSC 진단기준은 VWF:g 및 VWF:RCo가기준치보다낮은경우, ISTH 진단기준은낮은농도의 VWF:g 및 VWF:RCo와의미가있는점막피부출혈및폰빌레브란트의가족력이있으면가능성있는폰빌레브란트병 (possible VWD) 으로정의하였다. 본연구를시행한울산지역에는등록된폰빌레브란트병환자가한명뿐이어서본연구에참여한대상자중가족력이있는대상자가한명도없으므로 HSC 기준의가능성있는폰빌레브란트병유병률을조사하였다. 낮은농도의 VWF:g 과 VWF:RCo 기준치도다양하나본연구에서는 2007년미국 국립보건원심장폐혈액연구원 (National Heart, Lung, and lood Institute) 에서발표한지침서에따라서 VWF:g 및 VWF:RCo 농도가 30 U/mL 미만을낮은농도의 VWF:g 및 VWF:RCo로정의하였다 [13]. H 항원의당화의차이로인하여 혈액형이혈장 VWF의주중재자로알려져있는데 [14], 본연구에서도 형의 FVIII:C, VWF:g, VWF:RCo 농도가 형, 형, 형의수치보다모두의미있게낮았다 (Table 4). 남자가여자보다 FVIII:C, VWF:g, VWF:RCo의농도가모두의미있게높아서 Werner 등의결과와일치하는데, 이는호르몬의영향과스트레스때문이라고알려져있다 [5,15,16]. 소아가성인보다 FVIII:C, VWF:g, VWF:RCo의농도가모두의미있게높았으며 (Table 5), 19세이하에서는나이와 VWF:g, VWF:RCo 농도가역상관관계를보였다 (Fig. 1, 3). 이는나이가어릴수록혈액채취를할때스트레스로인하여 VWF의농도가증가하기때문이다 [17]. 따라서소아에서폰빌레브란트병의진단시에는 VWF의농도가정상이거나경계에있더라도판정에신중해야한다. 또한 20세이상에서는나이와 VWF:g, VWF:RCo 농도가높은상관관계를보여 (Fig. 2, 4) iron 등의결과와일치하였으며 VWF의농도를판단할때나이도고려하여야함을암시한다 [6]. VWF:g 및 VWF:RCo가 30 U/dL 미만인가능성있는폰빌레브란트병은 45명 (4.3%) 이며이중남자는 5명 (1.5%), 여자는 40명 (5.7%), 소아는 5명 (1.8%), 성인은 40명 (5.2%) 이었다. 혈액형 형은 13명 (3.6%), 형은 5 명 (1.8%), 형은 1명 (0.8%), 형은 26명 (9.6%) 으로성인여자, 형에서유병률이높았다 (Table 6). VWF:RCo/VWF:g 의비가 0.7 미만이면전체폰빌레브란트환자의 20-30% 를차지하는제2형폰빌레브란트병의가능성이높은데, 45명중 15명 (33.3%) 이 VWF:RCo/VWF:g의비가 0.7 미만이었다. Rodeghiero 등은출혈력조사가폰빌레브란트병의진단에민감도 69.1%, 특이성 98.6% 를보여폰빌레브란트병진단을위하여혈액검사를해야되는대상을선별하는데에유용하다고하였으나본연구에서는출혈력이있는 30명중에 (Table 7) 한명도가능성있는폰빌레브란트병이없어폰빌레브란트병선별검사로서출혈력조사의유용성에의문이든다 [8]. 따라서앞으로우리나라에서폰빌레브란트병으로확진된환자들을대상으로출혈력조사를하여출혈력조사의유용성을평가해야한다고사료된다. 폰빌레브란트병필연보인자 42명중 15명이의미가있는출혈증상이없었는데이중 6명이진단후수혈을받는등의의미있는출혈이있었다는보고가있으므로본연구에서의가능성있는폰빌레브란트병 45명은수술, 출산시에세밀한관찰이필요하다 [8]. Clin Pediatr Hematol ncol 21
Myoung Sook Lee, et al 제 1형폰빌레브란트병의약 65% 에서유전자돌연변이가있으며이중 60% 는과오돌연변이에의한것이다 [18]. 또한제1형폰빌레브란트병가족의유전자연관분석결과 70% 에서표현형과유전자사이에연관성이있었다 [19]. 따라서폰빌레브란트병진단에유전자검사를함으로써정확도를높일수있다. 본연구에서는 VWF:g, VWF:RCo가모두 30 U/dL 미만인 23명중에서 8명에서유전자검사를한결과 2명은기존에발표된돌연변이가있었으며 2명에서는새로운돌연변이가발견되었다. 우리나라의폰빌레브란트병유병률조사의기초자료를얻기위하여 1,086명의소아및성인을대상으로출혈력조사와 VWF:g 및 VWF:RCo가 30 U/dL 미만의가능성있는폰빌레브란트병의유병률을조사한결과가능성있는폰빌레브란트병의유병률은 4.3% 이었다. 현재등록된 98명의폰빌레브란트병환자보다는훨씬많은환자들이진단을받지못하여큰수술이나출산시에발생할수있는대량출혈의위험에노출되어있다고생각된다. 따라서이연구를토대로전국적인폰빌레브란트병의유병률에대한연구가필요하며폰빌레브란트병에대한관심과진단을높여서안전하고효과적인치료를하여야한다. 감사의글 This study was supported by a 2011 grant from the Korea Hemophilia Foundation, Seoul, Korea; and from axter Pharmaceutical Co., Ltd, 2011. 참고문헌 1. von Willebrand E. Hereditar pseudohemofili. Fin Lakaresallsk Handl 1926;67:87-112. 2. loom L. The von Willebrand syndrome. Semin Hematol 1980;17:215-27. 3. Nilsson IM, Holmberg L. Von Willebrand's disease today. Clin Haematol 1979;8:147-68. 4. Rodeghiero F, Castaman G, Dini E. Epidemiological investigation of the prevalence of von Willebrand's disease. lood 1987;69:454-9. 5. Werner EJ, roxson EH, Tucker EL, Giroux DS, Shults J, bshire TC. Prevalence of von Willebrand disease in children: a multiethnic study. J Pediatr 1993;123:893-8. 6. iron C, Mahieu, Rochette, et al. Preoperative screening for von Willebrand disease type 1: low yield and limited ability to predict bleeding. J Lab Clin Med 1999;134:605-9. 7. Korea Hemophilia Foundation. 2012 nnual report. Seoul: Korea Hemophilia Foundation, 2012:16. 8. Rodeghiero F, Castaman G, Tosetto, et al. The discriminant power of bleeding history for the diagnosis of type 1 von Willebrand disease: an international, multicenter study. J Thromb Haemost 2005;3:2619-26. 9. Dean J, lanchette VS, Carcao MD, et al. von Willebrand disease in a pediatric-based population--comparison of type 1 diagnostic criteria and use of the PF-100 and a von Willebrand factor/collagen-binding assay. Thromb Haemost 2000;84:401-9. 10. World Federation of Hemophilia. Report on the nnual Global Survey 2011. Montreal, C: World Federation of Hemophilia, 2013. (ccessed ctober 28, 2013, at http://www1. wfh.org/publications/files/pdf-1488.pdf) 11. aker JR, Riske, Drake JH, et al. US Hemophilia Treatment Center population trends 1990-2010: patient diagnoses, demographics, health services utilization. Haemophilia 2013;19: 21-6. 12. Sadler JE, udde U, Eikenboom JC, et al. Update on the pathophysiology and classification of von Willebrand disease: a report of the Subcommittee on von Willebrand Factor. J Thromb Haemost 2006;4:2103-14. 13. US Department of Health and Human Services, National Instititues of Health, National Heart, Lung, and lood Institute. The diagnosis, evaluation, and management of von Willebrand disease. ethesda, MD: NHLI Health Information Center, 2007. (ccessed June 16, 2009, at http://www.nhlbi. nih.gov/guidelines/vwd/vwd.pdf) 14. Sodetz JM, Paulson JC, McKee P. Carbohydrate composition and identification of blood group,, and H oligosaccharide structures on human Factor VIII/von Willebrand factor. J iol Chem 1979;254:10754-60. 15. lperin J. Estrogens and surgery in women with von Willebrand's disease. m J Med 1982;73:367-71. 16. loom L. von Willebrand factor: clinical features of inherited and acquired disorders. Mayo Clin Proc 1991;66:743-51. 17. Laffan M, rown S, Collins PW, et al. The diagnosis of von Willebrand disease: a guideline from the UK Haemophilia Centre Doctors' rganization. Haemophilia 2004;10:199-217. 18. Lillicrap D. Genotype/phenotype association in von Willebrand disease: is the glass half full or empty? J Thromb Haemost 2009;7 Suppl 1:65-70. 19. Eikenboom J, Van Marion V, Putter H, et al. Linkage analysis in families diagnosed with type 1 von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 VWD. J Thromb Haemost 2006;4:774-82. 22 Vol. 21, No. 1, pril 2014