242 Incidence of factor V Leiden and the prothrombin variant 20210 G→A in the Navarrese population: Preliminary studies in a group of Navarrese patients with venous thrombosis

POSTER PRESENTATIONS: Hereditary defects and polymorphisms

89

/

240 Changes in PAl-l, factor VII and fibrinogen by hormone replacement therapy are independent of promoter polymorphisms *DE MAAT MPM, *BLADBJERG E-M, **ANDERSEN LF, *GRAM J, *JESPERSEN J, and ***SKOUB Y SO *Dept. Clinical Biochemistt T, Ribe County Hospital and bTstitntefi." Thrombosis Research, South Jutland UniveJwitv Centre, Esbjerg, **Dept. Gynaecolo~, and Obstetrics, Rigshospitalet, Copenhagen, and ***Dept. Gvnaecology and Obstetricw, Frederiksberg Hospital, ~))penhagen, Denmark Background. Administration of oestrogens in hormone replacement therapy (HRT) arises changes in haemostasis factors, such as plasminogen activator inhibitor-1 (PAl-l), factor VII (FVll) and fibrinogen. It is assumed that these changes contribute to the decrease in cardiovascular events associated with HRT. Identifying subjects that will have a high or low response of these haemostasis factors when using HRT may ultimately reduce the thrombotic risk after menopause. Genetic variation in the promoter regions of PAl-I, FVII and fibrinogen is known to be associated with plasma levels of the respective proteins and with the regulation of the plasma phenotype. Methods. We studied if changes in PAl-1, FVII and fibrinogen plasma levels after 6 months of oral HRT administration (oestradiol 2 mg/day cyclic or continuously in combination with progestogen) to 53 women depend on the geno-

type of the PAl- 1 -675(4G/5G), the FVI1-323ins10 and the fibrinogen [3-gene 455G/A promoter polymorphisms. Blood was collected at baseline and after 6 months of HRT treatment for the determination of PAl-- I activity and antigen, FVII coagulant activity (FVII:C) and functional fibrinogen levels. Results. The association between the polymorphisms and the respective baseline plasma levels was: for PAI-I activity 8.8 IU/ml (4G4G, n=5), 1().0 IU/ml (4G5G, n=23) and 5.1 IU/ml (5G5G, n=l 1) (n.s.); for PAl- 1 antigen 17.0 ng/ml (4G4G, n=5), 15.2 ng/ml (4G5G, n=34) and 9.6 ng/ml 5G5G, n=l 1) (n.s.); for FVII:C 135% (0/0,n--45) and 104% (0/10+ 10/10,n= 15) (p < 0.001); and for fibrinogen 8.6 Hmol/1 (GG, n=30) and 8.3 prnol/I (GA,n= 12) (n.s.) (the first genotype mentioned is the homozygotes tbr the common 'allele). After 6 months on HRT the median changes in plasma levels of PAl activity (-5.8%, n.s.), PAl- 1 antigen (- 17%, p=0.01 ), fibrinogen (+6%, p < 0.01 ) and FVII:C (+7.4%, p---0.01) were independent of the respective promoter potymorphisms. However. the power of this study is low because the groups are small, and further studies in larger populations are needed.

Conclusion: In this study, the changes of PAl-1, FVII and fibrinogen plasma levels in women using HRT tot 6 months were independent of the promoter polymorphisms.

I

241 Studies on fibrinolysis in homozyous type I plasminogen deficiency *MINGERS A-M, **PHILAPITSCH A, *ZEITLER P, and *KRETH liVe" *University of Wiirzburg Children's ttospital, Wiirzhurg, Germany and **ttyland-lmmuno Division, Barter Healthcare. Vienna, Austria B a c k g r o u n d . Since our first o b s e r v a t i o n of h o m o z y g o u s type I plasm i n o g e n (Pig) d e f i c i e n c y in h u m a n s in 1994, we have treated several patients with this h e m o s t a t i c defect, all o f w h o m have c o n j u n c t i v i t i s lignosa (CL). S o m e of these patients also h a v e e x t r a o c u l a r pseudom e m b r a n o u s lesions o f m u c o u s m e m b r a n e s . N e i t h e r the patients nor their parents h a v e e x p e r i e n c e d t h r o m b o t i c e p i s o d e s . W e h y p o t h e s i z e d that c o m p e n s a t o r y m e c h a n i s m s i n d e p e n d e n t o f p l a s m i n o g e n - i n d u c e d f i b r i n o l y s i s m a y play a role. M e t h o d s . Six unrelated f e m a l e patients (aged 1 to 31 years) with hereditary Pig d e f i c i e n c y (5 h o m o z y g o t e s with P I g : A g and PIg:C b e l o w the limit o f detection, and 1 h e t e r o z y g o t e with P I g : A g 14% and PIg:C 2 0 % ) and their parents (n=12) w e r e tested. U s i n g i m m u n o l o g i c a l tests, w e d e t e r m i n e d p l a s m a levels o f P M N - e l a s t a s e in 6 patients with C L as well as in their parents. W e also tested m y e l o p e r o x i d a s e and metallo-

proteinase after infusion of L y s - P l a s m i n o g e n ( I m m u n o AG, Vienna, Austria) in one patient.

Results. P M N - e l a s t a s e l e v e l s in untreated h o m o z y g o u s patients r a n g e d from 88 to 335 n g / m l ( m e d i a n , 132 ng/ml); in the h e t e r o z y g o u s patient, 58 n g / m l ( n o r m a l = 20+_10 ng/ml). V a l u e s in 10 o f 11 parents tested r a n g e d from 42 to 110 n g / m l ( m e d i a n , 76 ng/ml). One m o t h e r with P l g : A g 6 0 % and PIg:C 8 6 % had 27 ng/ml. There w a s a pron o u n c e d d e c r e a s e in P M N - e l a s t a s e l e v e l s after p l a s m a e x c h a n g e in one patient as well as after r e p l a c e m e n t therapy with L y s - P l g in three patients with LC. H o w e v e r . n o r m a l l e v e l s were not reached. M y e l o p e r o x i d a s e a c t i v i t y was e l e v a t e d 30 rain after L y s - P l g infusion, and m e t a l l o p r o t e i n a s e d e c r e a s e d . No control values were a v a i l a b l e , however. C o n c l u s i o n s . T h e s e results are c o n s i s t e n t with our h y p o t h e s i s that other f i b r i n o l y t i c m e c h a n i s m s p r o b a b l y i n v o l v i n g P M N - e l a s t a s e or m e t a l l o p r o t e i n a s e also play a role in s e v e r e type I p l a s m i n o g e n deficiency.

/

242 Incidence of factor V Leiden and the prothrombin variant 20210 G-,A in the Navarrese population: Preliminary studies in a group of Navarrese patients with venous thrombosis *MONTES R, *ZABALEGUI N, **.4YAPE M, ***OR(JE M, ****PALOMA MJ, */*****P.4RAMO JA, and */*****ROCHA E *Laboratot3' of Vascular Biology and Thrombosis, School q/'Medicine, ~iversi~' r?/'Navarra, **Blood Bank o['Navarra, ***Hematolog3"Selvice, Hospital de Navarra, ****Hematology Seta,ice, Hospital Virgen del Camino. *****Hematolo~, Sela'ice, UnivetwiO, Clinic, University ~f Navarra, Pamplona, Spain Baekgrou nd. The factor V Leiden is the most common inheritedrisk factorfor venous thrombosis (VT) described so far. More recently,a sequencevariationin the 3"-untranslatedregionof the prothrombingene has been associatedwith an increasedrisk fi~rVT. The aim of this work is to analyze the incidence of both genetic variants in Navarra (Northern Spain) where people share a Basquegenetic background(Basques have been shown to be geneticallyquite difterent from the rest of Caucasoid populations).A prelinfiuarystudy with VT patients is performed to establish whether carrying such variants in our area increases the risk for VT. Methods. Genomic DNA samples from 269 Navarrese heahhy subjects and 64 consecutive and unselected Navarrese patients with VT were tested tot the presence of both mutations by PCR lbllowing the methods described by Bertina et al (Aature 1994;369:64-67) for factor V Leiden and by Poort et al (Bhmd 1996:88:3698-3703) for the 20210 G---->A mutation in the prothrombin gene.

Results. The incidence of the FV Leiden in the healthy population was 0.75% (allele frequency = 0.37%), which significantly increased in the patients group (incidence = 9.37%, allele frequency = 5.47%. p = 0.001 ). The incidence of the 20210 G---~Amutation in the prothrombin gene in the healthy population was 4.83% (allele frequency = 2.42%), which was not significantly higher (p = O. 16) in ehe patients groupalthough it increased to 9.37% (allele frequency = 4.69%). Interpretation. We tbund the incidence of the factor V Leiden mutation in the Navarrese populationto be lower than the observed in the rest of European populations,in agreement with a study by Lucotte & Mercier in French Basques where only 2 out of 198 subjects studied carded the mutation. The incidence of the 20210 G--->Amutation in the prothrombin gene in the Navarrese healthy population is the highest reported so far, although there are not as many availabledata as tbr factor V Leiden world distribution.The preliminarydata obtained with our group of patients indicate that carrying the factor V Leiden mutationundoubtedlyincreasesthe risk of developinga VT episode in our area. For the first time we describe that the frequencyof the 20210A allele of the prothrombin gene is not significantly higher in a VT patients group when compared with its healthy control population. However. the low number of patients included and the cleartendency towards a higher presenceof the mutation in VT patients make us suspect that this genetic variant will also constitute a risk factor for VT in our area.

Supported by grant 2209from Gobierno de Navarra.