[Endoscopic treatment combined with extracorporeal shock wave lithotripsy of difficult bile duct stones]

OBJECTIVES

The aim of this study was to determine the safety and effectiveness of extracorporeal shock wave lithotripsy (ESWL) in difficult bile duct stones resistant to endoscopic extraction.

PATIENTS AND METHOD

From January 1997 to February 2002, combined treatment with endoscopy and ESWL was used in 19 patients who had undergone unsuccessful endoscopic bile duct stone extraction after sphincterotomy. The procedure was carried out using analgesic and sedative drugs or deep sedation, prophylactic antibiotic therapy, and monitoring of vital signs. Bile duct stone localization was performed by contrast injection through nasobiliary drainage and fluoroscopy. After each ESWL session, lavage was performed through drainage and stone fragments were extracted endoscopically.

RESULTS

The 19 patients presented high surgical risk due to advanced aged and/or concomitant diseases. All presented jaundice and pain and nine (47.3%) presented associated cholangitis. Thirty ESWL sessions were performed (1.57 sessions per patient), with a mean of 2,120 shock waves per session. In 16 of the 19 patients (84.2%), combined treatment with ESWL and subsequent instrumental endoscopic extraction achieved complete clearance of the biliary tract. The treatment failed in 3 patients who were referred for surgical treatment. No early or late complications were observed, except in one patient who presented a self-limiting febrile syndrome.

CONCLUSIONS

Therapeutic endoscopy combined with ESWL is safe and effective in patients with difficult bile duct stones. It represents a therapeutic alternative in patients at high surgical risk.

5'-p-Fluorosulfonylbenzoyl adenosine inhibits progesterone synthesis in human placental mitochondria

The human placental mitochondria have an ATP-diphosphohydrolase (apyrase) activity. In this paper we characterized the effect of 5'-p-fluorosulfonylbenzoyl adenosine (FSBA) on placental apyrase, and its repercussion on progesterone synthesis and oxygen consumption. Apyrase activity was inhibited by FSBA. Nucleosides tri- and diphosphates protected against FSBA inactivation, but divalent cations did not, indicating that FSBA attaches itself to an ATP-binding site of apyrase. In mitochondria, the inactivation of apyrase by FSBA was associated with inhibition of progesterone synthesis. Also, the oxygen consumption induced by ATP but not by ADP, was inhibited, clearly showing that FSBA exclusively inactivated the apyrase in human placental mitochondria. It is concluded that the apyrase activity is closely related to progesterone synthesis, probably associated with the cholesterol transport between mitochondrial membranes.

[Retreatment with interferon plus ribavirin in chronic hepatitis C patients with genotype 1 who had no response or a relapse with a previous interferon treatment. Long term follow-up]

The aims of this study were twofold: i) to evaluate the sustained response rate at 6 months, at 12 months and at the end of the follow-up [(46.39 +/- 9.74 months) (range: 6-60 months)] in patients with chronic hepatitis C retreated with interferon-a (IFN-a) plus ribavirin for 6 months (group A), 12 months (group B), in patients with relapse and those with no response to a previous course of monotherapy with IFN-a; and ii) to evaluate changes in the histological liver lesion. One hundred and four patients (100 with genotype 1 and four without), 44 with relapse and 60 non-responders, were included. A total of 20.2% of the patients were excluded because of side effects. Fifty percent of the relapsing patients with genotype 1 showed a sustained response. The sustained response rate was higher in group B than in group A, whereas the rate for the relapsing patients was lower in group B than in group A (13/20 vs. 5/16; 7.2% vs. 61.5%; p <0.09 and p <0.009, respectively). However, 9.3% of the non-responding patients showed a sustained response (A/B: 2/2). The relapsing patients who had a genotype other than 1 showed a sustained response. The sustained response rate was constant throughout the follow-up, except in relapsing patients from group A (the late relapse rate was 28.6%). The viral load was not related to the response. The grade and stage of the histological lesion improved in patients with sustained response (n=20) and in one-third of the non-responding patients (n=45) (p <0.0001 and p <0.0001). IFN in combination with ribavirin was more effective in relapsing patients with genotype 1 at 12 months than in those at 6 months of treatment, whereas the effectiveness in non-responding patients was low. The sustained response evaluation at 6 months was reliable, except in relapsing patients with 6 months of treatment. The histological lesion improved significantly with combination antiviral therapy.

Characterization of Lr46, a gene conferring partial resistance to wheat leaf rust

Components of resistance conferred by the Lr46 gene, reported as causing "slow rusting" resistance to leaf rust in wheat, were studied and compared with the effects of Lr34 and genes for quantitative resistance in cv. Akabozu. Lr34 is a gene that confers non-hypersensitive type of resistance. The effect of Lr46 resembles that of Lr34 and other wheats reported with partial resistance. At macroscopic level, Lr46 produced a longer latency period than observed on the susceptible recurrent parent Lalbahadur, and a reduction of the infection frequency not associated with hypersensitivity. Microscopically, Lr46 increased the percentage of early aborted infection units not associated with host cell necrosis and decreased the colony size. The effect of Lr46 is comparable to that of Lr34 in adult plant stage, but in seedling stage its effect is weaker than that of Lr34.

Partial resistance to leaf rust in a collection of ancient Spanish barleys

A collection of 569 Spanish barley accessions was screened for resistance to leaf rust (Puccinia hordei Otth) in the field at Córdoba during the 2000-2001 season. The level of resistance ranged from very low to very high. In 14% of the accessions the relative AUDPC (L94 = 100%) was lower than 10%. Selected accessions that were most resistant in the field, were tested in the seedling stage under controlled conditions. Macroscopic components of resistance indicated that six lines had a high level of partial resistance close to check cv. Vada and one line a similar level of partial resistance. Histological studies indicated that the resistance was based on a high percentage of early aborted colonies and reduction in colony size without plant cell necrosis. Three of the selected lines showed high percentage of plant cell necrosis associated with established colonies, which indicates a combination of prehaustorial resistance with late acting incomplete posthaustorial resistance. Although the new barley varieties already incorporate some partial resistance, new sources of partial resistance like these are needed to improve durability of the resistance.

Search for partial resistance to leaf rust in a collection of ancient Spanish wheats

A collection of 917 accessions of Spanish durum and bread wheat was screened for resistance to leaf rust (Puccinia triticina) under field conditions at three locations. Resistance levels ranged from very low to very high, high susceptibility being most frequent. Relative disease severity (referred to the most susceptible accession = 100%) was lower than 20% in about 6% of the accessions in each location. In the collection most of the lines (84%) displayed a susceptible infection type. A final selection of seven accessions (one of them durum) displaying low severity level in the field and high infection type in a growth chamber was chosen for further studies. High levels of partial resistant with longer latency period and high percentage of early aborted colonies without necrosis were found. They might be used in breeding programmes.

Characterization of Lr46, a gene conferring partial resistance to wheat leaf rust

Components of resistance conferred by the Lr46 gene, reported as causing "slow rusting" resistance to leaf rust in wheat, were studied and compared with the effects of Lr34 and genes for quantitative resistance in cv. Akabozu. Lr34 is a gene that confers non-hypersensitive type of resistance. The effect of Lr46 resembles that of Lr34 and other wheats reported with partial resistance. At macroscopic level, Lr46 produced a longer latency period than observed on the susceptible recurrent parent Lalbahadur, and a reduction of the infection frequency not associated with hypersensitivity. Microscopically, Lr46 increased the percentage of early aborted infection units not associated with host cell necrosis and decreased the colony size. The effect of Lr46 is comparable to that of Lr34 in adult plant stage, but in seedling stage its effect is weaker than that of Lr34.

Prenatal diagnosis in Rett syndrome

BACKGROUND/AIM

Rett syndrome (RTT) is an X-linked neurodevelopmental dominant disorder that affects almost exclusively girls. The disease is mainly sporadic, caused by de novo mutations at MECP2 gene (Xq28), but a low percentage of familial cases have been reported. We present the results of RTT prenatal diagnosis in three families and discuss the usefulness of such analyses in diseases caused mainly by de novo mutations.

METHODS

For adult individuals, DNA was extracted from peripheral lymphocytes; for fetus analysis it was obtained from cultured amniotic fluid or from chorionic biopsy specimens. Mutation detection at MECP2 gene was first carried out in the patients by SSCP/HD analysis and subsequent sequencing. Family studies and prenatal diagnoses were done by direct analysis of previously characterized patients' mutations using SSCP/HD or restriction analysis.

RESULTS

Heterozygous mutations identified in the 3 patients were: 1061del96bp, 473C-->T, and 763C-->T, respectively. Mutations were not present in the mothers' DNAs obtained from peripheral lymphocytes. None of the 3 fetuses analyzed carried the mutation of the affected sister.

CONCLUSIONS

Recurrence within RTT families can be due to asymptomatic nonpenetrant carrier mothers or to parental germinal mosaicism for the MECP2 mutation. Since germline mosaicism can neither be predicted nor detected, families with 1 affected patient whose RTT-causing mutation has been previously identified can benefit from prenatal diagnosis which contributes to a decrease in the recurrence risk in a new pregnancy comparable to that of the normal population.

Adenosine participates in regulation of smooth muscle relaxation in aortas from rats with experimental hypothyroidism

The contribution of adenosine receptors was evaluated in vascular relaxation in experimental hypothyroidism. Hypothyroid aortic rings contracted less than normal controls with noradrenaline, phenylephrine, and KCl; the difference was maintained after incubation with 1,3-dipropyl-8-p-sulfophenylxanthine (an A1 and A2 adenosine receptor blocker). The vascular relaxation induced by acetylcholine or carbachol was similar in normal and hypothyroid aortic rings. However, adenosine, N6-cyclopentyladenosine (an A1 adenosine receptor analogue), and 5'-N-ethylcarboxamidoadenosine (an A2 and A3 adenosine analogue) induced vasodilation that was larger in hypothyroid than in normal aortas. Nomega-nitro-L-arginine methyl ester shifted the dose-response curves of adenosine, N6-cyclopentyladenosine, or 5'-N-ethylcarboxamidoadenosine to the right in both normal and hypothyroid vessels. The blocker 1,3-dipropyl-8-p-sulfophenylxanthine significantly reduced adenosine-induced relaxation in the hypothyroid but not in the normal aortic vessels. These results suggest that in hypothyroid aortas, a larger adenosine-mediated vasodilation is observed probably due to an increase in receptor number or sensitivity.

Adverse effects of azathioprine in the treatment of inflammatory bowel disease

OBJECTIVE

To know the type, frequency and time course for the occurrence of adverse events in our series of patients with inflammatory bowel disease treated with azathioprine or 6-mercaptopurine.

PATIENTS AND METHOD

92 consecutive patients were treated with azathioprine. 70 of them (55 Crohn's disease, 14 ulcerative colitis and 1 undetermined colitis) were suitable for analysis.

RESULTS

We observed 23 adverse reactions in 21 patients. Adverse events were as follows: haematological 11.4%, digestive intolerance 11.4%, infection 7.1%, and pancreatitis 2.8%. The prevalence was increased among ulcerative colitis patients (57.8 vs. 21.8%) (p = 0.02). There were no statistical differences in the prevalence of adverse events respective of the age, gender or location of disease. Digestive intolerance and pancreatitis occurred within the first 6 months of therapy, whereas haematological side effects occurred between 3 months and 4 years after therapy onset. Early occurrence (but not late occurrence) was associated with thiopurine methyltransferase (TMPT) activity levels. All infections took place between 8 months and 5 years of treatment. Azathioprine was definitively withdrawn due to side effects in 9 cases (12.8%).

CONCLUSIONS

The frequency of adverse events in our study is similar to that reported in previous studies. Azathioprine withdrawal is required in almost half of the cases because of toxicity. Frequency of side effects is increased in patients with ulcerative colitis. The variability in time course makes clinical-biological monitoring mandatory.

Significant linkage and non-linkage of type 1 von Willebrand disease to the von Willebrand factor gene

Significant linkage of types 2A and 2B von Willebrand disease (VWD) to the von Willebrand factor (VWF) gene have been reported, as well as mutations in the VWF gene. However, data for the partial quantitative variant are less consistent. An inconsistency of association between the type 1 VWD phenotype and genotype has been reported recently. We undertook linkage analysis of 12 families with definite or possible type 1 VWD patients. One family with classic type 1 VWD had a high lod score (Z = 5.28, theta = 0.00). A total lod score of 10.68 was obtained for the four families with fully penetrant disease. In two families linkage was rejected, while three families did not show conclusive evidence of linkage. This study corroborates ABO blood group influence, especially in patients with mild deficiencies and/or incomplete penetrance. Indirect genetic analysis may be an option for diagnosing asymptomatic or presymptomatic type 1 VWD carriers, particularly in families showing higher penetrance. The study indicates defects of the VWF locus are to be expected in more than half of the families studied. However, as defects at different loci may be the cause of this phenotype, the results of the segregation analyses should be interpreted with caution, especially in studies involving small families, or mild expressions of the disorder or incomplete penetrance.

Albumin-derived advanced glycation end-products trigger the disruption of the vascular endothelial cadherin complex in cultured human and murine endothelial cells

Endothelial cell (EC) junctions regulate in large part the integrity and barrier function of the vascular endothelium. Advanced glycation end-products (AGEs), the irreversibly formed reactive derivatives of non-enzymic glucose-protein condensation reactions, are strongly implicated in endothelial dysfunction that distinguishes diabetes- and aging-associated vascular complications. The aim of the present study was to determine whether AGEs affect EC lateral junction proteins, with particular regard to the vascular endothelial cadherin (VE-cadherin) complex. Our results indicate that AGE-modified BSA (AGE-BSA), a prototype of advanced glycated proteins, disrupts the VE-cadherin complex when administered to ECs. AGE-BSA, but not unmodified BSA, was found to induce decreases in the levels of VE-cadherin, beta-catenin and gamma-catenin in the complex and in total cell extracts, as well as a marked reduction in the amount of VE-cadherin present at the cell surface. In contrast, the level of platelet endothelial cell adhesion molecule-1 (PECAM-1), which is located at lateral junctions, was not altered. Supplementation of the cellular antioxidative defences abolished these effects. Finally, the loss of components of the VE-cadherin complex was correlated with increases in vascular permeability and in EC migration. These findings suggest that some of the AGE-induced biological effects on the endothelium could be mediated, at least in part, by the weakening of intercellular contacts caused by decreases in the amount of VE-cadherin present.

Hidradenitis suppurativa and Crohn's disease: response to treatment with infliximab

Cutaneous manifestations occur frequently in inflammatory bowel disease. The association between hidradenitis suppurativa (HS) and Crohn's disease (CD) has been reported. We present a new case supporting this association. A dramatic improvement after treatment with infliximab was achieved for both refractory fistulizing CD and axillary HS.

Risk factors for high-order multiple implantation after ovarian stimulation with gonadotrophins: evidence from a large series of 1878 consecutive pregnancies in a single centre

BACKGROUND

High-order multiple pregnancies (triplets or more) have a large adverse impact on perinatal morbidity and mortality as well as important economic consequences. Most triplets and higher births are due to ovulation induction alone or in combination with intrauterine insemination (IUI) rather than to in-vitro fertilization (IVF). The present investigation was undertaken to determine whether there were specific variables that related to patient clinical characteristics (age of the woman, duration of infertility, type of infertility, body mass index, basal FSH and LH concentrations), treatment characteristics (initial dose of gonadotrophins, total dose of gonadotrophins administered, number of days of ovarian stimulation, insemination procedure, number of spermatozoa inseminated in patients undergoing IUI, type of luteal support), and ovarian response (oestradiol serum concentrations, number and size of follicles) that might be associated with the occurrence of high-order multiple implantation in order to develop a prediction model.

METHODS

This study employed univariate, multivariate and receiver-operating characteristic (ROC) analysis of a large series of 1878 consecutive pregnancies obtained in cycles stimulated with gonadotrophins. Of them, 1771 (94.3%) were low-order pregnancies (1477 singletons and 294 pairs of twins) and 107 (5.7%) were high-order pregnancies.

RESULTS

Predictive variables in the multivariate analysis were age of the woman, serum oestradiol concentrations and number of follicles >10 mm on the day of HCG injection. Stratification of the number of follicles into three categories (1 to 3, 4 to 5, and >5 follicles respectively), peak serum oestradiol and woman's age according to the ROC curves, showed that the risk of high-order multiple implantation correlated significantly with increasing total number of follicles and was significantly increased in women with a serum oestradiol >862 pg/ml and aged < or =32 years.

CONCLUSIONS

This three-variable model can help to identify patients at high-risk for high-order multiple pregnancy in ovulation induction cycles.

Trisomy rescue by postzygotic unbalanced (X;14) translocation in a girl with dysmorphic features

In this report we present the clinical features and molecular and cytogenetic findings in a female with partial trisomy 14q. Molecular and cytogenetic studies allowed us to determine that the extra 14q material (of paternal origin) was translocated postzygotically onto the maternal X chromosome. Consequently, only the derivative X chromosome was inactivated, although inactivation apparently did not spread over the entire chromosome 14q. This partial inactivation makes the present case unusual, giving rise to phenotypic features absent in other patients with partial trisomy 14q, typically restricted to the distal part of the chromosome.

Localization of non-specific X-linked mental retardation gene (MRX73) to Xp22.2

Clinical and molecular studies are reported on a family (MRX73) of five males with non-specific X-linked mental retardation (XLMR). A total of 33 microsatellite and RFLP markers was typed. The gene for this XLMR condition was been linked to DXS1195, with a lod score of 2.36 at theta = 0. The haplotype and multipoint linkage analyses suggest localization of the MRX73 locus to an interval of 2 cM defined by markers DXS8019 and DXS365, in Xp22.2. This interval contains the gene of Coffin-Lowry syndrome (RSK2), where a missense mutation has been associated with a form of non-specific mental retardation. Therefore, a search for RSK2 mutations was performed in the MRX73 family, but no causal mutation was found. We hypothesize that another unidentified XLMR gene is located near RSK2.

Analysis of phenolic constituents of biological interest in red wines by high-performance liquid chromatography

We describe a reversed-phase HPLC method that uses gradient elution and diode array detection to determine four biologically active phenolic constituents of red wines: gallic acid, trans-resveratrol, quercetin and rutin. The method permits direct injection without sample pre-treatment. ODS Hypersil served as the stationary phase; the gradient was formed by acetic acid, methanol, and water. Each analysis required an equilibration period of 10 min and a run time of 50 min for completion. Previously, total phenols were analysed according to the Folin-Ciocalteu method, using gallic acid as the standard, and the results are given as gallic acid equivalent.

The use of flow cytometry to assess membrane stability in fresh and cryopreserved trout spermatozoa

In this approach flow cytometry combined with PI was used as an alternative method to determined cell membrane integrity and osmotic fragility in trout spermatozoa. Milt was diluted 1:3 in a extender containing either 7% Me(2)SO or 7% Me(2)SO plus egg yolk-BSA and frozen in 0.5 ml French straws on a rack that floated 2 cm over the surface of liquid nitrogen. Cell integrity and membrane resistance to hyposmotic shock was analyzed before and after freezing/thawing. To test cell resistance to hyposmotic shock, sperm was subjected to hypo- and isosmotic solutions (10, 100, 300 mOsm/Kg) and cell integrity was analyzed through a time course (30 sec, 2, 5, 10 and 15 min) using propidium iodide and flow cytometry. This procedure allowed a rapid and accurate identification of different cell subpopulations according to their resistance to hyposmotic shock and, in this way, provides a method to evaluate the sub-lethal damage caused by cryopreservation. The proportion of extremely sensitive cells in fresh spermatozoa (2%) increased after cryopreservation: 30% without stabilizers, and 19% after the addition of egg yolk-BSA, demonstrating that external cryoprotectants significantly improved the resistance to the osmotic stress.

Association of the 3467C>T mutation (T1156M) in the von Willebrand's factor gene with dominant type 1 von Willebrand's disease

Type 1 is the most frequent form of von Willebrand's disease, which is characterized by a quantitative partial deficiency of von Willebrand's factor. At present, only two mutations located in the D3 domain (C1149R, C1130F) have been reported to cause the classic type 1 variant. The 3467C>T transition that predicts the T1156M amino acid change was detected in seven patients from one family and was not found in 110 normal alleles screened. This is a candidate mutation to cause dominant type 1 variant with complete penetrance. On the other hand, neither of the two mutations mentioned above has been detected in the other 15 families studied with type 1 or possible type 1 patients.

A new chloroplast envelope carbonic anhydrase activity is induced during acclimation to low inorganic carbon concentrations in Chlamydomonas reinhardtii

Using mass-spectrometric measurements of 18O exchange from 13C18O2 we determined the activity of carbonic anhydrase (CA; EC 4.2.1.1) in chloroplast envelope membranes isolated from Chlamydomonas reinhardtii cw-15. Our results show an enrichment of CA activity in these fractions relative to the activity in the crude chloroplast. The envelope CA activity increased about 8-fold during the acclimation to low-CO2 conditions and was completely induced within the first 4 h after the transfer to air levels of CO2. The CA-activity was not dissociated from envelope membranes after salt treatment. In addition, no cross-reactivity with other CA isoenzymes of Chlamydomonas was observed in our chloroplast envelope membranes. All these observations indicated that the protein responsible for this activity was a new CA isoenzyme, which was an integral component of the chloroplast envelopes from Chlamydomonas. The catalytic properties of the envelope CA activity were completely different from those of the thylakoid isoenzyme, showing a high requirement for Mg2+ and a high sensitivity to ethoxyzolamide. Analysis of the integral envelope proteins showed that there were no detectable differences between high- and low-inorganic carbon (Ci) cells, suggesting that the new CA activity was constitutively expressed in both high- and low-Ci cells. Two different high-Ci-requiring mutants of C. reinhardtii, cia-3 and pmp-1, had a reduced envelope CA activity. We propose that this activity could play a role in the uptake of inorganic carbon at the chloroplast envelope membranes.

Ultrasound-guided embryo transfer: immediate withdrawal of the catheter versus a 30 second wait

It is essential to deposit embryos as gently as possible during IVF, avoiding manoeuvres that might trigger uterine contractions which could adversely affect the results of this treatment. The time during which the embryo transfer catheter remains in the cervical canal might be related to stimulation of contractions. This study investigates the influence that the time interval before withdrawal of the catheter after ultrasound (US)-guided embryo deposit might have on the pregnancy rate in patients under IVF cycles. A total of 100 women about to undergo transfer of at least two optimal embryos was studied. The women were prospectively randomized into two groups: (i) slow withdrawal of the catheter immediately after embryo deposit (n = 51); and (ii) a 30 s delay before catheter withdrawal (n = 49). The pregnancy rates for transfer in the two groups were 60.8 and 69.4% respectively, with no significant differences. There were no statistically significant differences in pregnancy rates between the two patient groups. The results indicate either that the waiting interval was insufficient to detect differences, or that the retention time before withdrawing the catheter is not a factor that influences pregnancy rate.

Current understanding and management of chronic hepatosplenic suppurative brucellosis

To outline the characteristics and define appropriate management of chronic hepatosplenic suppurative brucellosis (CHSB), 905 patients with brucellosis were analyzed. Sixteen episodes of CHSB (14 in the liver and 2 in the spleen) were found in 15 patients. Six patients had had previous remote brucellosis. Twelve patients presented with systemic symptoms, and 12 with local symptoms. Cultures of blood samples yielded negative results in all cases except 1, and the results of cultures of pus specimens were positive for Brucella melitensis in only 2 cases. All patients showed calcium deposits surrounded by a hypodense area on computed tomography. Patients often had low titers of agglutinating antibody. In patients who were receiving conservative management, early response was successful in 50% and late response was successful in 33.3%. In the patients who underwent surgery and concomitant antibiotic therapy, early and late response was successful in 100%. Thus, CHSB mainly represents a local reactivation of previous brucellosis. Its diagnosis may be difficult to establish and surgery may be required to cure many patients.

New mutations in exon 28 of the von Willebrand factor gene detected in patients with different types of von Willebrand's disease

BACKGROUND AND OBJECTIVES

von Willebrand's disease (vWD), the most common hereditary bleeding disorder in humans, is caused by qualitative and/or quantitative deficiencies of von Willebrand factor, and can manifest itself under several different phenotypes. Most of the molecular defects have been detected in qualitative variants involving exon 28 of the vWF gene. Patients from four unrelated families with different types of vWD were included in the mutation screening of this region.

DESIGN AND METHODS

The whole exon 28 was analyzed in three gene specific fragments, two of them comprising the region involved in the platelet glycoprotein Ib vWF interaction. The search for mutations was carried out by single-stranded conformation polymorphism analysis. The mutations were then identified by automatic sequencing of the anomalous electrophoretic pattern samples.

RESULTS

The following candidate mutations were detected. The 3941T-->A transversion, which predicts the amino acid change V1314D, was detected in a sporadic patient with type 2B vWD and severe thrombocytopenia. The 4309G-->A transition, resulting in the amino acid substitution A1437T, was identified in four patients classified as having type 2M vWD. Six unclassified patients from another family carry the 4135C-->T mutation, which gives rise to a cysteine instead of the normal arginine (R1379C) that segregates with the phenotype. The amino acid change C1227R, predicted by the mutation 4135C-->T, was identified as a compound heterozygote in a patient with moderately severe type 1 vWD. None of these mutations had been described previously.

INTERPRETATION AND CONCLUSIONS

These findings confirm the importance already given to this region for the correct function of von Willebrand factor since the mutations detected, which affect the D3 and A1 domains, could give rise to different variants of the disease.