Case report: Asp194Ala variant in MFN2 is associated with ALS-FTD in an Italian family

Background: MFN2 gene encodes the protein Mitofusin 2, involved in essential mitochondrial functions such as fusion, trafficking, turnover, and cellular interactions. We describe a family carrying a novel MFN2 mutation associated with ALS-frontotemporal dementia (FTD) clinical phenotype in the mother and Charcot-Marie-Tooth disease type 2A (CMT2A) in her son. Case presentation: The mother, a 67-year-old woman, referred to us for a three year-history of mood disturbance and gait impairment, and a more recent hypophonia, dysarthria, dysphagia, and diffuse muscle wasting. Family history was positive for psychiatric disorders and gait disturbances. Brain 18F-FDG PET showed severe hypometabolism in the fronto-temporal brain cortex bilaterally. Electrodiagnostic studies (EDX) showed severe motor axonopathy in the bulbar, cervical and lumbosacral districts. Her 41-year-old son had a history of mood depression and sensory disturbances in the limbs, along with mild muscle wasting, weakness, and reduced reflexes. Nerve conduction studies revealed a moderate sensory-motor polyneuropathy, while brain MRI was normal. Whole exome sequencing of the patients' DNA identified the novel MFN2 (NM_014874.4) variant c.581A>C p.(Asp194Ala). Conclusion: Our findings provide evidence of heterogenous clinical manifestations in family members sharing the same MFN2 molecular defect. Additionally, we present the first documented case of ASL-FTD associated with an MFN2 mutation, thereby expanding the range of MFN-related disorders. Further research involving larger cohorts of patients will be needed to better understand the role of MFN2 as a contributing gene in the development of ALS-FTD.

Peak width of skeletonized mean diffusivity (PSMD) as marker of widespread white matter tissue damage in multiple sclerosis

BACKGROUND

Peak width of skeletonized mean diffusivity (PSMD) is a novel and fully automated, MRI biomarker, which has shown clinical relevance in cerebral small vessel diseases (SVD). We aimed here to assess PSMD levels across the brain of patients with multiple sclerosis (MS), in comparison to normal controls (NC) and patients with CADASIL, a genetically defined form of severe SVD.

METHODS

We assessed PSMD in relapsing-remitting (RR) MS patients (n = 47) in comparison to age-matched CADASIL patients (n = 25) and NC (n = 28). Diffusion Tensor Imaging data were acquired on 1.5T MR clinical scanner to automatically compute PSMD through "skeletonization" of WM tracts and diffusion histograms.

RESULTS

RRMS had lower WM lesion volume (LV) than CADASIL (8.6 ± 8.2 vs 24.4 ± 17.4 cm³, p < 0.001). After correction for LV, PSMD values in MS were higher than in CADASIL patients (adjusted mean values: 4.5 vs 3.9 × 10^-4 mm²/s, p = 0.03) and in both patient groups were higher than in NC (2.8 ± 0.3 × 10^-4 mm²/s, p < 0.001). PSMD values correlated with LV in both patient groups (r = 0.8, p < 0.001 in MS; r = 0.6, p = 0.002 in CADASIL).

CONCLUSIONS

In both patient groups, PSMD was higher than in NC and closely correlated with LV, suggesting sensitivity in assessing brain tissue damage in these disorders. In MS patients, PSMD levels were higher than in CADASIL patients, despite the lower LV. This might be related to more severe normal-appearing WM abnormalities occurring in the MS brains. This novel, fully automated, MRI metric may represent a useful marker for a robust quantification of the diffuse WM tissue damage in MS.

Factor IX Gene Analysis In 70 Unrelated Patients with Haemophilia B: Description of 13 New Mutations

Seventy unrelated patients suffering from haemophilia B have been screened for determining the molecular defect and for evaluating the spectrum of factor IX mutations in the Rhône Alpes region in France. Most patients were characterized with respect to factor IX antigen and factor IX coagulant activity. We have used denaturing gradient gel electrophoresis to obtain a full scanning of the whole coding, promoter, and exon flanking sequences of the factor IX gene. This technique enabled us to determine the molecular defect in 68 out of 70 families (97%), and the mutation was further identified in the two last patients with a direct sequencing of the gene. A total of 2 complete gene deletions in patients with antifactor IX inhibitor, 6 small insertions/ deletions and 62 point mutations were found. Two of these nucleotide substitutions (Arg145His and Ala233Thr) were detected in 21 patients (30%) suggesting the existence of a local founder effect. Thirteen mutations were previously undescribed, including 7 missense mutations. The detection of mutations in patients affected with haemophilia B may shed some light in the structure-function relationship of factor IX molecule within the coagulation system.

Molecular cytogenetic characterization of five F8 complex rearrangements: utility for haemophilia A genetic counselling

BACKGROUND

Genomic inversions are usually balanced, but unusual patterns have been described in haemophilia A (HA) patients for intron 22 (Inv22) and intron 1 (Inv1) inversions leading to the hypothesis of more complex rearrangements involving deletions or duplications.

AIM

To characterize five abnormal patterns either in Southern blot and long-range PCR for Inv22 or in PCR for Inv1.

MATERIALS AND METHODS

All patients were studied using cytogenetic microarray analysis (CMA).

RESULTS

In all cases, CMA analysis found that each inversion was associated with complex Xq28 rearrangement. In three patients, CMA analysis showed large duplication ranging from 230 to 1302 kb and encompassing a various number of contiguous genes among which RAB39B. RAB39B duplication is a strong candidate gene for X-linked intellectual disability (XLID). Surprisingly, none of the severe HA patients with RAB39B duplication reported in this study or in the literature exhibited XLID. We hypothesise that F8 complex rearrangement down regulated RAB39B expression. In the two remaining patients, CMA analysis found Xq28 large deletion (from 285 to 522 kb). Moyamoya syndrome was strongly suspected in one of them who carried BRCC3 deletion.

CONCLUSION

Because several F8 neighbouring genes are associated with other pathologies such as XLID and cardiovascular disease, all HA patients where complex Xq28 rearrangement was suspected should be referred to a geneticist for possible utility of a pangenomic study. Such investigation should be carefully considered in genetic counselling in female carriers to assess the risk of transmitting severe HA with a "contiguous gene syndrome".

Study of six patients with complete F9 deletion characterized by cytogenetic microarray: role of the SOX3 gene in intellectual disability

Essentials Some hemophilia B (HB) patients with complete F9 deletion present with intellectual disability (ID). We delineate six F9 complete deletions and investigate genotype/phenotype correlation. We identify SOX3 as a candidate gene for ID, acting through haploinsufficiency, in HB patients. All complete F9 deletions in ID patients should be explored with cytogenetic microarrays.

SUMMARY

Background Large deletions encompassing both the complete F9 gene and contiguous genes have been detected in patients with severe hemophilia B (HB). Some of these patients present other clinical features, such as intellectual disability (ID). Objectives/Methods In this study, we characterized six unrelated large deletions encompassing F9, by cytogenetic microarray analysis (CMA), to investigate genotype/phenotype correlation. Results Five of the six patients included in this study presented with ID associated with HB. CMA showed that the six large deletions, ranging in size from approximately 933 kb to 9.19 Mb, were located within the Xq26.3 to Xq28 bands. In all cases, the complete deletion of F9 was associated with the loss of various neighboring genes (5-28 other genes). The smallest region of overlap for ID was a 1.26-Mb region encompassing seven OMIM genes (LOC389895, SOX3, LINC00632, CDR1, SPANXF1, LDOC1, SPANXC). SOX3, our candidate gene for ID, encodes an early transcription factor involved in pituitary development. All of the patients studied who had both HB and ID had deletion of the SOX3 gene. Conclusions All HB patients with an atypical phenotype, especially if complete deletion of F9 is suspected, should be referred to a geneticist for possible pangenomic assessment, because haploinsufficiency of genes flanking F9, such as SOX3 in particular, may result in a broader phenotype, including ID. Such assessment would be of particular value for the genetic counseling of female carriers with F9 deletions, as it would facilitate analysis of the risk of transmitting HB associated with ID.

[Identification of knowledge deficits of pharmacy students at the beginning of the fifth year of pharmacy practice experience: Proposals to change the content of academic programs]

INTRODUCTION

In France, community pharmacy students performed a hospital pharmacy practice experience during the 5th year of the university curriculum. The purpose of a part of the content of the academic teaching program delivered before this practice experience is to prepare the students for their future hospital activities. It should enable them for the practical use of knowledge in order to improve pharmacotherapy, laboratory diagnosis and monitoring of patients' care. The aim of this study was to show if there are gaps in this program.

METHODS

Fourteen students performing their clerkship in a teaching hospital were invited to highlight these gaps when they were gradually immersed in the pharmaceutical care. They did so under the careful observation of hospital pharmacist preceptors. These practitioners referred to professional guidelines, documentary tools used in daily clinical practice and publications supporting their pharmaceutical care practices.

RESULTS

Shortcomings and gaps identified were: how to communicate with other healthcare professionals and the content of verbal exchanges, how to conduct a patient-centered consultation, documentation tools required for relevant pharmacist' interventions, codification of pharmacist's interventions, risks related to drug packaging and benefit risk assessment of health information technologies.

DISCUSSION

These gaps represent a handicap by delaying the process that led to move from student to healthcare professional. Hospital pharmacist preceptors have to fill in these gaps before engaging students in pharmaceutical care.

CONCLUSION

These results invite to revise partly the content of the academic teaching program delivered before the 5th year hospital pharmacy practice experience.

[Student assessment of pharmacy practice experiences in France: a national survey]

Pharmacy practice experience (PPE) aims to help trainees to become independent professional practitioners and is a prerequisite for developing skills and competence. In France, it does not exist any study that describes student satisfaction related to preregistration trainings. The aim of this study was to assess student perceptions related to the four PPE types that are planned along the course of study. A questionnaire was sent to each student. Concerning the first and second year introductory PPE, among the 8491 responses, 73% of the students stated that the length was too long regarding their actual knowledge and the objectives were not always achieved. Four thousand and eleven responses regarding third and fourth year PPE were analyzed. Sixty-two percent of the students did not deliver drugs related to the practice's subject and 57% declared doing similar task assigned during the first year PPE especially storage one's. One thousand six hundred and seven questionnaires regarding hospital practices were received. Forty-one percent of the trainees were not asked to perform task that were related to their actual knowledge. Additional comments focused on overmuch shadowing. Among the 853 responses related to the 6th year PPE, 88% of the students considered that they were overall satisfied of the training. Although 30% felt they acquired insufficient skills and professionalism and declared they were not ready to integrate the work world. Those results should prompt decision makers to modify in depth PPE programs in France in order to improve trainees' professionalism and skills acquisition. Promoting and developing researches in the field of PPE is urgently needed.

Identification of new and known polymorphisms in glycoprotein IIb and IIIa genes by denaturing gradient gel electrophoresis

Glycoprotein IIb and IIIa contain antigenic determinants involved in the potential production of allo- or autoantibodies directed against platelets, that may result in severe thrombocytopenia. Most of these epitopes appear to be supported by single nucleotide substitutions. We have used denaturing gradient gel electrophoresis (DGGE) to identify sequence variations within the promoter and the coding regions of the glycoprotein IIb and glycoprotein IIIa genes. Using genomic DNA from 60 unrelated normal individuals, we have amplified short domains that encompass the coding sequences and the exon-intron boundaries of both genes that were further separated according to their melting behaviour during the denaturant electrophoretic migration. Only the fragments with an abnormal migration pattern were sequenced. We confirmed the sensitivity of this method by recognizing both previously described Human Platelet Antigen polymorphisms and mutations affecting either the glycoprotein IIb or the glycoprotein IIIa genes in thrombasthenic patients. We also identified four other polymorphisms. Two were located in the glycoprotein IIb gene, involving intron 21 (C<-->G at nucleotide 10480) and first codon of exon 30 (codon GTC<-->GTT coding for residue Val 990), and two in the glycoprotein IIIa gene (exon 6 CCC<-->CCT coding for residue Pro 268; intron 14 C<--> T at position 37126). The screening of the GPIIIa promoter also revealed three different polymorphisms located at position-468 (A/T polymorphism), -425 (A/C polymorphism) and-400 (A/C polymorphism), which could influence the expression of the complex at the cell surface. Denaturing gradient gel electrophoresis appears to be a sensitive and specific technique for identifying polymorphisms and mutations in the GPIIb and GPIIIa genes.

Synthesis of GPIb beta with novel transmembrane and cytoplasmic sequences in a Bernard-Soulier patient resulting in GPIb-defective signaling in CHO cells

The molecular defect of a new Bernard-Soulier patient, originating from Morocco and presenting thrombocytopenia with large platelets and an absence of ristocetin-induced platelet agglutination, has been identified and reproduced in transfected heterologous cells. Gene sequencing revealed insertion of a guanine in the domain coding for the transmembrane region of the glycoprotein (GP) Ib beta subunit. This mutation causes a translational frame shift, which creates putative novel transmembrane and cytoplasmic 37 and 125 amino acids domains, respectively. A 34 kDa immunoreactive GPIb beta band, instead of the normal 26 kDa subunit, was detected by Western blotting in lysates from the patient's platelets and from transfected cells and in immunoprecipitates of metabolically labeled cells. The abnormal subunit did not associate with GPIb alpha and was mainly intracellular, although a significant fraction could reach the cell surface. Cells expressing the mutant GPIb-IX complex adhered to a von Willebrand factor matrix but were unable to change shape, unlike cells expressing the wild-type receptor. These results strongly suggest a novel role of the GPIb beta subunit and its transmembrane-intracellular region in GPIb-VWF-dependent signaling, in addition to a role in correct assembly and cell surface targeting of the GPIb-V-IX complex.

Two novel mutations in EGF-like domains of human factor IX dramatically impair intracellular processing and secretion

We investigated the mechanisms responsible for severe factor IX (FIX) deficiency in two cross-reacting material (CRM)-negative hemophilia B patients with a mutation in the first and second epidermal growth factor (EGF) domains of FIX (C71Y and C109Y, respectively). We have determined the kinetics of mutant FIX biosynthesis and secretion in comparison with wild-type FIX (FIXwt). In transfected cells, FIXwt was retrieved as two intracellular molecular forms, rapidly secreted into the culture medium. One appeared to be correctly N-glycosylated, and corresponded to a form trafficking between the endoplasmic reticulum (ER) and Golgi apparatus. The other corresponded to the mature form, ready to be secreted, exhibiting correct N-glycosylation and sialylation. In contrast, the two mutants, FIXC71Y and FIXC109Y, were not secreted from the cells and did not accumulate intracellularly. Relative to FIXwt, they were retained longer in the ER and were only N-glycosylated. In addition, the intracellular concentration of the FIX mutants increased when ALLN, an inhibitor of cysteine proteases and of the proteasome degradation pathway, was added to the culture medium. Both the FIX mutants and FIXwt were associated in the ER with the 78-kDa glucose-regulated protein (GRP78/BiP) and calreticulin (CRT), though the amount of CRT associated with the two mutants was twice as strong as with FIXwt. These results strongly suggest that chaperone and lectin molecules act in concert to ensure both proper folding of FIXwt and the retention of mutant molecules.

Description of 10 new mutations in platelet glycoprotein IIb (alphaIIb) and glycoprotein IIIa (beta3) genes

In this study we have used denaturing gradient gel electrophoresis (DGGE) for identifying sequence alterations in glycoprotein (GP) IIb and IIIa genes from 20 patients affected by Glanzmann's thrombasthenia. These patients were from 16 different families. Using computer modelling, we divided the promoters, coding sequences and flanking splicing regions, in 31 segments for the GPIIb gene and 19 domains for the GPIIIa gene. We were able to find a mutation potentially affecting GPIIb-IIIa expression or function in 16 patients out of 20. In six patients from three families, the gypsy mutation modifying the splice donor site of intron 15 of the GPIIb gene was detected. In the other patients, 10 novel mutations were characterised, which were located either in the GPIIb gene (nine cases) or in the GPIIIa gene (one case). The type of mutation was nonsense mutation (one case), missense mutation (five cases), small insertion of 1 bp (one case) and splicing modifications (three cases). Among these genetic events, three were directly responsible for Glanzmann's thrombasthenia, four were localised in regions known to be involved in GPIIb-IIIa complex expression and three mutations were potentially responsible for Glanzmann's thrombasthenia.

[Postoperative combined medullary sclerosis revealing Biermer's disease: toxic effect of nitrous oxide]

Combined medullary sclerosis developed suddenly postoperatively in a patient with unknown Biermer's disease. The neurological lesions were undoubtedly induced by nitrogen protoxide via an inactivation of vitamin B12.

Factor IX gene analysis in 70 unrelated patients with haemophilia B: description of 13 new mutations

Seventy unrelated patients suffering from haemophilia B have been screened for determining the molecular defect and for evaluating the spectrum of factor IX mutations in the Rhône Alpes region in France. Most patients were characterized with respect to factor IX antigen and factor IX coagulant activity. We have used denaturing gradient gel electrophoresis to obtain a full scanning of the whole coding, promoter, and exon flanking sequences of the factor IX gene. This technique enabled us to determine the molecular defect in 68 out of 70 families (97%), and the mutation was further identified in the two last patients with a direct sequencing of the gene. A total of 2 complete gene deletions in patients with antifactor IX inhibitor, 6 small insertions/deletions and 62 point mutations were found. Two of these nucleotide substitutions (Arg145His and Ala233Thr) were detected in 21 patients (30%) suggesting the existence of a local founder effect. Thirteen mutations were previously undescribed, including 7 missense mutations. The detection of mutations in patients affected with haemophilia B may shed some light in the structure-function relationship of factor IX molecule within the coagulation system.

ERGIC-53 gene structure and mutation analysis in 19 combined factors V and VIII deficiency families

Combined factors V and VIII deficiency is an autosomal recessive bleeding disorder associated with plasma levels of coagulation factors V and VIII approximately 5% to 30% of normal. The disease gene was recently identified as the endoplasmic reticulum-Golgi intermediate compartment protein ERGIC-53 by positional cloning, with the detection of two founder mutations in 10 Jewish families. To identify mutations in additional families, the structure of the ERGIC-53 gene was determined by genomic polymerase chain reaction (PCR) and sequence analysis of bacterial artificial chromosome clones containing the ERGIC-53 gene. Nineteen additional families were analyzed by direct sequence analysis of the entire coding region and the intron/exon junctions. Seven novel mutations were identified in 10 families, with one additional family found to harbor one of the two previously described mutations. All of the identified mutations would be predicted to result in complete absence of functional ERGIC-53 protein. In 8 of 19 families, no mutation was identified. Genotyping data indicate that at least two of these families are not linked to the ERGIC-53 locus. Taken together, these results suggest that a significant subset of combined factors V and VIII deficiency is due to mutation in one or more additional genes.

Illegitimate transcription: its use for studying genetic abnormalities in lymphoblastoid cells from patients with Glanzmann thrombasthenia

Glanzmann thrombasthenia is the most common inherited disorder of platelets that may induce severe bleeding complications. Molecular biology techniques have offered the possibility to assess the basis of this chronic haemorrhagic disease at the molecular level. However, the accessibility of mRNA in platelets is limited by the availability of the patient's blood samples and the relatively weak amount of this material in these cells. Taking advantage of the genetic phenomenon of illegitimate transcription, we have demonstrated that glycoprotein IIb and glycoprotein IIIa mRNA could be detected in lymphoblastoid cell lines issued from normal EBV-transformed lymphoblasts. We further analysed the sequences of the two glycoprotein transcripts in lymphoblastoid cell lines from two previously characterized patients presenting with Glanzmann thrombasthenia. The results showed that illegitimate transcripts presented similar molecular abnormalities to those found in platelets. These data demonstrated that the nucleotide sequences of illegitimate transcripts were identical to tissue-specific mRNA found in platelets. We applied this methodology to screen for the genetic defect in a new thrombasthenic patient, and found a homozygous nonsense mutation GCA-->TGA converting Arg8 to stop in the glycoprotein IIIa gene. This immortalized source of genetic material is therefore particularly useful for molecular genetic studies in inherited platelet disorders, avoiding repetitive and large blood samplings in frequently anaemic patients.

Thromboangiitis obliterans with inaugural rheumatic manifestations. A report of three cases

Thromboangiitis obliterans, or Buerger's disease, is a segmental occlusive inflammatory disorder of the small- and medium-sized arteries and veins seen in young adults and associated with cigarette smoking. The lesions are most marked in the distal limbs. We report three cases in which the first manifestations were rheumatic, consisting in polyarthritis in two cases and carpal tunnel syndrome in one. Rheumatic manifestations are infrequent and rarely inaugural in thromboangiitis obliterans, although they are probably underdiagnosed. Their pathogenesis is unclear but may involve autoimmunity. Heightened awareness of the possibility that rheumatic manifestations can inaugurate thromboangiitis obliterans may allow an earlier diagnosis of this disease, which may improve the functional prognosis. However, recovery can be achieved only if the patient stops smoking.

A nonsense mutation in the GPIIb heavy chain (Ser 870-->stop) impairs platelet GPIIb-IIIa expression

Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder, caused by a quantitative or qualitative defect of the GPIIb-IIIa integrin (alpha IIb beta 3), which functions as the platelet fibrinogen receptor. We report a case of type I GT due to a homozygous mutation resulting in Ser 870 to stop codon substitution. This residue is located near the proteolytic cleavage site of proGPIIb. The mutation results in a GPIIb truncated of 138 amino acids, including transmembrane and intracytoplasmic domains. Cotransfection of an expression vector containing the mutant GPIIb and wild-type GPIIIa showed that the mutant Ser 870-->stop GPIIb was able to associate to GPIIIa. However, this heterodimer failed to mature as shown by endoglycosidase-H digestion and was therefore not expressed at the COS-7 cell surface. This report is the first description of a homozygous nonsense mutation in the GPIIb gene and highlights the role of the GPIIb light chain.

Combined hereditary disorders of haemophilia B Leyden (-6 G-->A) and type 1 von Willebrand disease

Multiple coagulation disorders are unusual. We report here a combination of haemophilia B Leyden with type 1 von Willebrand disease (vWD) affecting different members of the same family. Haemophilia B Leyden was due to a -6 G-->A mutation within the promoter of the factor IX gene and was responsible for a mild haemophilia in the father of the proband. The proband and her sister (age 4 and 6) exhibited a twofold lower level of factor IX activity (0.4 IU/ml) than the paternal grandmother (0.95 IU/ml). The differences in F IX levels in the three carriers of the same -6 G-->A mutation suggest the implication of an age-related mechanism responsible for the increase in factor IX plasma level. Haemophilia B Leyden patient and carriers suffered also from a mild von Willebrand disease. The diagnosis of this associated type 1 vWD was performed by assaying plasma von Willebrand factor together with multimer electrophoretic studies and DDAVP test. The inheritance of this vWD was investigated by haplotype analysis of the vWF gene. Individuals affected by such an association are actually asymptomatic, but per- and post-operative bleeding risk remains to be evaluated.

Interference of heparin in plasma levocarnitine determination with radioenzyme assay

This paper describes the interference of heparin (CAS 9005-49-6) in whole plasma used for free and total levocarnitine (L-carnitine, CAS 541-15-1) analysis. Alkaline hydrolysis required for total L-carnitine measurement does not overcome the problem. The same interference is also present in long-chain acyl-L-carnitine assay, because heparin precipitates together with proteins and long-chain esters of L-carnitine in the acid insoluble fraction of perchloric acid treated plasma sample. In this case an appropriate cleaning of the sample is recommended before the assay.

Predictors of the need for total hip replacement in patients with osteoarthritis of the hip

RATIONALE

the natural history and risk factors for hip osteoarthritis are still unknown.

OBJECTIVE

to identify factors predicting a need for total hip replacement at some time during the course of hip osteoarthritis.

PATIENTS AND METHODS

outpatients evaluated between 1981 and 1986 for hip osteoarthritis were studied retrospectively. The date of diagnosis and the characteristics of the patients and hip disease at diagnosis were recorded. The risk of eventual total hip replacement was estimated using the Kaplan-Meier method. Uni- and multivariate Cox proportional hazard models were used to determine the value of each variable for predicting total hip replacement.

RESULTS

we included 149 patients (50 males). The risk of total hip replacement was estimated at 36 +/- 4% five years after diagnosis. Factors with significant effects in the multivariate analysis were age older than 54 years at diagnosis (relative risk 3.15), body mass index greater than 27 (relative risk 2.97), and severe radiological joint space narrowing at diagnosis (relative risk 2.26).

CONCLUSION

this study confirmed the often severe course of hip osteoarthritis and identified several factors possibly associated with rapid progression.

Factor VIII gene inversions in severe hemophilia A: results of an international consortium study

Twenty-two molecular diagnostic laboratories from 14 countries participated in a consortium study to estimate the impact of Factor VIII gene inversions in severe hemophilia A. A total of 2,093 patients with severe hemophilia A were studied; of those, 740 (35%) had a type 1 (distal) factor VIII inversion, and 140 (7%) showed a type 2 (proximal) inversion. In 25 cases, the molecular analysis showed additional abnormal or polymorphic patterns. Ninety-eight percent of 532 mothers of patients with inversions were carriers of the abnormal factor VIII gene; when only mothers of nonfamilial cases were studied, 9 de novo inversions in maternal germ cells were observed among 225 cases (approximately 1 de novo maternal origin of the inversion in 25 mothers of sporadic cases). When the maternal grandparental origin was examined, the inversions occurred de novo in male germ cells in 69 cases and female germ cells in 1 case. The presence of factor VIII inversions is not a major predisposing factor for the development of factor VIII inhibitors; however, slightly more patients with severe hemophilia A and factor VIII inversions develop inhibitors (130 of 642 [20%]) than patients with severe hemophilia A without inversions (131 of 821 [16%]).

Molecular study of Glanzmann thrombasthenia in 3 patients issued from 2 different families

In an effort to further understand Glanzmann thrombasthenia (GT) 3 patients from 2 different families were studied. After biochemical and immunological analysis these patients were classified as type I. We observed in the first family a new restriction site for Stu I in exon II of the glycoprotein (GP) IIIa gene caused by a homozygous nonsense mutation: 62 Arg to stop codon. The parents were heterozygotes for this mutation. We found in the second family a previously described nonsense mutation: 584 Arg to stop codon in exon 17 of the GPIIb gene. The father and his two affected sons were heterozygous for this genetic defect. This mutation 62 Arg to stop codon is a new description of a genetic defect associated with GT. Furthermore, the discovery of the same mutation in 3 affected families from different ethnic groups raises the possibility of either a hot spot mutation in the CG dinucleotide region of GPIIb gene, or an ancient mutant allele present in diffuse populations at a relatively high frequency.

Combined factor IX and protein C deficiency in a child: thrombogenic effects of two factor IX concentrates

We have recently described an unusual situation which involved a combination of a factor IX and a protein C deficiency in a young child who presented, according to the bleeding tendency, as a hemophilia B patient. In this particular hemophiliac, baseline prothrombin fragment F1 + 2 levels were unexpectedly elevated and increased after an injection of a very high purity factor IX concentrate. This observation raised a question regarding the substitution schedule in the case of repeated injections of factor IX, since the thrombotic tendency has been a major concern with some factor IX concentrates. We monitored factor IX, prothrombin fragment F1 + 2, and D-dimer plasma levels before and during the 6 hr following the injection of an immunopurified factor IX concentrate. The results showed an increase in the F1 + 2 levels after the factor IX injection, but an increase lower than previously observed with an ion-exchange chromatography-purified concentrate. Furthermore, the F1 + 2 level returned to baseline value 6 hr after administration. This factor IX concentrate seems to be best for use in the patient where repeated injections are involved (as employed during surgery). Moreover, the data point out the advantage of a monoclonal antibody-purified factor IX concentrate over less purified concentrates in a specific situation, with regard to the thrombogenic risk.

Urine pentamidine as an indicator of lung pentamidine in patients receiving aerosol therapy

To determine if urine pentamidine was reflective of lung pentamidine, we compared levels of the drug in bronchoalveolar lavage fluid and simultaneously obtained urine. Thirty-one patients who were receiving aerosolized pentamidine either as treatment or as prophylaxis underwent BAL and submitted urine samples for pentamidine analysis. Pentamidine was analyzed in both phases of BAL fluid (supernatant and cell pellet) and in urine using high performance liquid chromatography. Urine results were normalized for creatinine. Patients were categorized as prophylaxis failures (active Pneumocystis carinii pneumonia on prophylaxis), electives (free from PCP on prophylaxis), treatment (daily AP in treatment doses for active PCP, or miscellaneous (single dose of AP). Levels in BAL fluid and urine varied widely over several orders of magnitude. However, for all patients, we found a highly significant relationship between BAL supernatant and urine (r = 0.97, p less than 0.0001). No statistical differences were found when comparing levels of pentamidine between failures and electives; however, the number of failures was small. We conclude that urine pentamidine is related to lung pentamidine and can be used as a clinical indicator in patients receiving aerosolized therapy.