Germline mutations of the CBL gene define a new genetic syndrome with predisposition to juvenile myelomonocytic leukaemia

BACKGROUND

CBL missense mutations have recently been associated with juvenile myelomonocytic leukaemia (JMML), an aggressive myeloproliferative and myelodysplastic neoplasm of early childhood characterised by excessive macrophage/monocyte proliferation. CBL, an E3 ubiquitin ligase and a multi-adaptor protein, controls proliferative signalling networks by downregulating the growth factor receptor signalling cascades in various cell types.

METHODS AND RESULTS

CBL mutations were screened in 65 patients with JMML. A homozygous mutation of CBL was found in leukaemic cells of 4/65 (6%) patients. In all cases, copy neutral loss of heterozygosity of the 11q23 chromosomal region, encompassing the CBL locus, was demonstrated. Three of these four patients displayed additional features suggestive of an underlying developmental condition. A heterozygous germline CBL p.Y371H substitution was found in each of them and was inherited from the father in one patient. The germline mutation represents the first hit, with somatic loss of heterozygosity being the second hit positively selected in JMML cells. The three patients display a variable combination of dysmorphic features, hyperpigmented skin lesions and microcephaly that enable a 'CBL syndrome' to be tentatively delineated. Learning difficulties and postnatal growth retardation may be part of the phenotype.

CONCLUSION

A report of germline mutations of CBL in three patients with JMML is presented here, confirming the existence of an unreported inheritable condition associated with a predisposition to JMML.

Pseudoexon exclusion by antisense therapy in methylmalonic aciduria (MMAuria)

Development of pseudoexon exclusion therapies by antisense modification of pre-mRNA splicing represents a type of personalized genetic medicine. Here we present the cellular antisense therapy and the cell-based splicing assays to investigate the effect of two novel deep intronic changes c.1957-898A>G and c.1957-920C>A identified in the methylmalonyl-coenzyme A (CoA) mutase (MUT) gene. The results show that the nucleotide change c.1957-898A>G is a pathological mutation activating pseudoexon insertion and that antisense morpholino oligonucleotide (AMO) treatment in patient fibroblasts leads to recovery of MUT activity to levels 25 to 100% of control range. On the contrary, the change c.1957-920C>A, identified in two fibroblasts cell lines in cis with c.1885A>G (p.R629G) or c.458T>A (p.D153V), appears to be a rare variant of uncertain clinical significance. The functional analysis of c.1885A>G and c.458T>A indicate that they are the disease-causing mutations in these two patients. The results presented here highlight the necessity of scanning the described intronic region for mutations in MUT-affected patients, followed by functional analyses to demonstrate the pathogenicity of the identified changes, and extend previous work of the applicability of the antisense approach in methylmalonic aciduria (MMAuria) for a novel intronic mutation.

Unilateral taxane-induced onychopathy in a patient with a brain metastasis

Chemotherapy using taxanes have been useful in the treatment of several types of solid tumors. Nail abnormalities have been reported primarily with the use of docetaxel, but also with low dose, weekly paclitaxel. We report a patient with 20-nail onycolysis associated with the use of paclitaxel that resolved after stopping the medication and then recurred after the use of docetaxel, but spared all the nails of a paretic hand.

[Heptavalent-pneumococcal conjugate vaccine (Prevenar). Differences in effectiveness between populations]

This article reviews the publications on the effectiveness of heptavalent-pneumococcal conjugate vaccine (PCV7) in the prevention of invasive pneumococcal disease (IPD) in children under five years of age. It also analyses the characteristics of the vaccine and its impact on the epidemiology of IPD in different places. Before the introduction of PCV7, the percentage of cases of IPD due to vaccine serogroups oscillated between 89% in the United States and 43% in Asia. In Spain it was 68%. Active laboratory-based surveillance shows that the introduction of PCV7 has had a highly variable impact on the incidence of IPD, with falls oscillating between 91% in the United States and 12% in Navarre, Spain. The global effectiveness of VNC7v in published studies varies between 31% and 89%, chiefly depending on the patterns of pneumococcal serotypes in each place. Numerous studies show a variable replacement capacity of the pneumococci, which means the effect of the vaccine can be reduced, as non-vaccine serotypes occupy the space left by the vaccine ones. A study in Navarre has found a risk of IPD due to non-vaccine serotypes that is 6 times higher in vaccinated children than in unvaccinated ones. In places where less than 70% of the serotypes that cause IPD are represented in the VNC7v, the effectiveness of its introduction in the vaccination will probably be slight and the routine vaccination schedule serotypes fast. In these cases, VNC7v could be reserved for children with IPD risk factors.

Methylmalonic acidaemia: examination of genotype and biochemical data in 32 patients belonging to mut, cblA or cblB complementation group

Methylmalonic acidaemia (MMA) is a genetic disorder caused by defects in methylmalonyl-CoA mutase or in any of the different proteins involved in the synthesis of adenosylcobalamin. The aim of this work was to examine the biochemical and clinical phenotype of 32 MMA patients according to their genotype, and to study the mutant mRNA stability by real-time PCR analysis. Using cellular and biochemical methods, we classified our patient cohort as having the MMA forms mut (n = 19), cblA (n = 9) and cblB (n = 4). All the mut (0) and some of the cblB patients had the most severe clinical and biochemical manifestations, displaying non-inducible propionate incorporation in the presence of hydroxocobalamin (OHCbl) in vitro and high plasma odd-numbered long-chain fatty acid (OLCFA) concentrations under dietary therapy. In contrast, mut (-) and cblA patients exhibited a milder phenotype with propionate incorporation enhanced by OHCbl and normal OLCFA levels under dietary therapy. No missense mutations identified in the MUT gene, including mut (0) and mut (-) changes, affected mRNA stability. A new sequence variation (c.562G>C) in the MMAA gene was identified. Most of the cblA patients carried premature termination codons (PTC) in both alleles. Interestingly, the transcripts containing the PTC mutations were insensitive to nonsense-mediated decay (NMD).

Propionic and methylmalonic acidemia: antisense therapeutics for intronic variations causing aberrantly spliced messenger RNA

We describe the use of antisense morpholino oligonucleotides (AMOs) to restore normal splicing caused by intronic molecular defects identified in methylmalonic acidemia (MMA) and propionic acidemia (PA). The three new point mutations described in deep intronic regions increase the splicing scores of pseudoexons or generate consensus binding motifs for splicing factors, such as SRp40, which favor the intronic inclusions in MUT (r.1957ins76), PCCA (r.1284ins84), or PCCB (r.654ins72) messenger RNAs (mRNAs). Experimental confirmation that these changes are pathogenic and cause the activation of the pseudoexons was obtained by use of minigenes. AMOs were targeted to the 5? or 3? cryptic splice sites to block access of the splicing machinery to the pseudoexonic regions in the pre-mRNA. Using this antisense therapeutics, we have obtained correctly spliced mRNA that was effectively translated, and propionyl coenzyme A (CoA) carboxylase (PCC) or methylmalonylCoA mutase (MCM) activities were rescued in patients' fibroblasts. The effect of AMOs was sequence and dose dependent. In the affected patient with MUT mutation, close to 100% of MCM activity, measured by incorporation of (14)C-propionate, was obtained after 48 h, and correctly spliced MUT mRNA was still detected 15 d after treatment. In the PCCA-mutated and PCCB-mutated cell lines, 100% of PCC activity was measured after 72 h of AMO delivery, and the presence of biotinylated PCCA protein was detected by western blot in treated PCCA-deficient cells. Our results demonstrate that the aberrant inclusions of the intronic sequences are disease-causing mutations in these patients. These findings provide a new therapeutic strategy in these genetic disorders, potentially applicable to a large number of cases with deep intronic changes that, at the moment, remain undetected by standard mutation-detection techniques.

The tetrahydrobiopterin loading test in 36 patients with hyperphenylalaninaemia: evaluation of response and subsequent treatment

The response to tetrahydrobiopterin (BH4) in patients with phenylalanine hydroxylase (PAH, EC 1.14.16.1) deficiency (OMIM 261600) has been widely reported. Here we report results of the BH4 loading test (20 mg/kg per day) in a group of 36 patients with PAH deficiency and phenotype of mild hyperphenylalaninaemia (HPA), mild phenylketonuria (PKU) or classic PKU. The patients ranged from neonates aged 7-15 days, detected in the Newborn Screening Programme for PKU in the population of Galicia (NW Spain), to adults aged up to 32 years who had been receiving a low-phenylalanine (Phe) diet for a period of years. Ten of the 36 patients showed a reduction of more than 30% in plasma Phe levels within 24 h of BH4 loading (ranging from 33.7% to 90.2%, mean 59.2%, SD 19.8%). All the patients with mild HPA (100%) showed a positive response; 57% of patients with mild PKU (4 of 7) showed a positive response. Of particular interest were positive responses in two patients with classic PKU, and in one patient with mutations of the phenylalanine hydroxylase (PAH) gene that have not to date been reported to be BH4-responsive (p.S303A and p.G46S). BH4 treatment (5-8 mg/kg per day) was commenced in 9 of the 10 BH4-responsive patients. The observed responses to treatment argue for application of the BH4 loading test in all patients with HPA or PKU, independently of genotype, phenotype or age.

First Spanish series of intestinal transplantation in adult recipients

BACKGROUND

short-bowel transplantation has experienced a substantial growth worldwide following improved results from the late 1990's on, and its coverage by Medicare. According to the International Registry (1985-2005), a total of 1,292 intestinal transplants for 1,210 patients in 65 hospitals across 20 countries have been carried out thus far.

OBJECTIVE

to know short-term (6 months) results regarding patient and graft survival from the first Spanish series of intestinal transplants in adult recipients.

MATERIAL AND METHODS

we present our experience in the assessment of 20 potential candidates to short-bowel transplantation between June 2004 and October 2005. Of these, 10 patients were rejected and 4 were transplanted, which makes up the sample of our study.

RESULTS

to this date 5 transplants have been carried out in 4 patients (2 retransplants, 2 desmoid tumors, 1 short bowel syndrome after excision as a result of mesenteric ischemia). Upon study completion and after a mean follow-up of 180 days (range 90-190 days) all recipients are alive, and all grafts but one (75%) are fully operational, with complete digestive autonomy. All patients received induction with alemtuzumab except one, who received thymoglobulin; in all induction was initiated with no steroids.

CONCLUSIONS

intestinal transplantation represents a therapeutic option that is applicable in our setting and valid for recipients with an indication who have no other feasible alternative to keep their intestinal failure under control.

Comparative analysis of the results of orthotopic liver transplantation in patients with and without portal vein thrombosis

INTRODUCTION

Portal vein thrombosis (PVT), which had been considered an absolute contraindication to orthotopic liver transplantation (OLT), is currently considered a risk factor that increases morbi-mortality. The objective of this study was to compare OLT outcomes in patients with vs without PVT.

MATERIALS AND METHODS

Between April 1986 and December 2003, a sample of 83 patients with PVT was compared with another sample of 83 patients without PVT among 962 OLT performed in our department.

RESULTS

Both groups were homogeneous in terms of epidemiological variables, surgical technique, immunosuppression, and donor-related variables. There were no differences with respect to graft function during the first week following surgery. Surgical time and anhepatic phase duration was longer in the PVT group, albeit the differences were not significant. PVT patients also required more transfusions; a strong statistical association was observed with respect to blood (P = .12) and plasma (P = .11) transfusions and statistically significant differences regarding platelet transfusions (P = .02). Time on mechanical ventilation and the length of stay in the ICU were longer but not significant among PVT patients. The only statistically significant difference was the incidence of portal rethrombosis (P = .02). With respect to mean and global patient and graft actuarial survivals after 1, 3, 5, and 10 years, we have observed no significant intergroup differences, although both patient (P = .48; NS) and graft (P = .96, NS) survivals were lower among PVT cases.

CONCLUSIONS

PVT should not only cease to be considered a contraindication for OLT, but there were no significant differences between the outcomes despite this finding.

Modulation of hepatocyte growth factor plasma levels in relation to the dose of exogenous heparin administered: an experimental study in rats

INTRODUCTION

Partial liver transplantation has been consolidated to be a valid treatment option. We sought to understand the factors that modulate and may be harnessed to accelerate hepatocyte regeneration. We sought to determine the impact of heparin on m-hepatocyte growth factor (HGF) plasma concentrations.

MATERIALS AND METHODS

Sixteen rats were assigned to four groups of four animals each: group A, without heparin; group B, 600 IU/kg; group C, 1000 IU/kg, group D, 1400 IU/kg. Blood samples (0.5 mL) were obtained from each rat at baseline and at 30, 60, 120, and 240 minutes. After the samples were centrifuged to separate supernates from the cell phase they were stored at -20 degrees C in the m-HGF reagent and subsequently tested using enzyme-linked immunosorbent assay. Results were analyzed using SPSS 11.5 statistical software.

RESULTS

Among the 16 rats, one died at 110 minutes, just prior to the last extraction. The remaining rats were sacrificed. Mean weight was: 466 +/- 64.24 g with no intergroup differences (P = .149). The comparative results (using Student t test) were: baseline A(1-4) versus A(1-4) 30 minutes: P < .05; baseline A(1-4) versus A(1-4) 60 minutes: P < .05; baseline A(1-4) versus A(1-4) 120 minutes: P = .10 (NS); baseline A(1-4) versus A(1-4) 240 minutes: P = .15 (NS). No significant differences were found among group B: baseline C(1-4) versus C(1-4) 30 minutes and 60 minutes: NS; baseline C(1-4) versus C(1-4) 120 minutes: P < .001; baseline C(1-4) versus C(1-4) 240 minutes: P < .10 (NS). Finally, the results in group D were: baseline D(1-4) versus D(1-4) 30 minutes: NS; baseline D(1-4) versus D(1-4) 60 minutes and 120 minutes: P < .05; baseline D(1-4) versus D(1-4) 240 minutes: P < .0005. When we compared group A to C and D, we detected differences (albeit not when compared to B) with P values = .01. Peak values were obtained at 120 and 240 minutes (225.21 pg/mL and 221.78 pg/mL) among groups C and D.

CONCLUSION

Heparin has a positive effect to increase serum HGF concentrations among rats. The effect was dependent on the administered dose and the time elapsed.

Incidence and risk factors of development of lung tumors after liver transplantation

INTRODUCTION

Lung tumors have been related to tobacco and alcohol. The incidence increases after orthotopic liver transplantation (OLT) especially when it is performed because of alcoholic cirrhosis.

PATIENTS AND METHODS

We analyzed the incidence and risk factors for de novo lung tumors among 701 patients who underwent OLT between April 1986 and July 2004, after exclusion of pediatric recipients and adults who died within 2 months after OLT.

RESULTS

The incidence of de novo lung tumors was 15 patients (2.1%), including 12 (4.3%) who underwent OLT for alcoholic cirrhosis and 3 (0.7%) for nonalcoholic diseases. There were 14 men and 1 woman of mean age at OLT of 50.8 +/- 9.6 years. Mean time from OLT to lung tumor was 83 +/- 43 months (range, 10-184 months). Thirteen patients (86.6%) were heavy smokers before OLT and 8 (61.5%) continued after OLT; 12 patients (80%) were heavy drinkers before OLT. Ten patients were immunosuppressed with CyA and 5 with tacrolimus. Acute rejection episodes before tumor diagnosis occurred in 6 patients (40%). Two patients underwent thoracotomy, but only one was resected. The remaining 13 patients were unresectable because of locally advanced tumor or metastatic disease. Two unresectable patients received palliative chemotherapy. All patients died with a mean survival from tumor diagnosis, of 5.3 months (range, 3 days to 33 months).

CONCLUSION

A significantly higher incidence of lung tumors was observed among patients who underwent OLT for alcoholic cirrhosis, usually diagnosed in advanced stages of poor prognosis and low survival.

PK and PK/PD of doxycycline in drinking water after therapeutic use in pigs

A commercial doxycycline formulation was administered in drinking water to 12 pigs at the recommended dose of 10 mg/kg daily for 5 days. The mean plasma concentration at steady-state was 1.37 +/- 1.21 microg/mL, which was reached at 68 +/- 27.2 h postadministration. Absorption and elimination half-life values were 7.20 +/- 2.42 and 7.01 +/- 2.10 h, respectively. Most plasma concentrations during dosing were higher than the minimum inhibitory concentrations (MICs) described for the main porcine bacterial pathogens of the respiratory tract (Pasteurella multocida, Actinobacillus pleuropneumoniae, Bordetella bronchiseptica and Mycoplasma hyopneumoniae). It is concluded that when pigs were treated with doxycycline in drinking water at the recommended rate, therapeutically effective concentrations were achieved throughout the treatment period, supporting the clinical use of this tetracycline in the control of respiratory infections. However, inter-animal differences were marked.

Prenatal diagnosis of propionic acidemia

In this report we summarize our experience in prenatal diagnosis of propionic acidemia (PA) since 1987. Overall, we have investigated 25 pregnancies at risk from 19 unrelated families. Until genetic structure of the genes involved in PA was elucidated, prenatal diagnosis has been successfully performed by means of metabolite quantitation and/or enzymatic assays in foetal issue. Today, direct propionyl-CoA carboxylase activity assay in combination with molecular analysis in chorion villi can be regarded as a fast and reliable method of choice for prenatal diagnosis of this organic acidemia.

Sensitive stripping voltammetry of heavy metals by using a composite sensor based on a built-in bismuth precursor

A new graphite-epoxy composite electrode (GECE) containing Bi(NO(3))(3) as a built-in bismuth precursor for simultaneous and individual anodic stripping analysis of heavy trace metals like lead and cadmium is reported. The developed Bi(NO(3))(3)-GECE is compatible with bismuth film electrodes reported previously including the composite electrodes (Bi-GECE) recently reported by our group. Bi(NO(3))(3)-GECE displays the ability for the detection of both individual and simultaneous determination of heavy trace metals and exhibits well defined, reproducible and sharp stripping signals. The sensitive response is combined with the minimal toxicity of Bi(NO(3))(3). This novel sensor would be an appropriate alternative tool to sensors using bismuth in solution during their utilization in environmental quality monitoring as well as other applications.

Propionic acidemia: mutation update and functional and structural effects of the variant alleles

Mutations in the PCCA or PCCB genes, encoding both subunits of propionyl-CoA carboxylase, result in propionic acidemia, a life-threatening inborn error of metabolism with autosomal recessive inheritance. To date, 41 mutations in the PCCA gene and 54 in the PCCB gene have been reported, most of them single base substitutions causing amino acid replacements, and a variety of small insertions and deletions and splicing defects. A greater heterogeneity is observed in the PCCA gene, specially in Caucasians, with no prevalent mutations, while in the Japanese population three mutations account for more than half of the alleles studied. For the PCCB gene a limited number of mutations is responsible for the majority of the alleles characterized in both Caucasian and Oriental populations. These two populations show a different mutational spectrum, only sharing some involving CpG dinucleotides probably as recurrent mutational events. Functional characterization of the mutant missense alleles has been accomplished using different prokaryotic and eukaryotic systems, and the structural consequences have been analyzed in the available crystal models. For the PCCA gene, the main molecular effect of the expressed mutations is related to protein instability, except two mutations in the active site predictably affecting ATP binding. In the PCCB gene the majority of the analyzed mutations are predicted to alter the active site conformation resulting in diminished activity. A few carboxy-terminal PCCB mutations affect the interaction between subunits and the assembly with PCCA to form a functional PCC oligomer. The amount of normal transcripts resulting from some PCCA and PCCB splicing mutations has also been analyzed. Overall, the data generated from the expression analysis reveal potential genotype-phenotype correlations for this clinically heterogeneous disorder.