Perceived neuropsychological impairment inversely related to self-reported health and employment in multiple sclerosis.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) patients frequently report cognitive difficulties which impact daily functioning. The objective was to investigate the relationship between patient-reported cognitive impairment and depression, demographic and MS-related variables, and to clarify its impact on self-reported health measures and employment. METHOD: A large two-centre survey included the MS Neuropsychological Screening Questionnaire (MSNQ), the two-question screening tool for depression, vitality, health-related quality of life, the Health-Promoting Lifestyle Profile II and questions assessing social network satisfaction and employment status. RESULTS: Of the 751 respondents (median age 54 years, median Expanded Disability Status Scale 5, 66.2% female), two-thirds reported perceived neuropsychological impairment or depressive symptoms. Whilst depressive symptoms were related to higher MSNQ scores, the MSNQ poorly predicted depression. After correcting for confounders, higher MSNQ scores and depressive symptoms decreased vitality, health-related quality of life and health-promoting behaviours and increased the probability of being socially dissatisfied. In participants below retirement age, higher MSNQ and Expanded Disability Status Scale scores increased the probability of unemployment, whilst depression did not. CONCLUSION: The contribution of the MSNQ to self-reported health measures and its unique explanatory power regarding unemployment suggest that subjective cognitive complaints are connected to subtle, yet meaningful, neuropsychological dysfunction.

Electronic visual analogue scales for pain, fatigue, anxiety and quality of life in people with multiple sclerosis using smartphone and tablet: a reliability and feasibility study.

OBJECTIVE: To explore the reliability and feasibility of electronic visual analogue scales in people with multiple sclerosis (MS) and healthy individuals. DESIGN: Cross-sectional observational study Setting: Clinical setting Subjects: Convenience sample of 52 people with MS and 52 matched healthy controls Interventions: NA Main measures: Participants scored 15 statements assessing fatigue, pain, anxiety and quality of life on an electronic visual analogue scale (eVAS), either using a smartphone or a tablet (randomly allocated). To check for test-retest reliability, statements were administered in two separate randomly ordered groups. Subjects completed a feasibility questionnaire. RESULTS: Mean (SD) eVAS scores ranged from 35 (28.1) to 80 (22.1) in MS group, and from 57 (28.0) to 86 (13.2) in controls. Intra Class Correlations ranged from 0.73 to 0.95 in MS sample; 0.61 to 0.92 in controls. For most statements, Bland-Altman plots indicated no systematic error, but relatively large random error of the eVAS scores (exceeding 20mm). Considerable ceiling effects (i.e. better health) were found in healthy controls. Similar reliability was found among smartphone or tablet, different demographic groups and the experience-groups. CONCLUSION: Electronic visual analogue scales are reliable and useful for people with MS to register fatigue, pain, anxiety and quality of life.

A 10-year follow-up of the European multicenter trial of interferon ß-1b in secondary-progressive multiple sclerosis.

OBJECTIVES: To explore long-term effects of treatment and prognostic relevance of variables assessed at baseline and during the European secondary progressive multiple sclerosis (SPMS) trial of interferon beta 1b (IFNB-1b). METHODS: We assessed 362 patients (60% female; median age 41 years; Expanded Disability Status Scale (EDSS): 5.5; 51% randomized to IFNB-1b) for their EDSS and treatment history after 10 years. Non-parametric analysis of covariance (ANCOVA) and multivariate linear regression models were applied. RESULTS: Median EDSS was 6.0 at the end of the randomized controlled trial (RCT), in the IFNB-1b and placebo groups, and 7.0 in long-term follow-up patients (those receiving IFNB-1b in the RCT were 6.5 and those receiving placebo in the RCT were 7.0; p = 0.086). 24 patients (6.6%) were deceased. The EDSS at baseline and the EDSS change during the RCT were the most important predictors of the EDSS 10 years later (partial R(2): 0.47). The ability to predict changes in EDSS 10 years after the RCT was limited (R(2): 0.12). Magnetic resonance imaging (MRI) measures remained in the predictive models, but explained < 5% of the variability. CONCLUSIONS: The results from this analysis did not provide convincing evidence to support a favorable long-term outcome in those patients allocated IFNB-1b during the RCT, in our SPMS cohort. The progressive stage of the disease remains largely unpredictable by clinical and conventional MRI measures, so better prognostic markers are needed.

Self-reported levels of education and disability progression in multiple sclerosis.

OBJECTIVES: The purpose of our study is to investigate whether socioeconomic indicators such as education, financial concerns, employment, and living status are associated with disease progression in relapsing-onset and progressive-onset Multiple Sclerosis (MS). MATERIALS AND METHODS: We performed a cross-sectional survey among individuals with MS, registered by the Flemish MS society and included socioeconomic indicators. A Cox proportional hazard regression was performed with the time from MS onset and from birth to reach an ambulatory disability milestone corresponding to Expanded Disability Status Scale (EDSS) 6 (requiring a cane) as outcome measure, adjusted for gender, age at MS onset, and immunomodulatory treatment. RESULTS: Among the participants with relapsing-onset MS, subjects reporting education for more than 12 years had a reduced risk of reaching EDSS 6 compared to subjects reporting education for less than 12 years [HR from onset 0.68 (95% CI 0.49-0.95); HR from birth 0.71 (95% CI 0.51-0.99)]. In progressive-onset MS, longer education was associated with an increased hazard to reach EDSS 6 [HR from onset 1.25 (95% CI 0.91-1.70); HR from birth 1.39 (95% CI 1.02-1.90)]. CONCLUSIONS: Our study shows an association of self-reported levels of education with disability progression in MS, with the highest level being protective in relapsing-onset MS.

The Symbol Digit Modalities Test as sentinel test for cognitive impairment in multiple sclerosis.

BACKGROUND AND PURPOSE: Cognitive impairment (CI) is found in about half of the multiple sclerosis (MS) population and is an important contributor to employment status and social functioning. CI is encountered in all disease stages and correlates only moderately with disease duration or Expanded Disability Status Scale scores. Most present neuropsychological test batteries are time-demanding and expensive. The Symbol Digit Modalities Test (SDMT) has been suggested as a screening tool for CI in MS. In this paper, we aim to assess the performance of the SDMT in predicting the outcome of an extensive battery. METHODS: Neuropsychological test results from 359 patients were assessed in a multidisciplinary MS center (National MS Center Melsbroek, Belgium). Using receiver operating characteristic curves, the performance of the SDMT in predicting the general cognitive outcome of the extensive Neuropsychological Screening Battery for MS (NSBMS) could be assessed. The performance of the SDMT was assessed for different levels of CI and compared with other cognitive tests. Finally, useful covariates were included in a logistic regression model. RESULTS: At a specificity of 0.60 a high sensitivity (0.91) was obtained indicating the potential of the SDMT as a sentinel test for CI in MS. The SDMT outperformed the individual tests included in the NSBMS, used as benchmark. As the logistic regression model did not result in a relevant improvement, it is concluded that most clinical variables influence both the SDMT and the NSBMS in a similar way. Excluding patients with possible practice effects, an optimal cutoff of 40 was found for the SDMT. CONCLUSION: As the SDMT is an easy, low-cost and fast test, this result may help to detect CI in everyday clinical practice.

Phenotype and genotype in 101 males with X-linked creatine transporter deficiency.

BACKGROUND: Creatine transporter deficiency is a monogenic cause of X-linked intellectual disability. Since its first description in 2001 several case reports have been published but an overview of phenotype, genotype and phenotype--genotype correlation has been lacking. METHODS: We performed a retrospective study of clinical, biochemical and molecular genetic data of 101 males with X-linked creatine transporter deficiency from 85 families with a pathogenic mutation in the creatine transporter gene (SLC6A8). RESULTS AND CONCLUSIONS: Most patients developed moderate to severe intellectual disability; mild intellectual disability was rare in adult patients. Speech language development was especially delayed but almost a third of the patients were able to speak in sentences. Besides behavioural problems and seizures, mild to moderate motor dysfunction, including extrapyramidal movement abnormalities, and gastrointestinal problems were frequent clinical features. Urinary creatine to creatinine ratio proved to be a reliable screening method besides MR spectroscopy, molecular genetic testing and creatine uptake studies, allowing definition of diagnostic guidelines. A third of patients had a de novo mutation in the SLC6A8 gene. Mothers with an affected son with a de novo mutation should be counselled about a recurrence risk in further pregnancies due to the possibility of low level somatic or germline mosaicism. Missense mutations with residual activity might be associated with a milder phenotype and large deletions extending beyond the 3' end of the SLC6A8 gene with a more severe phenotype. Evaluation of the biochemical phenotype revealed unexpected high creatine levels in cerebrospinal fluid suggesting that the brain is able to synthesise creatine and that the cerebral creatine deficiency is caused by a defect in the reuptake of creatine within the neurones.

Female gender and reproductive factors affecting risk, relapses and progression in multiple sclerosis.

Multiple sclerosis (MS), a chronic inflammatory demyelina-ting and degenerative disease of the central nervous system, is a frequent cause of neurological disability in young adults. Female predominance has increased over the last decades. Although female gender carries a higher risk of developing relapsing remitting MS, being female and at child-bearing age also appears to provide some protection against cognitive decline and against progressive onset MS, an adverse predictive factor when considering long-term disability in MS. The risk of MS in women has been associated with an earlier age at menarche. In most studies, parity did not impact MS risk. However, the recently published association of higher parity and offspring number with a reduced risk of a first demyelinating event suggests a potential suppressive effect. Pregnancy in MS patients has been associated with a reduced relapse rate and a reduction of neurological symptoms, especially in the third trimester. Despite the increased relapse risk in the postpartum period, there is no indication of an adverse effect of childbirth on the long-term course of MS. Fertility treatment in MS has been associated with an increased relapse risk in the following 3-month period, especially when the procedure did not result in pregnancy and gonadotrophin-releasing hormone agonists were used. Altogether, there is substantial evidence to support a regulatory role of sex steroid hormones in MS. In the absence of correlations with single hormone blood levels, we can only speculate about the underlying mechanisms. In conclusion, the increased MS risk in women and the changes in relapse and progression risk in association with reproductive events suggest significant and complex interactions between immune, neuroendocrine and reproductive systems in MS.

Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis.

BACKGROUND: Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS). OBJECTIVE: We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS. METHODS: We conducted a survey among persons with MS, registered by the Flemish MS society, Belgium, and stratified data according to relapsing-onset and progressive-onset MS. We used Kaplan-Meier survival and Cox proportional hazard regression analyses with time to Expanded Disability Status Scale (EDSS) 6 as outcome measure. Hazard ratios for the time from onset and from birth were calculated for the potentially predictive variables, adjusting for age at onset, gender and immunomodulatory treatment. RESULTS: 704 (51.3%) of the 1372 respondents had reached EDSS 6. In relapsing-onset MS, respondents reporting equal or higher levels of sun exposure than persons of the same age in the last 10 years had a decreased risk of reaching EDSS 6. In progressive-onset MS, increased sun sensitivity was associated with an increased hazard of reaching EDSS 6. CONCLUSION: The association of higher sun exposure with a better outcome in relapsing-onset MS may be explained by either a protective effect or reverse causality. Mechanisms underlying sun sensitivity might influence progression in progressive-onset MS.

Alcohol, coffee, fish, smoking and disease progression in multiple sclerosis.

BACKGROUND: Certain lifestyle factors might influence disease activity in multiple sclerosis (MS). OBJECTIVES: To investigate the consumption of alcoholic beverages, caffeinated drinks, fish and cigarette smoking in relation to disability progression in relapsing onset and progressive onset MS. METHODS: We conducted a cross-sectional survey amongst individuals with MS, registered by the Flemish MS society in Belgium. A time-to-event analysis and Cox proportional-hazard regression were performed with time to Expanded Disability Status Scale (EDSS) 6 (requiring a cane or support to walk for a distance of 100 m) as outcome measure. Hazard ratios for the time from onset and from birth were adjusted for age at onset, gender and immunomodulatory treatment. RESULTS: Data of 1372 persons with definite MS were collected. In the relapsing onset group, a decreased risk for reaching EDSS 6 was found in regular consumers of alcohol, wine, coffee and fish compared with those who never consumed these substances. Cigarette smoking was associated with an enhanced risk for reaching EDSS 6. In the progressive onset group, no association with the risk of reaching EDSS 6 was found, except for the type of fish. Preference for fatty fish was associated with an increased risk to reach EDSS 6, when lean fish was taken as the reference category. CONCLUSION: Consumption of alcoholic beverages, coffee and fish were inversely associated with progression of disability in relapsing onset MS, but not in progressive onset MS. These findings allow to support the hypothesis that different mechanisms might underlie progression of disability in relapsing and progressive onset MS.

Replication of KIF21B as a susceptibility locus for multiple sclerosis.

BACKGROUND: Knowledge of genetic susceptibility to autoimmune disorders is growing exponentially. One of the messages emerging from these data is the growing overlap in genetic susceptibility to different autoimmune disorders. KIF21B is a member of the kinesin superfamily and was recently established as a susceptibility locus for inflammatory bowel disease and for multiple sclerosis. RESULTS: We here replicate the association with multiple sclerosis in a Belgian study population of 791 patients and 1098 controls. CONCLUSION: As SNPs in KIF21B increase risk for both inflammatory bowel disease and multiple sclerosis, this suggests a common pathway in the pathogenesis of these diseases.

Harlequin syndrome in a pediatric population: a case series.

Harlequin syndrome is a rare condition, presenting with unilateral facial flushing and hyperhidrosis in response to physical exercise, heat or emotional stressors and has scarcely been reported in pediatric patients. It is caused by a dysfunction of vasomotor and sudomotor sympathetic fiber activity inhibiting the ability to flush on the affected side, causing the neurologically intact side to appear red. We present three pediatric cases of this uncommon syndrome, each of them of different origin and displaying distinct associated (neurological) symptoms, and review medical literature. Insight into the anatomical structure of the thoracocervical and facial sympathetic nervous system is pivotal as it dictates symptomatology. About half of Harlequin syndrome cases are complicated with ocular symptoms and a minority may be part of more extensive partial dysautonomias affecting facial sudomotor, vasomotor and pupillary responses, such as Holmes-Adie syndrome and Ross syndrome. Etiology is generally idiopathic, however, cases secondary to surgery, trauma or infection have been described. Considering its predominantly self-limiting nature, treatment is usually unnecessary and should be restricted to incapacitating cases.

Long-term effects of childbirth in MS.

BACKGROUND: The uncertainty about long-term effects of childbirth presents MS patients with dilemmas. METHODS: Based on clinical data of 330 female MS patients, the long-term effects of childbirth were analysed, using a cross-sectional study design. Four groups of patients were distinguished: (1) without children (n = 80), (2) with children born before MS onset (n = 170), (3) with children born after MS onset (n = 61) and (4) with children born before and after MS onset (n = 19). A time-to-event analysis and Cox proportional hazard regression were performed with time from onset to EDSS 6 and age at EDSS 6 as outcome measure. RESULTS: After a mean disease duration of 18 years, 55% had reached EDSS 6. Survival curves show a distinct shift in the time to EDSS 6 between patients with no children after MS onset and patients with children after MS onset in favour of the latter. Cox regression analysis correcting for age at onset shows that patients with children only after MS onset had a reduced risk compared with patients without children (HR 0.61; 95% CI 0.37 to 0.99, p = 0.049). Also, patients who gave birth at any point in time had a reduced risk compared with patients without children (HR 0.66; 95% CI 0.47 to 0.95, p = 0.023). A similar pattern was seen for age at EDSS 6 (HR 0.57, p = 0.027 and HR 0.68, p = 0.032 respectively) CONCLUSION: Although a bias cannot fully be excluded, these results seem to support a possible favourable long-term effect of childbirth on the course of MS.

Modifiable factors influencing relapses and disability in multiple sclerosis.

A growing body of literature indicates that the natural course of multiple sclerosis can be influenced by a number of factors. Strong evidence suggests that relapses can be triggered by infections, the postpartum period and stressful life events. Vaccinations against influenza, hepatitis B and tetanus appear to be safe. Surgery, general and epidural anaesthesia, and physical trauma are not associated with an increased risk of relapses. Factors that have been associated with a reduced relapse rate are pregnancy, exclusive breastfeeding, sunlight exposure and higher vitamin D levels. A number of medications, including hormonal fertility treatment, seem to be able to trigger relapses. Factors that may worsen progression of disability include stressful life events, radiotherapy to the head, low levels of physical activity and low vitamin D levels. Strong evidence suggests that smoking promotes disease progression, both clinically and on brain magnetic resonance imaging. There is no evidence for an increased progression of disability following childbirth in women with multiple sclerosis. Moderate alcohol intake and exercise might have a neuroprotective effect, but this needs to be confirmed.

Expanding CEP290 mutational spectrum in ciliopathies.

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.

Origin of fatigue in multiple sclerosis: review of the literature.

Fatigue is one of the most common and most disabling symptoms of multiple sclerosis (MS). Although numerous studies have tried to reveal it, no definite pathogenesis factor behind this fatigue has been identified. Fatigue may be directly related to the disease mechanisms (primary fatigue) or may be secondary to non-disease-specific factors. Primary fatigue may be the result of inflammation, demyelination, or axonal loss. A suggested functional cortical reorganization may result in a higher energy demand in certain brain areas, culminating in an increase of fatigue perception. Higher levels of some immune markers were found in patients with MS-related fatigue, whereas other studies rejected this hypothesis. There may be a disturbance in the neuroendocrine system related to fatigue, but it is not clear whether this is either the result of the interaction with immune activation or the trigger of this process. Fatigue may be secondary to sleep problems, which are frequently present in MS and in their turn result from urinary problems, spasms, pain, or anxiety. Pharmacologic treatment of MS (symptoms) may also provoke fatigue. The evidence for reduced activity as a cause of secondary fatigue in MS is inconsistent. Psychological functioning may at least play a role in the persistence of fatigue. Research did not reach consensus about the association of fatigue with clinical or demographic variables, such as age, gender, disability, type of MS, education level, and disease duration. In conclusion, it is more likely to explain fatigue from a multifactor perspective than to ascribe it to one mechanism. The current evidence on the pathogenesis of primary and secondary fatigue in MS is limited by inconsistency in defining specific aspects of the concept fatigue, by the lack of appropriate assessment tools, and by the use of heterogeneous samples. Future research should overcome these limitations and also include longitudinal designs.

Proxy ratings from multiple sources: disagreement on the impact of multiple sclerosis on daily life.

BACKGROUND AND PURPOSE: The use of self-report measurements may be problematic in patients with limitations that interfere with reliable self-assessment like cognitive impairment, as may be the case in multiple sclerosis (MS). In these situations proxy respondents, such as close relatives or healthcare providers, may provide valuable information. To examine the accuracy and value of healthcare providers and close relatives to assess disease impact of MS. METHODS: MS patients, close relatives and healthcare providers completed the Multiple Sclerosis Impact Scale (MSIS-29) before and after a rehabilitation program. Agreement between outcomes was assessed by calculating mean absolute and directional differences and intraclass correlation coefficients. RESULTS: Comparison of ratings between patients and proxy respondents revealed low levels of agreement. Close relatives appeared to significantly overestimate the disease impact of MS whereas healthcare providers tended to underestimate the disease impact of MS. CONCLUSION: Caution is advised when incorporating close relatives and healthcare providers as proxy respondents in a rehabilitation setting. However, when close relatives are consulted, one should expect a certain level of overestimation of disease impact. When consulting healthcare providers, one should expect a certain level of underestimation of disease impact.

P300 and treatment effect of modafinil on fatigue in multiple sclerosis.

To evaluate the value of visual and auditory P300 for predicting the response of multiple sclerosis-related fatigue to modafinil treatment, 33 patients were treated with 100 mg modafinil once daily for 4 weeks, following a 4-week baseline phase and an optional 8-week extension phase. The main clinical outcome parameter was a decrease in the fatigue visual analogue score (VAS) before and after 4 weeks of treatment. Patients with shorter auditory P300 latency at baseline were more likely to benefit from modafinil treatment. Auditory P300 latency predicted treatment response with a specificity of 76% and a sensitivity of 75% at a cut-off latency of 350 ms. Visual P300 latency could not be used to predict treatment response. Baseline auditory P300 latency predicted treatment response, whereas visual P300 latency did not. Clinical improvement did not correlate with changes in either visual or auditory P300.

FIFA's approach to doping in football.

BACKGROUND AND OBJECTIVES: FIFA's anti-doping strategy relies on education and prevention. A worldwide network of physicians guarantees doping control procedures that are straightforward and leave no place for cheating. FIFA actively acknowledges its responsibility to protect players from harm and ensure equal chances for all competitors by stringent doping control regulations, data collection of positive samples, support of research, and collaboration with other organisations. This article aims to outline FIFA's approach to doping in football. METHOD: Description of FIFA's doping control regulations and procedures, statistical analysis of FIFA database on doping control, and comparison with data obtained by WADA accredited laboratories as for 2004. RESULTS: Data on positive doping samples per substance and confederation/nation documented at the FIFA medical office from 1994 to 2005 are provided. According to the FIFA database, the incidence of positive cases over the past 11 years was 0.12%, with about 0.42% in 2004 (based on the assumption of 20,750 samples per year) and 0.37% in 2005. Especially important in this regard is the extremely low incidence of the true performance enhancing drugs such as anabolic steroids and stimulants. However, there is a need for more consistent data collection and cross checks among international anti-doping agencies as well as for further studies on specific substances, methods, and procedures. With regard to general health impairments in players, FIFA suggests that principles of occupational medicine should be considered and treatment with banned substances for purely medical reasons should be permitted to enable players to carry out their profession. At the same time, a firm stand has to be taken against suppression of symptoms by medication with the aim of meeting the ever increasing demands on football players. CONCLUSION: Incidence of doping in football seems to be low, but much closer collaboration and further investigation is needed with regard to banned substances, detection methods, and data collection worldwide.

Small deletions occur in highly conserved regions of the LAZ3/BCL6 major translocation cluster in one case of non-Hodgkin's lymphoma without 3q27 translocation.

The LAZ3/BCL6 gene encoding a Zinc-finger nuclear protein is altered in Non-Hodgkin's Lymphomas (NHLs) by translocations, mutations and/or deletions clustered in its 5' non coding region, in a 3.3 Kbp EcoRI fragment which thus defines the Major Translocation Cluster (MTC). In the present study, we describe at the molecular level the deletions found in the MTC of two (NHL) cases using, (i) DNA obtained from a patient (GUI) with a monosomy 3 and three microdeletions of 101, 22, 25 bp in its unique untranslocated 3q27 allele; (ii) a cell line derived from a patient (VAL) carrying a t(3;4) (q27;p11) translocation and a 2.4 Kbp deletion in the untranslocated allele. As the MTC is recurrently subject to alterations, we have cloned and sequenced the murine equivalent of the human MTC and promoter region in an attempt to identify sequences well conserved in mammals that may be thus important for the LAZ3/BCL6 gene regulation. We show that the human and mouse 5' upstream regions of the LAZ3/BCL6 gene although mainly intronic share a particularly high homology of 79% on the overall sequence. Strikingly, the small sequences which are deleted in patient (GUI) are highly conserved (81%, 100% and 92% respectively). Furthermore, they may play a role in the pathogenesis since proteins prepared from B cell lines and HeLa nuclear extracts bind to these sequences in gel retardation assays. Although a large part of this region is intronic, the high conservation of its sequence and the frequency of alterations in NHLs suggest that they are likely to be significant for the regulation of the LAZ3/BCL6 gene.

TTF, a gene encoding a novel small G protein, fuses to the lymphoma-associated LAZ3 gene by t(3;4) chromosomal translocation.

We have previously shown that the LAZ3/BCL6 gene encoding a potential transcription factor, is disrupted in B-diffuse large cell non-Hodgkin's lymphomas (NHL) with 3q27 chromosomal abnormalities involving the immunoglobulin (IG) genes. However, LAZ3 rearrangement also occurs in NHL bearing 3q27 translocations without involvement of the IG genes: for example the VAl cell line exhibits t(3;4)(q27;p11). In the present work we have used a RT-PCR method to detect and to sequence the LAZ3 mRNA products from the VAL cell line. We report that the consequence of the t(3;4) is the expression of a chimeric transcript of LAZ3 with a new gene encoding a small G-like protein, termed TTF (Translocation Three Four). Nucleotide sequence analysis of a 1.4 kb cDNA predicts that the TTF gene encodes a protein of 191 amino-acids similar to members of the RAS superfamily including HRAS (27% identical), RAB1A (30% identical) and RHO proteins: the human RAC1, RHOB and CDC42Hs proteins (respectively 43, 44 and 45% identical) and the yeast RHO2 protein (44% identical). Unlike most other small G proteins which are expressed ubiquitously, TTF was transcribed only in hemopoietic cells as a 2.2 kb transcript. TTF may define a new subgroup of RHO-like proteins.