Assessing causality in financial time series

We develop new classes of semiparametric multivariate time series models based on Multi-Output Gaussian Processes and warped Multi-Output Gaussian Processes. These describe relationships between a current vector of observations and the lagged history of each marginal time series. We encode a serial dependence structure through mean and covariance functions and introduce a more complex dependence structure using copulas to couple each warped marginal Gaussian process. Within this class of models our primary goal is to detect causality and to study the interplay between the causal structure and the dependence structure. We do not, however, require true representation of the data generating process, but we model structural hypotheses regarding how causality may have manifested in the observed vector valued processes. With our framework we test the dependence with regards to the structures that are specified, and can use testing for causality under different model assumptions as a way to explore the data and the potentially complex dependence relationships. To perform the testing we consider several families of causality testing and develop compound tests which first require estimation/calibration of the mean and covariance functions parametrising the nonparametric vector valued time series. Our approach allows very general nonlinear dependence and causal relationships which are not often considered in classical parametric time series models, including causality in higher order information and joint extreme dependence features. We provide a generic framework which can be applied to a variety of different problem classes and discuss a number of examples to illustrate the ideas developed. Throughout, we will consider, without loss of generality, two multivariate time series denoted by X_t in R^d, Y_t in R^d' where one may assume, for instance, that these have been generated by observing partial realisations of a generalised diffusion processes: dX_t = mu_X(t, X_t^{-k}, Y_t^{-l}, Z_t^{-m}) dt + Sigma_X(t, X_t^{-k}, Y_t^{-l}, Z_t^{-m}) dW_t dY_t = mu_Y(t, X_t^{-k}, Y_t^{-l}, Z_t^{-m}) dt + Sigma_Y(t, X_t^{-k}, Y_t^{-l}, Z_t^{-m}) dW'_t, where Z_t, which may or may not be included, is some real process that we will call side information, dW_t, dW'_t are two different Brownian motions, possibly with marginal serial correlation and/or instantaneous cross-correlation. All of those processes are only partially observed, and may be sampled at irregular intervals. The form of drift and volatility described by the diffusion equation means that the processes X_t and Y_t can be conditionally dependent on each other, and this dependence can be introduced through both the drift and the volatility. Such generalised diffusion models can induce in the marginal process between X_t and Y_t different types of extremal dependence, depending on the forms of the drift and volatility functions. We propose a smooth stochastic process statistical model to capture the smooth variation of the partially observed time series represented by data X_t, Y_t, Z_t using multiple output Warped Gaussian Process models. In this work we are interested in partial observations of these processes, for which the partially observed time series of X_t and Y_t will have different types of extremal dependence characteristics. We wish to detect the presence or absence of statistical causality where such extremal dependence features may or may not obfuscate the ability to detect causality in nonlinear partially observed time series models. The rationale for developing a semiparametric solution for modelling the partially observed time series is that we may accommodate, through the use of Gaussian Process models, a wide variety of features for the hypotheses about the trends and volatility and importantly their possible causal structures, which can be formally tested in our framework. Furthermore the use of Warped Gaussian Process models allows to incorporate higher order dependence such as extremal tail dependence features. Statistical Causality. The notion of causality that lies at the centre of our research is the concept of statistical causality, based on comparing two predictive models. Quoting Wiener [1956]: "For two simultaneously measured signals, if we can predict the first signal better by using the past information from the second one than by using the information without it, then we call the second signal causal to the first one". The null hypothesis of no causal relationship from time series X_t to Y_t means that including the past of X_t does not improve the prediction of future of Y_t. In a most general form this can be written as equality of conditional distribution of Y, conditioning on either set of explanatory variables (X_t^{-k}, Y_t^{-l}, Z_t^{-m}) denote past of the X_t, Y_t, Z_t time series up to lags k,l,m respectively): H_0: p(Y_t | X_{t-1}^{-k}, Y_{t-1}^{-l}, Z_{t-1}^{-m}) = p(Y_t \mid Y_{t-1}^{-l}, \bZ_{t-1}^{-m}) H_1: p(Y_t | X_{t-1}^{-k}, Y_{t-1}^{-l}, Z_{t-1}^{-m}) p(Y_t \mid Y_{t-1}^{-l}, \bZ_{t-1}^{-m}). The type of casual dependence that is described by statistical causality is a mechanism that occurs at multiple lags over time - which could have been triggered by a sequence of processes, not an individual one. It can help to gain an insight into both cross-sectional and temporal dynamics of the data analysed. Warped Multi-Output Gaussian Processes. A Gaussian process is a Markov process, such that all finite dimensional distributions are Gaussian. While Gaussian processes models can accommodate wide range of properties and are very attractive for their easy implementation and optimisation, but they do not allow higher order dependence such as extremal tail dependence features. One way to generalise Gaussian process models so that higher order dependence can be handled, is to apply a transformation to the joint collection of Gaussian processes for each marginal time series model. We apply mean-variance transformation that results in the transformed variables having multivariate skew-t distributions and being finite dimensional realisations of a general multivariate skew-t process. Motivation for the Model Choice. There are numerous advantages of using Gaussian Processes, beginning with: ease of optimisation and interpretability of hyperparameters, flexibility, richness of covariance functions, allowing for various model structures. Using a likelihood ratio type test with a GP is a very natural choice, as estimating GP model parameters is often done on the basis of maximising likelihood, and therefore this estimation can be incorporated into the compound version of the likelihood ratio test (Generalised Likelihood Ratio Test, GLRT). From Gaussian variables, GPs inherited the property of being fully specified by the mean and the covariance, and so testing for model equivalence inherently means testing for equivalence of the mean and covariance functions. But many popular kernels do not have the ARD property, and using them for a likelihood ratio test settings gives no easy way to account for causal structures in covariance. Consequently, it is using GLRT with an ARD-GP that gives a uniformly most powerful test with an unparalleled flexibility: known asymptotic distribution under the null, explicit evaluation and in a closed form, and usefulness also for misspecified models. The proposed use of copula warping allows introduction of additional dependence, in particular tail dependence, while keeping the likelihood in closed form. Application. We provide a generic framework which can be applied to a wide range of problems, and which can be readily tailored or further extended. The illustrative examples included demonstrate how a range of data properties can be encoded in the model, and how they might affect the detection of causality. We present two real data application: to commodity futures data and inflation and interest rates. We show how the framework can be used in practice, and how it can be combined with, or enhance, more common approaches to analysing financial time series. Our observations are in line with financial interpretations, but they also offer additional insight and pose thought-provoking questions. Structure of the thesis. This thesis presents the research as it evolved: starting from an overview of a range of the causality methods already known, and demonstrating out why they are unsatisfactory. Subsequently, a new approach is presented -- a method based on Gaussian processes, that was developed to solve the drawbacks of the methods presented in the first part. Afterwards, an extension is proposed to widen the range of dependence structures, as well as marginal properties of the data that can be incorporated. Chapter 1 introduces the topic of the thesis, and reviews relevant literature. Chapter 2 discusses philosophical roots of the concept of statistical causality, as well as alternative notions of causality. After illustrating some of the varied ways of conceptual representation of causality, we present four distinct ways of modelling statistical causality. Chapter 3 contains background on the models considered: Gaussian processes, copulas and selected distributions. Chapter 4 describes inference procedures used: assessing hypothesis tests, generalised likelihood ratio test, permutation tests, and likelihood ratio test. The second part, New Perspectives on Causality Representation and Inference, presents the main contribution of our work. It starts with Chapter 5 containing the theoretical background for describing and testing causality with GP models. Chapter 6 extends the model from the previous chapter by introducing mean-variance transformation that results in a warped GP model, which can describe causality in the presence of skewness and tail dependence. Chapter 7 describes how synthetic data has been simulated, details the algorithm for approximating likelihood in the warped GP, and provides information on other relevant algorithms and the software used to implement our method. Chapter 8 presents an extensive experiment section, which aim to show, firstly, the good behaviour of the proposed procedures (model sensitivity and misspecification analysis), secondly, good power of the test for a range of structures, and, thirdly, the interaction of causality and tail dependence. Applications to real-world data are described in Chapter 9, where time series for commodities and currency markets are analysed. Finally, Chapter 10 presents the conclusions and directions for further development, and Appendices provide supplementary material

Chapter 1 Transformation of the economy

"This book presents the ways in which three key issues of the modern world – transformation, digitalisation and sustainability – may be combined for the greater good and highlights which activities may be designed to integrate these three directly linked paths. It is an experience-derived and evidence-based analysis of how sustainable development impacts the transformation of the economy and how the business environment influences economic transformation in the light of the sustainable development principles. The book addresses the current challenges and shows how the economy can be transformed further in an organic way that meets the needs of society and the environment, through the use of digital technologies. The multidisciplinary approach to sustainability transformation is one of the core strengths of the book, as it emphasises the need for a holistic approach to the functioning of sustainable development ideas at the micro- and macro-levels. The authors present a fresh perspective, particularly around the regulations stimulating the sustainable development of enterprises, tax systems, and the allocation of capital. Moreover, the book brings together and makes available the results of the latest research on the subject, using a vast amount of primary evidence and both quantitative and qualitative methodology. The authors’ insights go beyond the obvious effects of economic transformation and call attention to ways in which smart technology and digitalisation may help to achieve the Sustainable Development Goals. The book is directed first and foremost towards academics, researchers and students, but also professionals, who would like to expand their knowledge of sustainable development from a scientific perspective.

Predicting the performance of equity anomalies in frontier emerging markets: a Markov switching model approach

Equity anomalies in frontier markets appear and disappear over time. This article aims to demonstrate the predictability of which of these transient anomalies will be profitable using a Markov switching model. To do so, we examine 140 equity anomalies identified in the literature using a unique sample of over 3,600 stocks from 23 frontier equity markets between 1997 and 2016. The application of a Markov switching model reveals that the time-series pattern of expected returns is dependent upon the type of anomaly; some anomalies become unprofitable over time whereas profitability increases in tandem with the development of a specific stock market for other types of anomalies. Results further indicate that forecasts of the next month’s return obtained from this model can translate into profitable investment strategies. We find that an anomaly selection strategy that relies on the model produces abnormal returns and outperforms a naïve benchmark that considers all the anomalies. We go onto demonstrate that our results are robust

Визначення ефективності безпеки польотів аналітичною моделлю

The implementation of maximum flight safety to supervised flight and airport objects with all modern tracking and control means is currently difficult if we do not know how well the whole structural architecture of these buildings works. The need to increase the level of safety of aeronautical operational objects in various time, space and climatic conditions creates the need to extend the functions of safety devices not only in the field of physical principles but also in the way of their quality assessment. The article deals with the possibility of evaluating process safety management, which is made visible by a multi-level hierarchical structure. High reliability of security management at individual levels does not express the quality of their functions but their ability to solve the submitted tasks. The functions of flight safety systems designed for their practical applicability to aircraft and airports and the adaptation of man-operator create specialized safety complexes whose errors are removed by the operator controlling their functions. Significant in the analysis of the effectiveness and safety of aeronautical systems are the terms in the article that represent inputs to modelling. These terms in principle accept reciprocity distribution of synthetic or natural achievements that are the source of information for managing the safety of the aviation object by the human operator. Together they create reciprocity linked to flight safety limits, which can be verified not only in air transport but also in aviation laboratories, for example. Therefore, each flight safety has a defined range of usability, which is also limited by functional safety and efficiency. It is shown in the paper that the process of increasing the reliability of the hierarchical structure of organizing security must be linked to quality, the criteria of which determine the correlation degree. Efficiency in managing operational flight processes creates a prerequisite for success in any area of controlled flight processes. The quality of organizing a controlled flight process is evaluated by the functional efficiency of managing the entire flight operation.Обеспечение максимальной безопасности полетов на подконтрольных летательных и наземных объектах аэропортов с использованием всех современных средств наблюдения и контроля в данное время является достаточно сложным заданием, в случае, когда не известно, на сколько хорошо работает вся структура этих объектов. Необходимость повышения уровня безопасности авиационных объектов эксплуатации при разных часовых, пространственных и климатических условиях формирует потребность в расширении функций средств безопасности не только в области физических принципов, но и в направлении оценки их качества. В статье рассмотрено возможность оценивания процесса управления безопасностью с применением многоуровневой иерархической структуры. Высокая надежность управления безопасностью на отдельных уровнях выражает не качества ее функций, а способность решать поставленные задачи. Функции систем безопасности полетов, предназначенные для их практической пригодности на авиационных суднах и в аэропортах, а также для адаптации персонала, формируют специализированные комплексы безопасности, ошибки которых могут быть устранены оператором, который контролирует эти функции. Важными для анализа эффективности и безопасности авиационных систем являются определения в данной статье, которые представляют входящие данные для моделирования. Эти определения в принципе представляют распределение взаимосвязи искусственных либо природных достижений, которые являются источником информации для управления безопасностью авиационного объекта человеком-оператором. Вместе они формируют взаимосвязь, связанную с границами безопасности полетов, которые, например, могут быть верифицированы не только на авиационном транспорте, но и в авиационных лабораториях. Таким образом, каждый вид безопасности полетов имеет определенный диапазон удобства использования, который также ограничен функциональной безопасностью и эффективностью. В роботе показано, что процесс повышения надежности иерархической структуры организации безопасности должен быть связан с качеством, критерии которого определяют степень корреляции. Эффективность управления процессами полета создает предпосылки для успеха в любой области контролируемых полетных процессов. Качество организации контролируемого процесса полета оценивается по функциональной эффективности управления всей процедурой полета.Забезпечення максимальної безпеки польотів на підконтрольних літальних та наземних об'єктах аеропортів з використанням усіх сучасних засобів спостереження та контролю в даний час є досить важким завданням, у випадку, коли не відомо, наскільки добре працює вся структура цих об’єктів. Необхідність підвищення рівня безпеки авіаційних об'єктів експлуатації за різних часових, просторових і кліматичних умовах створює потребу у розширенні функцій засобів безпеки не тільки в області фізичних принципів, але й у напрямі оцінки їх якості. У статті розглянуто можливість оцінювання процесу управління безпекою, із застосуванням багаторівневої ієрархічної структури. Висока надійність управління безпекою на окремих рівнях виражає не якості її функцій, а здатність вирішувати поставлені завдання. Функції систем безпеки польотів, призначені для їх практичної придатності на авіаційних суднах та в аеропортах, а також для адаптації персоналу, створюють спеціалізовані комплекси безпеки, помилки яких можуть бути усунені оператором, що контролює ці функції. Важливими для аналізу ефективності та безпеки авіаційних систем є терміни в даній статті, що представляють вхідні дані для моделювання. Ці терміни в принципі представляють розподіл взаємозв’язку штучних або природних досягнень, які є джерелом інформації для управління безпекою авіаційного об'єкта людиною-оператором. Разом вони створюють взаємозв’язок, пов'язаний з межами безпеки польотів, які, наприклад, можуть бути верифіковані не тільки на авіаційному транспорті, але і в авіаційних лабораторіях. Таким чином, кожен вид безпеки польотів має певний діапазон зручності використання, який також обмежений функціональною безпечністю та ефективністю. У роботі показано, що процес підвищення надійності ієрархічної структури організації безпеки повинен бути пов'язаний з якістю, критерії якої визначають ступінь кореляції. Ефективність управління процесами польоту створює передумови для успіху в будь-якій області контрольованих польотних процесів. Якість організації контрольованого процесу польоту оцінюється за функціональною ефективністю управління всією операцією польоту

Expression of proteins associated with therapy resistance in rhabdomyosarcoma and neuroblastoma tumour cells

The activity of multidrug resistance (MDR) proteins in tumour cells is associated with an increased resistance to therapy and in consequence with a decreased effectiveness of chemotherapy. The majority of MDR molecules belong to a family of ABC (ATP binding cassette) transporters. Neuroblastoma (NBL) and rhabdomyosarcoma (RMS) are common solid tumours of childhood. The response to therapy is better in NBL, worse in RMS, but still unsatisfactory despite surgery and aggressive chemotherapy. The immunohistochemical staining for p-gp (p-glycoprotein), MRP1 (multidrug resistance associated protein 1), BCRP (breast cancer resistance protein) and LRP (lung resistance protein) expression was performed in primary tumour sections of NBL (10 cases) and RMS (10 cases). A different pattern of MDR expression in NBL and RMS were noted. In NBL, MRP1 was expressed in all studied tumours, p-gp, BCRP only in 3 out of 10 tumours, LRP, in 4 cases. The combination of more than one protein was noted in the majority of NBL tumours. In RMS, the expression of 3 or 4 MDR proteins was noted in 9 cases. The high expression of an MDR protein profile in RMS suggests various mechanisms acting simultaneously, which might explain chemotherapy resistance and a low percentage of long-time survival in this tumour

Various cardio-vascular risk and new safety recommendations in the treatment of non-steroidal anti-inflammatory drugs

Niesteroidowe leki przeciwzapalne (NLPZ) należą do najczęściej przepisywanych leków na świecie. Na podstawie systematycznych przeglądów i metaanaliz ostatnich lat stwierdzono, że terapia NLPZ wiąże się ze zróżnicowanym poziomem ryzyka sercowo-naczyniowego (np. zawałem serca, niewydolnością serca lub udarem niedokrwiennym) odnotowywanego zarówno u osób z chorobami układu krążenia, jak i bez nich, leczonych NLPZ. Z badań wynika, że stosowanie diklofenaku może być przyczyną wysokiego ryzyka powikłań sercowo-naczyniowych. Zróżnicowanie klasycznych NLPZ pod względem profilu ryzyka sercowo-naczyniowego mogą wyjaśniać różnice w powinowactwie do cyklooksygenaz COX-1 i COX-2 oraz wpływ na równowagę pomiędzy syntezą prostacykliny PGI2 a tromboksanem A2. Ponadto poziom ryzyka zależy od stosowanej dawki, czasu trwania leczenia i formulacji leku. Dlatego nowe zalecenia bezpieczeństwa dla diklofenaku, które mają zminimalizować zagrożenia ze strony układu krążenia, rekomendują stosowanie leku w najniższej skutecznej dawce dziennej (< 150 mg) przez możliwie najkrótszy okres wymagany do opanowania objawów. Względnie niskie ryzyko sercowo-naczyniowe potwierdzono jedynie dla naproksenu, dlatego lek może stanowić alternatywę dla pacjentów, których leczenie NLPZ jest wskazane. Lekarze zlecający terapię lekami z grupy NLPZ powinni brać pod uwagę indywidualny profil ryzyka sercowo-naczyniowego pacjenta oraz starannie rozważyć stosunek korzyści do zagrożeń, jakie mogą wystąpić w wyniku leczenia.Non-steroidal anti-inflammatory drugs (NSAIDs) have become some of the most frequently used drugs throughout the world. Several recent systematic reviews and meta-analyses indicates, that NSAIDs are associated with variable levels of cardiovascular risk (CV) (myocardial infarction, heart failure or ischemic stroke), observed both in people with high risk of cardiovascular disease and in healthy individuals. Diclofenac is the agent most associated with an increased risk among others members of the class. Research suggests it could be related to the inhibition of COX-2, coupled with an incomplete inhibition of COX-1 and altering the prostaglandin PGI2-thromboxane TxA2 balance. The CV risk is also dose-, time- and formulation-dependent. Therefore, short duration of treatment, safe and effective daily dose (< 150 mg) of diclofenac are recommend according to new safety recommendations, which are intended to minimize the CV risk. Naproxen because of the safest cardiovascular risk profile could be an alternative, when NSAID treatment can’t be avoided. Physicians initiating any NSAIDs treatment should consider the patient’s risk profile and make an individual assessment of cardiovascular risk and carefully consider the balance between benefit and CV risk

Niesteroidowe leki przeciwzapalne – fakty, mity i kontrowersje dotyczące ryzyka sercowo-naczyniowego oraz ryzyka powikłań ze strony przewodu pokarmowego

Niesteroidowe leki przeciwzapalne (NLPZ) są jedną z najpowszechniej stosowanych grup leków z uwagi na ich przeciwzapalne, przeciwgorączkowe i przeciwbólowe działania, które są pożądane i przynoszą korzyści w wielu schorzeniach. Zastosowanie NLPZ ogranicza jednak wysoka częstość występowania działań niepożądanych, szczególnie dotyczących przewodu pokarmowego i układu krążenia. Farmakoterapia NLPZ polega na balansowaniu między gastro- i kardio- toksycznością i powinna opierać się na ocenie korzyści i profilu bezpieczeństwa leku indywidualnie u każdego chorego. Obecnie toczy się debata dotycząca bezpieczeństwa kardiologicznego, nie tylko selektywnych inhibitorów cyklooksygenazy-2 (COX-2), ale również klasycznych, nieselektywnych NLPZ. Przegląd badań klinicznych zamieszczony w poniższym artykule stanowi ocenę ryzyka i korzyści płynących z terapii NLPZ i próbę ustalenia, czy mamy w tym względzie do czynienia z „efektem klasy”, czy też istnieją różnice w profilu bezpieczeństwa nie tylko pomiędzy klasycznymi NLPZ i selektywnymi inhibitorami COX-2, ale również w każdej z tych grup z osobna. Dowody wskazują, że inhibitory COX-2 są związane z istotnie mniejszą częstością występowania wrzodów żołądka i dwunastnicy w porównaniu do tradycyjnych NLPZ. Jednak ten korzystny efekt jest minimalizowany, gdy pacjent stosuje równocześnie niskie dawki kwasu acetylosalicylowego. Zarówno COX-2 inhibitory jak również klasyczne NLPZ mogą zwiększać ryzyko sercowo - naczyniowe. Ryzyko sercowo - naczyniowe zależy od rodzaju NLPZ, wielkości dawki i czasu leczenia. Z niskimi dawkami celekoksybu prawdopodobnie wiąże się mniejsze ryzyko sercowo -naczyniowe, aczkolwiek wymaga to dodatkowego potwierdzenia w badaniach klinicznych o wysokiej wiarygodności, które obecnie są w toku

MLPA based detection of mutations in the dystrophin gene of 180 Polish families with Duchenne/Becker muscular dystrophy

Duchenne/Becker muscular dystrophy (DMD/BMD) is a recessive, X-linked disorder caused by a mutation in the dystrophin gene. Deletions account for approximately 60–65% of mutations, duplications for 5–10%. The remaining cases are mainly point mutations. According to Monaco theory clinical form of the disease depends on maintaining or disrupting the reading frame. The purpose of the study was to determine frequency and location of deletions and duplications in the dystrophin gene, to determine the compliance between maintaining/disrupting the reading frame and clinical form of the disease and to check the effectiveness of MLPA (multiplex ligation-dependent probe amplification) in the detection of these mutations in hemizygous patients and heterozygous female carriers. The material is composed of combined results of molecular diagnosis carried out in years 2009–2012 in 180 unrelated patients referred with the diagnosis of DMD/BMD tested by use of MLPA. We identified 110 deletions, 22 duplication (in one patient two different duplications were detected) and 2 point mutations. Deletions involved mainly exons 45–54 and 3–21, whereas most duplications involved exons 3–18. The compliance with Monaco theory was 95% for deletions and 76% for duplications. Most of mutations in the dystrophin gene were localized in the hot spots – different for deletions and duplications. MLPA enabled their quick identification, exact localization and determination whether or not they maintained or disrupted the reading frame. MLPA was also effective in detection of deletions and duplications in female carriers

Evaluation of the In vitro cytotoxic activity of caffeic acid derivatives and liposomal formulation against pancreatic cancer cell lines

Pancreatic cancer belongs to the most aggressive group of cancers, with very poor prognosis. Therefore, there is an important need to find more potent drugs that could deliver an improved therapeutic approach. In the current study we searched for selective and effective caffeic acid derivatives. For this purpose, we analyzed twelve compounds and evaluated their in vitro cytotoxic activity against two human pancreatic cancer cell lines, along with a control, normal fibroblast cell line, by the classic MTT assay. Six out of twelve tested caffeic acid derivatives showed a desirable effect. To improve the therapeutic efficacy of such active compounds, we developed a formulation where caffeic acid derivative (7) was encapsulated into liposomes composed of soybean phosphatidylcholine and DSPE-PEG2000. Subsequently, we analyzed the properties of this formulation in terms of basic physical parameters (such as size, zeta potential, stability at 4 °C and morphology), hemolytic and cytotoxic activity and cellular uptake. Overall, the liposomal formulation was found to be stable, non-hemolytic and had activity against pancreatic cancer cells (IC50 19.44 µM and 24.3 µM, towards AsPC1 and BxPC3 cells, respectively) with less toxicity against normal fibroblasts. This could represent a promising alternative to currently available treatment options

Evidence for a relatively high proportion of DM2 mutations in a large group of Polish patients

Introduction: Myotonic dystrophies (DMs) type 1 (DM1) and type 2 (DM2) are autosomal dominant, multisystem disorders, considered the most common dystrophies in adults. DM1 and DM2 are caused by dynamic mutations in the DMPK and CNBP genes, respectively. Methods: Molecular analyses were performed by PCR and the modified RP-PCR in patients, in their at-risk relatives and prenatal cases. Results: The analysis of Polish controls revealed the range of 5-31 CTG repeats for DM1 and 110-228 bp alleles for DM2. Among 318 confirmed probands - 196 (62%) were DM1 and 122 (38%) – DM2. Within DM1families, 10 subjects carried a low expanded CTG tract (< 100 repeats), which resulted in a full mutation in subsequent generations. Two related individuals had unstable alleles–188 bp and 196 bp without common interruptions. Conclusion: The relative frequencies of DM1/DM2 among Polish patients were 68% and 32%, respectively, with a relatively high proportion of DM2 mutations (1.6:1)