Postać dziedziczna choroby prionowej w Polsce

Background and purpose The aim of the study was to perform molecular analysis in a group of patients affected with prion disease. Diagnosis was based on results of clinical and/or histopathological examination of the brain. This is the largest investigation of this type performed so far in Poland. Material and methods Analysed material contained 36 cases of prion disease, including 35 cases of Creutzfeldt-Jakob disease and one case of Gerstmann-Sträussler-Scheinker disease, as well as two familial cases initially suspected of Huntington disease and Alzheimer disease. The control group consisted of 87 subjects. The most frequent known mutations in the PRNP gene were looked for, namely those in codons 102, 117, 178, 200, 217 and OPRI; the polymorphism Met/Val in codon 129 was also analysed. The methods applied were PCR-RFLP and DNA sequencing. Results The following mutations were found: E200K in 5 families, P102L in one family (previously identified), D178N in one family and 6OPRI in one family. Overall, mutations were detected in 17 persons (including 8 preclinical ones) from 8 pedigrees. Highly significant difference of codon 129 Met/Val heterozygosity frequencies was found between the affected subjects and the controls. Frequency of the familial form of prion disease in the material analysed was 14%. Conclusions Screening for mutations in the PRNP gene should be performed in all diagnosed cases of prion disease and cases of familial occurrence of early onset dementia of unknown aetiology. Families with identified mutations should be offered genetic counselling and informed of risks of blood and organs’ donation.Wstęp i cel pracy Celem pracy była analiza molekularna w grupie osób dotkniętych chorobą prionową, rozpoznaną na podstawie objawów klinicznych i/lub wyniku badania neuropatologicznego mózgu. Było to największe tego typu badanie przeprowadzone dotychczas w Polsce. Materiał i metody W skład analizowanego materiału weszło 36 przypadków choroby prionowej, w tym 35 przypadków choroby Creutzfeldta-Jakoba i jeden przypadek choroby Gerstmanna-Sträusslera-Scheinkera, a także dwa przypadki rodzinne podejrzane o chorobę Huntingtona i chorobę Alzheimera oraz grupa kontrolna (87 osób). Poszukiwano najczęstszych mutacji w genie PRNP: wkodonach 102, 117, 178, 200, 217 i OPRI. Kodon 129 analizowano również pod kątem zygotyczności (walina/metionina). Stosowano metodę PCR-RFLP i sekwencjonowanie. Wyniki Wykryto mutacje: E200K – pięć rodzin, P102L – jedna rodzina (wcześniej zidentyfikowana), D178N – jedna rodzina, 6OPRI – jedna rodzina. Łącznie stwierdzono mutację w 8 rodowodach u 17 osób, w tym u 8 osób w fazie przedobjawowej. Zaobserwowano także bardzo istotną różnicę w częstości występowania heterozygotyczności Met/Val pomiędzy grupą badaną i grupą kontrolną. Częstość dziedzicznej postaci choroby prionowej w analizowanym materiale wynosi 14%. Wnioski Mutacji w genie PRNP należy poszukiwać we wszystkich przypadkach choroby prionowej oraz w przypadkach rodzinnie występującego otępienia o wczesnym początku i niewyjaśnionej etiologii. Przebieg kliniczny i zmiany neuropatologiczne w niektórych przypadkach dziedzicznych chorób prionowych mogą się różnić od spotykanych najczęściej w sporadycznej postaci choroby. Rodziny ze stwierdzoną mutacją winny być objęte poradnictwem genetycznym i poinformowane o zagrożeniu związanym z dawstwem krwi i narządów do przeszczepienia

Peripheral nerve involvement in myotonic dystrophy type 2 – similar or different than in myotonic dystrophy type 1?

Introduction Multisystem manifestations of myotonic dystrophies type 1 (DM1) and 2 (DM2) are well known. Peripheral nerve involvement has been reported in DM1 but not in genetically confirmed DM2. The aim of our study was to assess peripheral nerve involvement in DM2 using nerve conduction studies and to compare these results with findings in DM1. Methods We prospectively studied patients with genetically confirmed DM2 (n=30) and DM1 (n=32). All patients underwent detailed neurological examination and nerve conduction studies. Results Abnormalities in electrophysiological studies were found in 26.67% of patients with DM2 and in 28.13% of patients with DM1 but the criteria of polyneuropathy were fulfilled in only 13.33% of patients with DM2 and 12.5% of patients with DM1. The polyneuropathy was subclinical, and no correlation was found between its presence and patient age or disease duration. Conclusions Peripheral nerves are quite frequently involved in DM2, but abnormalities meeting the criteria of polyneuropathy are rarely found. The incidence of peripheral nerve involvement is similar in both types of myotonic dystrophy

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)

The personal experience of parenting a child with Juvenile Huntington’s Disease: perceptions across Europe

The study reported here presents a detailed description of what it is like to parent a child with juvenile Huntington’s disease in families across four European countries. Its primary aim was to develop and extend findings from a previous UK study. The study recruited parents from four European countries: Holland, Italy, Poland and Sweden,. A secondary aim was to see the extent to which the findings from the UK study were repeated across Europe and the degree of commonality or divergence across the different countries. Fourteen parents who were the primary caregiver took part in a semistructured interview. These were analyzed using an established qualitative methodology, interpretative phenomenological analysis. Five analytic themes were derived from the analysis: the early signs of something wrong; parental understanding of juvenile Huntington’s disease; living with the disease; other people’s knowledge and understanding; and need for support. These are discussed in light of the considerable convergence between the experiences of families in the United Kingdom and elsewhere in Europe

Zagrożenia zdrowotne wśród dzieci i młodzieży. T. 3

Praca recenzowana / Peer-reviewed pape

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Szybkie wykrywanie dużych ekspansji w postępującej padaczce mioklonicznej typu 1, dystrofii miotonicznej typu 2 i ataksji rdzeniowo-móżdżkowej typu 8

Background and purpose Human genetic disorders associated with multiple unstable repeats resulting in long DNA expansions are difficult to identify by conventional polymerase chain reaction (PCR) in routine molecular testing, and therefore require time-consuming hybridisation. To improve and expedite the diagnostic methods for progressive myoclonus epilepsy (EPM1), myotonic dystrophy 2 (DM2) and spinocerebellar ataxia 8 (SCA8) caused by dynamic mutations, we adapted a repeat primed PCR (RP-PCR) assay which was previously developed for testing of other triplet repeat disorders. Material and methods The new algorithm for molecular analysis was to run a standard PCR to yield alleles in an amplifiable range and then run a RP-PCR to detect larger expansions. Electrophoresis and visualisation of PCR products on an automatic sequencer were applied to determine normal and pathogenic alleles comprising (C4GC4GCG)n in EPM1 in 44 subjects, (CCTG)n in DM2 in 76 individuals and (CTG)n in SCA8 in 378 patients. Results: The protocol combining conventional PCR and RP-PCR proved to be a rapid and reliable test to diagnose the above named disorders. Among 44 individuals tested for EPM1, two expanded alleles were identified in 7 patients. Out of 76 apparently homozygous subjects, RP-PCR allowed us to detect 56 expansions specific to DM2, and out of 378 ataxia patients, a large allele of the ATXN8OS gene (SCA8) was found in 25 subjects. Conclusions Here, for the first time, we report detection of large expansions in EPM1 and SCA8 patients. This RP-PCR assay is high throughput, reproducible and sensitive enough to be successfully used for diagnostic purposes.Wstęp i cel pracy Oparta na konwencjonalnej reakcji łańcuchowej polimerazy (PCR) diagnostyka molekularna chorób związanych z niestabilnymi sekwencjami powtórzonymi bywa niewystarczająca do wykrycia ogromnych ekspansji, wówczas konieczne jest stosowanie hybrydyzacji. W celu usprawnienia analizy molekularnej trzech chorób wywoływanych mutacjami dynamicznymi: postępującej padaczki mioklonicznej (EPM1), dystrofii miotonicznej typu 2 (DM2) i ataksji rdzeniowo-móżdżkowej typu 8 (SCA8) zaadaptowano technikę RP-PCR (repeat primed PCR), którą uprzednio opracowano dla chorób powodowanych ekspansjami sekwencji trójnukleo-tydowych. Materiał i metody Oprócz standardowej reakcji PCR, w której uzyskiwano allele w zakresie możliwym do amplifikacji, celem detekcji większych ekspansji stosowano RP-PCR. Elektroforetyczny rozdział produktów PCR na automatycznym sekwenatorze umożliwiał analizę alleli z zakresu prawidłowego oraz patogennego, które zawierały dwunasto-nukleotyd (C4GC4GCG)n w EPM1 u 44 osób badanych, czteronukleotyd (CCTG)n w DM2 u 76 osób i trójnukleotyd (CTG)n w SCA8 u 378 pacjentów. Wyniki: Zastosowany protokół diagnostyczny oparty na konwencjonalnej reakcji PCR i RP-PCR pozwolił na szybkie otrzymanie wiarygodnych wyników testu genetycznego w kierunku wyżej wymienionych chorób. Spośród 44 osób poddanych analizie w kierunku EPM1 wyodrębniono 7 przypadków patogennej ekspansji. Wśród 76 osób z dystrofią mio-toniczną, których wyniki po standardowej reakcji PCR wskazywały na genotyp prawidłowy (homozygoty) zastosowanie reakcji RP-PCR umożliwiło identyfikację 56 osób z ekspansją powodującą DM2. Analogicznie w grupie 378 pacjentów z ataksją, w 25 przypadkach wykryto patogenne allele genu ATXN8OS (SCA8). Wnioski W pracy przedstawiono po raz pierwszy zastosowanie RP-PCR w diagnostyce molekularnej do wykrywania dużych ekspansji u pacjentów z podejrzeniem EPM1 i SCA8. Ze względu na wysoką wydajność, powtarzalność i czułość techniki RP-PCR może być stosowana do celów diagnostycznych

Występowanie ataksji rdzeniowo-móżdżkowych spowodowanych mutacjami dynamicznymi u pacjentów w populacji polskiej

Background and purpose Autosomal dominant spinocerebellar ataxias (SCAs) belong to a group of neurodegenerative disorders usually of adult age at onset. Predominant clinical features are progressive ataxia, dysarthria, as well as pyramidal signs and polyneuropathy. Molecular analysis allows particular types of SCA to be distinguished. Genetic tests are applied in 10 types of SCA resulting from dynamic mutations: SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA10, SCA12, SCA17 and DRPLA. Material and methods DNA samples from 1598 patients with ataxia symptoms were analysed to establish the number of CAG/CTG repeats in respective genes excluding SCA10. Results We diagnosed 224 cases of SCA1 (120 families) and 49 cases of SCA2 (23 families). Moreover, presymptomatic testing was done in 85 individuals from SCA1 families and for 21 cases from SCA2 families. An increased number of CTG repeats in the SCA8 gene was observed in 14 families and in 3 families a rare type of SCA, SCA17, was detected. Conclusions Our data suggest that frequencies of some types of SCA in Poland are different from those in other European countries, with irregular distribution within the country. The most frequent types are SCA1 and SCA2. A striking feature of the Polish population is the lack of SCA3 – the most frequent type in Western Europe.Wstęp i cel pracy Ataksje rdzeniowo-móżdżkowe (SCA) o dziedziczeniu autosomalnym dominującym należą do grupy chorób zwyrodnieniowych układu nerwowego, zazwyczaj o późnym wieku zachorowania. W obrazie klinicznym dominują postępująca ataksja i dyzartria, obserwuje się również objawy piramidowe i polineuropatię. Badania molekularne umożliwiają obecnie rozróżnienie poszczególnych typów SCA. Wykonuje się je w przypadkach 10 typów SCA, u podłoża których leżą mutacje dynamiczne zlokalizowane w odpowiednich genach: SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA10, SCA12, SCA17 i DRPLA. Materiał i metody Materiał do badań molekularnych stanowiły próbki DNA od 1598 pacjentów, u których obserwowano objawy ataksji. Analiza genetyczna polegała na ustaleniu liczby powtórzeń CAG/CTG we wszystkich wyżej wymienionych genach z wyjątkiem SCA10. Wyniki Stwierdzono 224 przypadki SCA1 w 120 rodzinach oraz 49 przypadków SCA2 (23 rodziny). Wykonano ponadto przedkliniczne molekularne badania u 85 osób z rodzin z SCA1 i u 21 osób z rodzin z SCA2. W 14 rodzinach stwierdzono nieprawidłową liczbę powtórzeń CTG w genie SCA8, a w 3 rodzinach bardzo rzadką postać ataksji – SCA17. Wnioski Uzyskane dane wskazują, że częstość występowania poszczególnych typów SCA w Polsce jest odmienna niż w innych krajach Europy, a ich rozmieszczenie na terenie kraju nierównomierne. Najczęściej występują SCA1 i SCA2, podczas gdy brak jest SCA3 – najbardziej rozpowszechnionego typu SCA w Europie Zachodniej

Value of short exercise and short exercise with cooling tests in diagnosis of recessive form of myotonia congenita (Becker disease) — are sex differences important?

Introduction: In myotonia congenita (MC), activation with exercise or cooling can induce transient changes in compound motor action potential (CMAP) parameters, thus providing a guide to genetic analysis.Material and methods: We performed the short exercise test (SET) and the short exercise test with cooling (SETC) in 30 patients with genetically confirmed Becker disease (BMC) to estimate their utility in the diagnosis of BMC.Results: Although we observed a significant decrease in CMAP amplitude immediately after maximal voluntary effort in both tests in the whole BMC group, in men this decline was significantly smaller than in women, especially in SET.Clinical implications/future directions: In men with a clinical suspicion of BMC, a small decrease in CMAP amplitude in SET together with a typical decline in SETC does not exclude the diagnosis of BMC. Our results show a sex-specific difference in chloride channel function in BMC, which needs further investigation