Določanje prisotnosti ekspanzije v genu RFC1 pri bolnikih s Parkinsonovo boleznijo

Šušmelj, Lara (avtor), Kovanda, Anja (mentor)

Parkinsonova bolezen (PB) je pogosta napredujoča nevrodegenerativna bolezen, za katero so značilni tremor v mirovanju, bradikinezija in mišično rigidnost, pa tudi nekatere nemotorične značilnosti. Sindrom cerebelarne ataksije, nevropatije in vestibularne arefleksije (CANVAS) je redkejša vrsta ataksije s poznim nastopom, ki ima nekatere simptome, ki se prekrivajo s Parkinsonovo boleznijo, kot so težave z gibanjem, težave z ravnotežjem ter težave z zaznavo. Pri Parkinsonovi bolezni lahko genetske vzroke določimo pri približno 10 % bolnikov, medtem ko je bil genetski vzrok za CANVAS ugotovljen pred nedavnim. Dokazano je bilo, da CANVAS povzročajo homozigotne patogene (AAGGG)n ekspanzije v genu RFC1. Patogena razširitev se od referenčnega alela (AAAAG)11 razlikuje po sekvenci in dolžini. Bolezen se razvije v primeru ekspanzij (AAGGG)exp ali (AAAGG)exp v velikem številu ponovitev (od 400 ponovitev) na obeh alelih. Leta 2022 so prvič ugotovili, da so lahko patogene ekspanzije povezane s CANVAS prisotne tudi pri bolnikih s klinično diagnozo Parkinsonove bolezni. Ker je odstotek genetsko pojasnjene Parkinsonove bolezni nizek, CANVAS pa do nedavnega ni bila dobro poznana bolezen, obstaja možnost da so med bolniki z Parkinsonovo boleznijo tudi taki, ki imajo CANVAS, kar v Sloveniji do sedaj še ni bilo preverjeno. Naš cilj je bil določiti morebitno prisotnost za CANVAS značilnih patogenih ekspanzij v kohorti bolnikov s Parkinsonovo boleznijo. Testiranje smo izvedli z uporabo dvostopenjske fluorescenčne verižne reakcije s polimerazo (PCR), ki temelji na začetnem izključevanju dolgih ekspanzij v prvi stopnji, in na potrditvi patogene sekvence dolgih ekspanzij na drugi stopnji, z detekcijo s fragmentno analizo. V raziskavi smo v kohorti Parkinsonovih bolnikih našli dva s homozigotnimi patogenimi ekspanzijami v genu RFC1. Odstotek tovrstnih bolnikov je v Sloveniji podoben tistemu, ki ga poročajo v drugih evropskih državah

• Jezik: Slovenski jezik
• Ključne besede: Parkinsonova bolezen, CANVAS, PCR, TP-PCR, ekspanzije
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: BF - Biotehniška fakulteta
• Leto izida: 2024
• PID: 20.500.12556/RUL-165882
• COBISS.SI-ID: 218994179
• Datum objave v RUL: 12.12.2024

ŠUŠMELJ, Lara, 2024, Določanje prisotnosti ekspanzije v genu RFC1 pri bolnikih s Parkinsonovo boleznijo [na spletu]. Magistrsko delo. [Dostopano 21 april 2025]. Pridobljeno s: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=slv&id=165882

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Characterization of exspansions in RFC1 gene in patients with Parkinson's disease

Izvleček

Parkinson's disease is a common, progressive neurodegenerative disease, with typical tremor, bradykinesia and muscle rigidity, and non-motor symptoms. The cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is a rarer type of late-onset ataxia, some of whose symptoms, such as movement, balance and sensory problems, may overlap with Parkinson’s disease. While genetic causes can be established in approximately 10 % of patients with Parkinson’s disease, the genetic cause of CANVAS has been identified only recently. CANVAS is now understood to be caused by biallelic pathogenic (AAGGG)n repeat expansions in the RFC1 gene. The pathogenic expansion differs in nucleotide sequence and size from the reference allele (AAAAG)11. Only large biallelic expansion with the (AAGGG)exp or (AAAGG)exp (over 400 repeats) sequence are considered to be pathogenic. In 2022, it was shown for the first time that pathogenic expansions associated with CANVAS may also be present in patients clinically diagnosed as Parkinson's patients. Because the percent of Parkinson’s disease patients explained by genetic testing is low, while CANVAS was relatively unknown until recently, the possibility exists that there may be CANVAS patients among the undiagnosed Parkinson’s disease patients, a hypothesis that has not yet been tested in Slovenia. Our aim was to determine the possible presence of CANVAS-specific pathogenic expansions in a cohort of Parkinson's disease patients. We performed CANVAS testing by using a two-step fluorescent polymerase chain reaction (PCR), based on the initial exclusion of long expansions in CANVAS, and a second stage confirmation of long pathogenic expansions, with the detection based on fragment analysis. By applying this method, we found two patients with homozygous pathogenic expansions in RFC1 in our cohort of patients with Parkinson’s disease. The percent of such patients in Slovenia is similar to that reported in other European populations.

• Ključne besede: Parkinson disease, CANVAS, PCR, RP-PCR, expansions