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Opis: Purpose: About 10-15% of all pregnancies terminate as spontaneous miscarriages. In the first trimester, 50% of spontaneous miscarriages are the result of chromosomal aberrations, mostly chromosomal aneuploidies. Cytogenetic analyses are used to confirm aneuploidy in failed pregnancies. Culture failure or poor quality chromosomes are often problems in those cases. In such situations, methods that are independent of tissue culture areused, and we employed multiplex ligation-dependent probe amplification (MLPA). We determined if MLPA is an appropriate and compatible method compared with classical cytogenetic analyses on fetal tissues. Methods: All fetal samples received from spontaneous abortions were cultured, karyotyped (if possible) and genomic DNA extracted. MLPA analyses were undertaken using subtelomeric probe kits. Additionally, comparative genomic hybridization (CGH) was used to confirm aneuploidy detected by MLPA in cases of failed culture growth. Results: MLPA analyses confirmed an unbalanced chromosome abnormality identified by cytogenetic analyses in all cases in which tissue culture was successful, and provided data in cases of failed culture growth. Several common numeric chromosome aberrations were detected, as well as rare trisomies and other unbalanced chromosome rearrangements. Conclusions: MLPA analyses can provide information about the karyotype of a DNA sample if cytogenetic analyses are not possible because of a lack of viable cells or if only a small amount of genomic DNA is available. These data indicate that MLPA may also be a very useful method for early prenatal aneuploidy screening.
Ključne besede: pomnoževanje od ligacije odvisnih prob, številčne kromosomske preureditve, kariotip
Objavljeno v DKUM: 12.04.2024; Ogledov: 230; Prenosov: 10
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Opis: The objective of this study was to analyze the methylenetetrahydrofolate reductases (MTHFRs) C677T and A1298C genotype distributions in couples with unexplained fertility problems (UFP) and healthy controls, and to analyze the genotype and haplotype distribution in spontaneously aborted embryonic tissues (SAET) using allele specific polymerase chain reaction (PCR) in 200 probands with UFP, 353 samples of SAET and 222 healthy controls. The analysis revealed a significant overall representation of the 677T allele in male probands from couples with UFP (p = 0.036). The combined genotype distribution for both MTHFR polymorphisms was also significantly altered (χ2 21.73, p <0.001) although female probands made no contribution (c2 1.33, p = 0.72). The overall representation of the 677T allele was more pronounced in SAET (0.5 vs. 0.351 in controls, p <0.001) regardless of the karyotype status (aneuploidy vs. normal karyotype). In addition, the frequencies of the CA and CC haplotypes were significantly lower than in the control group (p = 0.021 and p = 0.001, respectively), whereas the frequency of the TC haplotype was significantly higher than in controls (p <0.0001). The presented findings indicate that only male probands contribute to the association of MTHFR mutations with fertility problems in grown adults and demonstrate a high prevalence of mutated MTHFR genotypes in SAET.
Ključne besede: methylenetetrahydrofolate reductase (MTHFR), genotype, haplotype, infertility, miscarriage
Objavljeno v DKUM: 30.03.2017; Ogledov: 1469; Prenosov: 364
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Opis: Izhodišča. Kromosomske napake so lahko eden od vzrokov za idiopatsko mentalno retardacijo (IMR) in dismorfologijo. V prispevku poročamo o vpeljavi simultane metode fluorescenčne hibridizacije "in situ" (FISH) za odkrivanje subtelomernih kromosomskih preureditev. Ugotavljamo, da je metoda lahko uporabna za rutinsko citogenetsko diagnostiko IMR, kongenitalnih anomalij in razreševanje kompleksnejših kariotipov. Pilotsko študijo smo izvedli pri 56 bolnikih, otrocih iz severovzhodne Slovenije, ki so bili napoteni v citogenetski laboratorij z diagnozo mentalne retardacije in/ali displastičnih znakov. Metode. Vsem bolnikom smo odvzeli 5 ml periferne krvi in jih kariotipizirali. Za odkrivanje kromosomskih sprememb v terminalnih regijah kromosomov smo uporabili metodo FISH z uporabo kompleta Multiprobe T-System (Cytocell) ter posamezne lokusno specifične DNK sonde. Rezultati. Subtelomerne spremembe smo našli pri 5,4% bolnikov. Od tega so pri 3,6% bolnikov subtelomerne aberacije nastale "de novo". 2q subtelomerna delecija: del(2)(qtel), ki smo jo našli pri dveh bolnikih, pa se je izkazala kot dedovani polimorfizem. Subtelomerne aberacije smo potrdili pri enem pacientu z delecijo terminalnega dela kratkega kraka kromosoma X: del(X)(ptel) in pri drugem z delecijo terminalnega dela dolgega kraka 13: del(13)(qtel) in parcialno trisomijo dela dolgega kraka kromosoma 10. Zaključki. S prikazano študijo ugotavljamo, da je metoda FISH z multiplimi subtelomernimi DNK-sondami uporabno diagnostično orodje za odkrivanje enega od vzrokov IMR pri bolnikih z displastičnimi znaki ali brez teh znakov s sicer normalnim kariotipom.
Objavljeno v DKUM: 21.12.2015; Ogledov: 2356; Prenosov: 91
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Opis: Purpose: Comparative genomic hybridization (CGH) is a molecular- cytogenetic technique used to identify chromosomal imbalances throughout a genome. Due to its complexity, the use of CGH as a regular diagnostic technique is limited to only a few diagnostic laboratories. In this study, we evaluated the potential applications of CGH as a diagnostic method in different post-natal clinical samples. Methods: Ten patients were recruited with submicroscopic chromosomal abnormalities ranging in size from 3.9 to 37 Mb. For the purpose of confirmation, CGH was applied to five cases where molecular karyotyping with MLPA was previously utilized to detect chromosome aneuploidy. To date, CGH was largely used for the identification of the complex karyotype in haematological malignancies. Results: In eight cases of haematological malignancies, we were able to resolve complex karyotypes with CGH. Utilizing CGH as a diagnostic tool, we detected chromosomal imbalances larger than 8 Mb. In addition, we confirmed all chromosomal aneuploidies that were previously detected with MLPA from embryonic tissues obtained from aborted fetuses. In this tissue, the cells were not mitotically active, and therefore, were inappropriate for the conventional cytogenetics. Conclusion: Because CGH is technically demanding and time consuming, this technique is likely to be inappropriate for screening purposes. However, we found that CGH may be very useful in sporadic cases, where the sample material is not mitotically active or in cases with complex karyotypes. Therefore, our results confirmed that CGH may be useful in laboratories that are unable to use micro-array CGH for economic reasons.
Ključne besede: primerjalna genomska hibridizacija, medicinska genetika, diagnostična metoda
Objavljeno v DKUM: 10.07.2015; Ogledov: 1647; Prenosov: 41
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