Detection of mutations in the CYP21A2 gene

The objective of this study was to compare the CYP 21A2 genetic profiles of couples with unexplained fertility problems (UFP) with genetic profiles of healthy controls (HCs). Furthermore, we analyzed associations between mutations in the CYP21A2 gene and various clinical and laboratory parameters. Allele-specific polymerase chain reaction (PCR) was used in 638 probands with UFP and 200 HCs. Statistic analysis with χ2 was used to study the association of mutations with infertility. The effect of mutations on particular clinical and laboratory parameters was assessed with the analysis of variance (ANOVA) test. With regard to the CYP21A2 gene, 0.6% of probands with UFP and 0.5% of HCs were positive for the c.290-13A/C>G mutation0.6% of probands with UFP and 1.5% of HCs were positive for the p.I172N mutationthere were no probands with UFP positive for the p.P30L mutation, whereas 0.5% of HCs wereand 0.2% of probands with UFP and 0.5% of HCs were found to have the p.V281L mutation. We found a significant association between c.290-13A/C>G mutation and the frequency of significant hormone deviations (χ2 = 6.997, p = 0.008). Similar association was also observed between the c.29013A/C>G mutation and the frequency of polycystic ovary syndrome (PCOS) (χ2 = 16.775, p = 0.000). Our findings indicate that no significant difference in the prevalence of CYP 21A2 mutations can be found in probands with UFP when compared with HCs without infertility history. The results also imply the significant association of the c.290-13A/ C>G mutation in the CYP21A2 gene, not only with the frequency of PCOS, but also with the frequency of significant hormone deviations

Ugotavljanje VKORC1 polimorfizma

Purpose: The VKORC1 polymorphism is an important genetic factor affecting warfarin dose requirement. Patients require different warfarin doses in order to achieve the target therapeutic anticoagulation. The aim of our study was to determine the frequency of single nucleotide polymorphisms (SNP) in the VKORC1gene in the general population, using a simple, rapid, and economical method. Methods: For genotyping, the restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) amplified DNA was used and compared to allele specific polymerase chain reaction. We genotyped 441 DNA samples obtained from the healthy general population in North Eastern Slovenia. Genotypes for the tested group were evaluated to determine whether the population followed the Hardy Weinberg equilibrium. The genotypes and allele frequencies were calculated. Results: The results obtained using the allele specific polymerase chain reaction were consistent with those obtained using the PCR + RFLP method. The G allele frequency (0.62) was higher than the A allele frequency (0.38) in the general population from North Eastern Slovenia. Conclusions: The PCR+RFLP method involved additional manipulation of the PCR products at the expense of analysis time, consumption of reagents and equipment. The allele specific polymerase chain reaction was a simple and rapid method for the detection of SNP in theVKORC1 gene, and is available in any laboratory with the minimum of equipment and reagents required.Namen: VKORC1 polimorfizem je pomemben genetski dejavnik, ki vpliva na zahtevan odmerek varfarina pri bolnikih, ki potrebujejo različne odmerke varfarina za doseganje antikoagulacijskega terapevtskega učinka. Cilj naše raziskave je bil na vzorcu splošne populacije ugotoviti frekvenco enonukleotidnega polimorfizma (SNP) v VKORC1 genu na preprost, hiter in ekonomičen način. Metode: Za genotipizacijo smo uporabili metodo verižne reakcije s polimerazo oz. polimorfizem dolžin restrikcijskih fragmentov (PCR/RFLP), ki smo jo primerjali z metodo alelno specifične verižne reakcije s polimerazo. Genotipizirali smo 441 vzorcev genomske DNA preiskovancev iz severovzhodne Slovenije. Ocenili smo, ali je izbrana skupina v Hardy Weinbergovem ravnovesju, ter izračunali posamezne genotipe in frekvenco alelov. Rezultati: Rezultati, pridobljeni z alelno specifično verižno reakcijo s polimerazo, so se popolnoma ujemali z rezultati, pridobljenimi z metodo PCR/RFLP. Frekvenca alela G (0,62) je višja kot frekvenca alela A (0,38) v testirani skupini iz severovzhodne Slovenije. Zaključek: Izkazalo se je, da PCR/RFLP metoda vključuje dodatne korake na račun časa analize, porabe reagentov in opreme. Na podlagi rezultatov zaključujemo, da alelno specifična verižna reakcija s polimerazo omogoča odkrivanje SNP v VKORC1 genu na bolj enostaven, hitrejši in cenovno bolj sprejemljiv način

Detection of mutations in the CYP21A2 gene: genotype-phenotype correlation in Slovenian couples with conceiving problems

The objective of this study was to compare the CYP 21A2 genetic profiles of couples with unexplained fertility problems (UFP) with genetic profiles of healthy controls (HCs). Furthermore, we analyzed associations between mutations in the CYP21A2 gene and various clinical and laboratory parameters. Allele-specific polymerase chain reaction (PCR) was used in 638 probands with UFP and 200 HCs. Statistic analysis with χ2 was used to study the association of mutations with infertility. The effect of mutations on particular clinical and laboratory parameters was assessed with the analysis of variance (ANOVA) test. With regard to the CYP21A2 gene, 0.6% of probands with UFP and 0.5% of HCs were positive for the c.290-13A/C>G mutation; 0.6% of probands with UFP and 1.5% of HCs were positive for the p.I172N mutation; there were no probands with UFP positive for the p.P30L mutation, whereas 0.5% of HCs were; and 0.2% of probands with UFP and 0.5% of HCs were found to have the p.V281L mutation. We found a significant association between c.290-13A/C>G mutation and the frequency of significant hormone deviations (χ2 = 6.997, p = 0.008). Similar association was also observed between the c.29013A/C>G mutation and the frequency of polycystic ovary syndrome (PCOS) (χ2 = 16.775, p = 0.000). Our findings indicate that no significant difference in the prevalence of CYP 21A2 mutations can be found in probands with UFP when compared with HCs without infertility history. The results also imply the significant association of the c.290-13A/ C>G mutation in the CYP21A2 gene, not only with the frequency of PCOS, but also with the frequency of significant hormone deviations

Določanje anevploidij z metodo pomnoževanja od ligacije odvisnih prob v fetalnih tkivih splavkov

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.Namen: Spontani splavi se pojavljajo v približno 10-15% prepoznavnih nosečnosti. V prvem trimesečju je približno 50% splavov posledica kromosomskih napak, v večini primerov so to kromosomske anevploidije. Klasična metoda določanja anevploidij je citogenetska analiza. Citogenetska analiza zgodnjih spontanih splavov je težavna zaradi pogoste odsotnosti celične rasti ali slabe kvalitete kromosomov. V teh primerih se poslužujemo drugih metod, neodvisnih od rasti celične kulture. V študiji smo uporabili metodo pomnoževanja od ligacije odvisnih prob (MLPA). V primerjavi s klasično citogenetsko analizo smo na vzorcu embrionalnih tkiv potrdili ustreznost in kompatibilnost metode. Metode: Vsi vzorci embrionalnih tkiv po spontanih splavih so bili kultivirani, kariotipizirani, prav tako je bila izolirana genomska DNA. Za MLPA analizo smo uporabili komercialne komplete s subtelomerno specifičnimi DNA sondami. V primeru odsotnosti celične rasti so bile anevploidije ugotovljene z MLPA analizo, potrjene s primerjalno genomsko hibridizacijo (PGH). Rezultati: MLPA analiza je potrdila neuravnotežene kromosomske nepravilnosti, ugotovljene s citogenetsko analizo pri vseh vzorcih, kjer je bila uspešna celična rast, in hkrati omogočila analizo v primerih, kjer celična rast ni bila uspešna. Ugotovljene so bile mnoge številčne kromosomske spremembe, redke trisomije in druge neuravnotežene kromosomske preureditve. Zaključek: MLPA analiza omogoča pridobitev informacij o številu kromosomov v primerih, ko citogenetska analiza ni možna zaradi odsotnosti celične rasti ali slabe kvalitete kromosomov. Iz dobljenih rezultatov ugotavljamo, da je MLPA potencialno tudi zelo uporabna metoda za hitro in kvalitetno prenatalno diagnostiko

De novo KMT2D heterozygous frameshift deletion in a newborn with a congenital heart anomaly

Kabuki syndrome (KS) is characterized by typical facial features and patients are also affected by multiple congenital anomalies, of which congenital heart anomalies (CHAs) are present in 28.0 to 80.0%. In approximately 75.0% of patients, the genetic causes of KS are caused by mutation in the KMT2D gene. Although KS is a well-characterized syndrome, reaching the diagnosis in neonates is still challenging. Namely, newborns usually display mild facial features; therefore the diagnosis is mainly based on congenital malformations. In our case, a newborn was referred for next generation sequencing (NGS) testing due to the prenatally observed CHA. After birth, a ventricular septal defect (VSD), vesicoureteral reflux, muscular hypotonia, cleft palate, mild microcephaly, and some dysmorphic features, were noted. The NGS analysis was performed on the proband’s genomic DNA using the TruSight One Sequencing Panel, which enriches exons of 4813 genes with clinical relevance to the disease. After variant calling, NGS data analysis was predominantly focused on rare variants in genes involved in VSD, microcephaly, and muscular hypotonia; features observed predominantly in our proband. With the aforementioned protocol, we were able to determine the previously unreported de novo frameshift deletion in the KMT2D gene resulting in translation termination. Although our proband is a typical representative of KS, his diagnosis was reached only after NGS analysis. Our proband thus represents the importance of genotypephenotype driven NGS analysis in diagnosis of patients with congenital anomalies

The use of comparative genomic hybridization as a diagnostic tool in medical genetics laboratories

Namen: Primerjalna genomska hibridizacija (PGH) je molekularno citogenetska tehnika za identifikacijo kromosomskih neravnovesij po celotnem genomu. Zaradi njene kompleksnosti jo kot rutinsko diagnostično metodo uporablja samo nekaj laboratorijev po svetu. Predstaviti želimo svoje izkušnje pri delu s tehniko PGH in njeno diagnostično uporabnost pri post-natalnih kliničnih vzorcih. Metode: Validacijo PGH tehnike smo opravili na vzorcu 10 preiskovancev z diagnozo nepojasnjena mentalna retardacija in s predhodno določenimi subtelomernimi kromosomskimi spremembami v velikostnem razredu 3,9 do 37 Mbp. Kot potrditveno metodo za določitev kromosomske aneuploidije smo PGH uporabili pri petih vzorcih embrionalnega tkiva po spontanih splavih. Pri enajstih hematoloških onkoloških vzorcih smo PGH uporabili pri razreševanju kompleksno preurejenih kariotipov. Rezultati: S PGH smo našli subtelomerne kromosomske spremembe, večje od 8 Mbp. Z metodo PGH smo potrdili vse z molekularno kariotipizacijo predhodno najdene kromosomske aneuploidije v embrionalnih tkivih po spontanih abortusih, kjer celice niso bile več mitotsko aktivne. Največja uporabnost PGH se je pokazala pri pojasnjevanju kompleksnih kromosomskih preureditev v primerih hematoloških malignih obolenj. Zaključek: Čeprav je PGH tehnično zahtevna in zamudna tehnika in kot taka neprimerna za rutinsko diagnostično delo, je po naših izkušnjah nepogrešljiva v posameznih primerih, v katerih druge genetske analize niso uporabne, npr. pri mitotsko neaktivnem celičnem materialu ali pri kompleksno preurejenih kariotipih. Naše izkušnje in rezultati potrjujejo njeno uporabnost predvsem v tistih genetskih laboratorijih, kjer zaradi ekonomskih razlogov še niso uspeli vpeljati pregledovanja genoma na osnovi t.i. micro-array tehnologije.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