INTERSTITIAL 14q31.3-q32.13 DELETION: THE ROLE OF MOLECULAR KARYOTYPING IN CLARIFYING THE ETIOLOGY OF DEVELOPMENTAL DELAY

Aim: With the exception of ring chromosome 14 or translocations, interstitial deletions of the long arm of chromosome 14 are very rare. All patients with these deletions share common phenotypic characteristics, primarily mild dysmorphia and developmental delay. Molecular karyotyping (array CGH) enabled the precise breakpoint determination and improved the analysis of genotype-phenotype correlations. Case presentation: In a 7-year-old girl, array CGH was performed due to developmental delay. The array CGH study showed 8.3Mb de novo interstitial deletion of the 14q31.3–q32.13 region. Conclusions: Comparison of our patient´s phenotype with previously reported chromosome 14q interstitial deletion cases confirmed the presence of common clinical features and highlights the utility of array CGH as a diagnostic tool in clarifying the developmental delay etiology

Rapid Prenatal Diagnosis of Numerical Aberrations of Chromosome 21 and 18 by PCR-STR Method

In this study we reported the results for the first time of applying Polymerase Chain Reaction-Short Tandem Repeats (PCR-STR) method in the field of detection of aneuploidies for chromosomes 21 and 18 in Croatians. The aims of the study were: (I) validation of the diagnostic informativeness of 6 STR loci (D18S51, D18S858, D18S535, D21S1435, D21S1411, and D21S1414) in sample of 205 unrelated healthy individuals; (II) evaluation of diagnostic power of the PCR-STR method for those 6 microsatellites; (III) establishment protocol for use STRs as routine method for rapid prenatal detection of trisomy 21 and 18. DNA samples were amplified by fluorescence-based PCR reaction, subjected to electrophoresis in automated laser fluorescence DNA sequencer (ALFexpress). Results of our study were: (I) all 6 tested loci are informative (68–85% of heterozygous individuals); (II) comparison between PCR-STR method and conventional cytogenetics did not revealed any false positive or false negative results; (III) in prenatal screening of 105 samples of uncultured amniotic fluid 6 (5.7%) samples with chromosomal abnormalities were identified

Use of microsatellite loci in prenatal and postnatal diagnosis of aneuploidy and uniparental disomy

Najveći udio svih kromosomopatija u čovjeka čine Downov (trisomija kromosoma 21), Edwardsov (trisomija kromosoma 18) i Patauov (trisomija kromosoma 13) sindrom. Navedena činjenica uputila je na potrebu uvođenja metoda koje bi omogućile brzu dijagnostiku najčešćih numeričkih kromosomskih poremećaja, što je od osobite važnosti u prenatalnoj dijagnostici. Analiza mikrosatelitskih lokusa ili lokusa STR primjenom metode PCR-STR omogućila je brzu dijagnostiku najčešćih aneuploidija u vremenskom razdoblju od jednog do tri dana. Prednost analize lokusa STR u prenatalnoj i postnatalnoj dijagnostici očituje se i u mogućnosti utvrđivanja podrijetla kromosoma u dijagnostici uniparentne disomije. U KBC-u Zagreb brza prenatalna i postnatalna dijagnostika aneuploidija i uniparentne disomije provedena je primjenom analize mikrosatelitskih lokusa kromosoma 7, 11, 13, 14, 15, 18, 21, X i Y. Cilj rada je prikazati dijagnostičku vrijednost primijenjenih mikrosatelitskih lokusa na navedenim kromosomima. Prenatalnim pretraživanjem 2072 uzorka plodovih voda kod njih 55 (2,65%) otkrivena je promjena u broju kromosoma. Očekivano, u najvećem broju uzoraka (n=35) otkrivena je trisomija kromosoma 21. U uzorku od 54-ero ispitanika sa sumnjom na uniparentnu disomiju kod njih 13-ero nađena je uniparentna disomija kromosoma 15 (UPD15). Rezultati metode PCR-STR bili su u skladu s rezultatima metode klasične citogenetike. Zaključno možemo reći da je kombinacija mikrosatelitskih lokusa koju primjenjujemo dostatno informativna za uspješno određivanje aneuploidije kromosoma 13, 18, 21, X i Y i uniparentne disomije kromosoma 7,11,14 i 15.The largest proportion of all chromosomal anomalies in humans are syndromes Down (trisomy of chromosome 21), Edwards (trisomy of chromosome 18) and Patau (trisomy of chromosome 13). This fact has revealed the need to introduce methods that would allow rapid diagnosis of the most common numerical chromosomal abnormalities, which is of special importance in prenatal diagnosis. Analysis of the microsatellite or STR locus with the PCR-STR method has given us the possibility of fast diagnosis of the most frequent aneuploidies within one to three days. The advantage of the analysis of STR loci in prenatal and postnatal diagnosis lies in the ability to determine the origin of chromosomes in the diagnosis of uniparental disomy. At the Zagreb University Hospital Centre, rapid prenatal and postnatal diagnosis of aneuploidy and uniparental disomy was performed using analysis of the microsatellite loci of chromosomes 7, 11, 13, 14, 15, 18, 21, X and Y. The purpose of the work was to show diagnostic value of the microsatellite loci on the above listed chromosomes. On prenatal screening of 2072 amniotic fl uid samples, 55 (2.65%) showed change in the number of chromosomes. As expected, the largest number of samples (n=35) showed trisomy of chromosome 21. Uniparental disomy of chromosome 15 (UPD15) was demonstrated in 13 of 54 subjects with suspicion of uniparental disomy. The results of the PCR-STR method were in accordance with the results of conventional cytogenetics. In conclusion, the combination of STR loci that we use is considered good enough to determine aneuploidy of chromosomes 13, 18, 21, X and Y, and uniparental disomy of chromosomes 7, 11, 14 and 15

Pallister Killian Syndrome: Unusual Significant Postnatal Overgrowth in a Girl with otherwise Typical Presentation

Pallister Killian syndrome (PKS) is a rare genetic disorder caused by tetrasomy of the short arm of chromosome 12, revealed usually in mosaic distribution of an extra i(12)(p10) chromosome in fibroblasts. The syndrome presents with a recognizable pattern of findings including pigmentary skin changes, coarse face, high forehead, sparse anterior scalp hair, hypertelorism, seizures and progressive psychomotor developmental delay. It was first described independently by Pallister in 1977 and by Killian and Teschler-Nikola in 19811,2. We report a case of 21 month old girl with PKS and significant overgrowth. Cytogenetic analysis was performed using the GTG banding technique. The karyotype of cultured lymphocytes was normal. The karyotype from skin fibroblasts was established as mosaic tetrasomy of 12p 47,XX,+i(12) (p10)/46,XX. The origin of the extra marker chromosome was determinated by fluorescence in situ hybridization with chromosome 12 specific DNA probes confirming that supernumerary marker is chromosome i(12p) in 68% of cells. Despite the excessive postnatal growth we found low serum growth hormone levels and reduced response to pharmacological stimulation test. This is also the first report of a postnatal patient in our country

Povezanost polimorfizma gena za protein visoke pokretljivosti iz skupine 1 (rs41369348) i imunoglobulin A vaskulitisa kod djece

Immunoglobulin A vasculitis (IgAV) or Henoch-Schönlein purpura is the most prevalent systemic small vessel vasculitis in childhood. High mobility group box 1 protein (HMBG1) is a pleiotropic cytokine that functions as a pro-inflammatory signal, important for the activation of antigen-presenting cells and propagation of inflammation. HMGB1 is implicated in the pathophysiology of a variety of inflammatory diseases. The aim of this study was to investigate the role of single nucleotide polymorphism rs41369348 for HMGB1 gene in the susceptibility and clinical features of patients meeting the classification criteria for IgAV. DNA was extracted from blood cells of 76 children with IgAV and 150 age-matched healthy controls. Clinical data and laboratory parameters were collected for all IgAV patients. Although there was a higher frequency of heterozygous A/delA genotype of this gene polymorphism in IgAV group as compared with control group, no genotype difference was observed between these two groups. No statistically significant genotype differences were disclosed when patients with different IgAV clinical features were compared. In conclusion, in this study, polymorphism rs41369348 for HMGB1 was not associated with increased susceptibility to childhood IgAV, its severity or different clinical manifestations.Imunoglobulin A vaskulitis (IgAV) ili Henoch-Schönleinova purpura najčešći je sistemski vaskulitis malih krvnih žila u dječjoj dobi. Protein visoke pokretljivosti iz skupine 1 (high mobility group box-1 protein, HMGB1) pleiotropni je citokin koji djeluje kao proupalni signal, važan za aktiviranje antigen prezentirajućih stanica i širenje upale. HMGB1 ima ulogu u patofiziologiji različitih upalnih bolesti. Cilj ovog rada bio je istražiti povezanost polimorfizma gena (SNP)-rs41369348 za HMGB1 s predispozicijom za IgAV i kliničkom slikom bolesnika koji ispunjavaju kriterije za IgAV. DNA je ektstrahirana iz krvnih stanica 76 djece s IgAV-om i 150 zdrave kontrolne djece koja se po dobi nisu razlikovala. Klinički podaci i laboratorijski parametri prikupljeni su za sve bolesnike s IgAV-om. Iako postoji veća učestalost heterozigotnog genotipa A/ delA ovog genskog polimorfizma u skupini s IgAV-om u odnosu na kontrolnu skupinu, nije uočena genotipska razlika između navedenih skupina. Nije nađena statistički značajna genotipska razlika između bolesnika s različitom kliničkom slikom IgAV-a. Zaključno, u ovom istraživanju nije nađena povezanost polimorfizma rs41369348 za HMGB1 s predispozicijom za nastanak IgAV-a u djece, kao niti s težinom bolesti ili njezinim različitim kliničkim manifestacijama