Cieľ: Cieľom našej práce bolo identifikovať kauzatívne germinálne mutácie u suspektných NF1 pacientov za účelom diferenciálnej diagnostiky a zozbieranie čo najväčšieho súboru pacientov pre prípadné genotypovo-fenotypové korelácie. Súbor a metodika: Náš súbor pozostával zo 107 nezávislych pacientov zo Slovenska, ktorý boli v období rokov 2008-2013 klinickými genetikmi posúdení ako suspektní pre NF1. Na identifikáciu mutácií bolo použité sekvenovanie cDNA NF1 génu, ktoré nám umožnilo úspešnú identifikáciu zostrihových mutácií, ako aj MLPA analýza umožňujúca identifikáciu rozsiahlejších delécií v géne. Výsledky: V súbore 94 nepríbuzných slovenských pacientov, ktorí spĺňali základné diagnostické kritériá pre neurofibromatózu, sme za použitia našich metód identifikovali germinálne mutácie v NF1 géne u 83 z nich (88,3 %). Zaznamenali sme vysoký podiel mutácií, ktoré boli zatiaľ identifikované len v slovenskej populácii (41/83, 49,4 %), a u 27/42 testovaných rodinách sme potvrdili mutáciu de novo (64,3 %). Genotypovo-fenotypové korelácie odhalili zvýšený výskyt očných gliómov u pacientov s mutáciou na 5’ konci NF1 génu. Závery: Kombinácia cDNA analýzy a MLPA je efektívnou pre identifikáciu mutácií v NF1 géne. Na základe tejto diagnostickej metódy sme odhalili aj často nesprávne klasifikované netypické zostrihové mutácie. Naše výsledky využili klinickí genetici pri diferenciálnej diagnostike ochorenia, hlavne v sporných prípadoch. Kľúčová slová: NF1 gén – kauzatívna germinálna mutácia – RNA zostrih – genotypovo-fenotypové korelácie – de novo mutácie –diferenciálna diagnostika, Aim: The aim of our study was to identify causative germline mutation in suspected NF1 patients, in order to help differential diagnostics, as well as to collect as large as possible group of patients for a possible genotype-phenotype correlations. Material and methods: Our set of patients consisted of 107 Slovak patients, recruited between 2008 and 2013, who were considered for a diagnosis NF1 by clinical genetics. In order to identify mutations, we employed NF1 cDNA sequencing that enabled us to also detect splicing mutations, as well as MLPA analysis that enables identification of larger deletions. Results: By employing the selected methods in our set of 94 unrelated Slovak patients who fulfilled the basic NF1 diagnostic criteria, we uncovered germline mutations in the NF1gene in 83 of them (88.3%). We observed a high proportion of mutations identified in Slovak population only so far (41/83, 49.4%), and we confirmed de novo mutation in 27/42 tested families (64.3%). Genotype-phenotype correlations revealed an increased incidence of optic pathway glioma in patients with a mutation in the 5´end of the NF1 gene. Conclusion: Combination of cDNA analysis and MLPA provides an effective method for identification of mutations in the NF1 gene. By employing these methods, we were able to also identify frequently incorrectly classified atypical splicing mutations. Clinical geneticists used our results in the differential diagnosis of the disease, especially in contested cases. Key words: NF1 gene – causative germline mutation – RNA splicing – genotype-phenotype correlation – de novo mutations –differential diagnostics The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for biomedical papers., and M. Némethová, A. Bolčeková, S. Požgayová, D. Ilenčíková, A. Hlavatá, R. Kádaši, L. Kovácz, A. Zaťková
Dideoxynucleotide DNA sequencing is one of the principal procedures in molecular biology. Loss of an initial part of nucleotides behind the 3' end of the sequencing primer limits the readability of sequenced amplicons. We present a method which extends the readability by using sequencing primers modified by polyadenylated tails attached to their 5' ends. Performing a polymerase chain reaction, we amplified eight amplicons of six human genes (AMELX, APOE, HFE, MBL2, SERPINA1 and TGFB1) ranging from 106 bp to 680 bp. Polyadenylation of the sequencing primers minimized the loss of bases in all amplicons. Complete sequences of shorter products (AMELX 106 bp, SERPINA1 121 bp, HFE 208 bp, APOE 244 bp, MBL2 317 bp) were obtained. In addition, in the case of TGFB1 products (366 bp, 432 bp, and 680 bp, respectively), the lengths of sequencing readings were significantly longer if adenylated primers were used. Thus, single strand dideoxynucleotide sequencing with adenylated primers enables complete or near complete readability of short PCR amplicons. and M. Beránek, M. Drastíková, J. Petera