Sanger sequencing of MMR genes in a one-plate system

Simultaneous FLT3, NPM1 and DNMT3A mutations in adult patients with acute myeloid leukemia – case study

Background: Nowadays, cytogenetics and molecular genetics, but not only, are mandatory in acute myeloid leukemia (AML) management, as a consequence of their impact on AML pathogenesis, classification, risk-stratification, prognosis and treatment. Objective: The aim of our study was to present our algorithm for the analysis of copy number changes, aneuploidies and somatic mutations focusing on a rare AML case positive for four somatic mutations. Methods: Cytogenetic analysis, Multiplex Ligationdependent Probe Amplification (MLPA) analysis, somatic mutation analysis (for FLT3 ITD, FLT3 D835, DNMT3A R882 and NPM1 c.863_864ins) by using several PCR techniques and also next-generation sequencing (NGS) analysis were performed. Results: Cytogenetic analysis did not reveal structural or numerical chromosomal anomalies. The patient’s DNA showed no copy number changes or aberrations (CNAs) following the MLPA analysis. By using several molecular technologies we found four mutations: FLT3-ITD, FLT3 D835 (c.2504A>T, D835V), DNMT3A R882C, and NPM1 c.863_864insTCTG. Challenges, benefits, applications and the limitations of each molecular technique used for the investigation of the mentioned mutation, and not only, are also described. Conclusion: All these techniques can be useful in the diagnosis of AML patients, each of them covering the limits of the other technique. New strategies for a positive, fast, accurate and reliable diagnosis are mandatory in cases with AML.

The utility of molecular genetic techniques in craniosynostosis cases associated with intellectual disability

Molecular genetic testing in craniosynostosis leads to the detection of the mutations in the genes encoding fibroblast growth factor receptors (FGFR), providing information about the etiology of the genetic disorder. Muenke syndrome is produced by p.Pro250Arg mutation in FGFR3 gene with evidence of variable expressivity, representing 8% of the syndromic craniosynostoses.

Here, we present the identification of a p.Pro250Arg pathogenic mutation (c.749C>G) in the FGFR3 gene using Multiplex Ligation-dependent Probes Amplification (MLPA) analysis in conjunction with Sanger sequencing in a patient with craniosynostosis and mild intellectual disability. The MLPA analysis detected a reduced signal of the probe, at the site of the c.749C>G mutation, defined by the presence of one allele of C749>G mutation in the FGFR3 gene, exon 7. Sanger sequencing was performed for confirmation and identified heterozygous p.Pro250Arg pathogenic variant (c.749C>G) in exon 7 of the FGFR3.

In conclusion, we assessed the validity and clinical utility of the combined molecular genetic techniques, MLPA analysis, and Sanger sequencing, for craniosynostosis and intellectual disability, improving not only the diagnostic testing but also the genetic counseling and management of the disorder.