👤 Aouina Ammar

Congenital heart defects represent a major global health burden, affecting nearly one million newborns annually. Identifying the underlying genetic causes is essential for improved diagnosis, patient management, and genetic counseling. We conducted a cytogenetic study integrating conventional karyotyping, fluorescence in situ hybridization (FISH), and chromosomal microarray analysis (CMA 44 K) in 20 Tunisian patients presenting syndromic CHDs and referred to our Genetics Department. CMA identified pathogenic copy number variations in four patients. These included an inherited 11 Mb deletion at 9p24.2 together with a 10 Mb duplication of 20pter; a de novo 1.2 Mb deletion at 15q26.2 with an 11 Mb duplication at 2q36.3; a de novo 113 kb deletion at 17q21.32; and a de novo 48 Mb duplication at 8q22. Several CNVs overlapped known deletion/duplication syndromes, some with previously infrequent cardiac involvement. Genotype-phenotype correlations enabled prioritization of CHD relevant genes including DOCK8, HTR2B, KANSL1, ZFPM2, and TRPS1, whose dosage sensitivity and interactions with cardiac developmental pathways may contribute to the observed phenotypes. This study reinforces the clinical utility of CMA in detecting cryptic chromosomal abnormalities in syndromic CHD. The identified CNVs and gene candidates offer new insights into CHD genetic architecture and support CMA as a first-tier diagnostic tool. These findings highlight the contribution of rare, pathogenic CNVs in syndromic cases and suggest their integration into refined diagnostic and counseling strategies. Further functional studies are necessary to elucidate the roles of these candidates in cardiogenesis. Show less

Acute myeloid leukemia (AML) is a clonal malignant disorder of the bone marrow. Genetic aberrations have an unequivocal role in disease pathogenesis. With the application of next-generation sequencing technologies (NGS), an enormous number of genetic fusions and variants has been detected. Their co-occurrence has an impact on patient`s prognosis. Therefore, our aim in this study was to survey fusion genes as well as their relation with genetic variants. Targeted sequencing of the following fusion genes, in bone marrow aspirate samples, was performed; MECOM, MET, MLLT10, MLLT3, MYBL1, MYH11 and NTRK3. In addition sequencing for the hot spot regions in the following genes was done: FLT3, KIT, NRAS, KRAS, HRAS, using OncomineTM myeloid research panel on Ion S5 NGS system. The study was conducted on 24 denovo Egyptian AML patients of both sexes. We identified one fusion in MYH11 gene (CBFB::MYH11) in two cases with four fusion transcripts of rare types. In addition, one novel breakpoint in MYH11 gene was identified. Also, about 337 variants in five genes were detected in all patients. Majority of them were benign. In the two positive cases for fusion; three pathogenic variants (2 KRAS, 1 NRAS), and one not-reported variant in FLT3 were reported. NGS has a major role in detection of genetic variants and fusions, which will have an impact on AML patient's prognosis. Show less

Congenital myasthenic syndromes (CMS) are a heterogeneous group of genetic disorders that give rise to a defect in neuromuscular transmission. We described here three patients with a characteristic phenotype of recessive CMS and presenting mutation in the gene encoding rapsyn (RAPSN). Familial analysis showed that one allelic mutation failed to be detected by direct sequencing. An allelic quantification on patient's DNA identified three novel multi-exon deletions of RAPSN. These three genomic rearrangements in RAPSN represent 15% of our CMS patients with RAPSN mutations and we emphasize that single-nucleotide polymorphism markers and a gene dosage method should be performed in addition to DNA direct sequencing analysis particularly when there is a genetic counselling issue. Show less