a Background and Aim. Sotos syndrome 2 (MIM #614753), known also as Malan syndrome, is caused by heterozygous mutations/deletions of the NFIX gene located on chromosome 19p13.2. It manifests in developmental delay, intellectual impairment, macrocephaly, central nervous system anomalies, postnatal overgrowth, and craniofacial dysmorphism. Unusual behavior with/without autistic traits, ophthalmologic, gastrointestinal, musculo-skeletal, and hand/foot abnormalities are also frequent. Due to the limited number of such cases, no definitive conclusions about genotypephenotype correlations have been possible. In the following paper, we discuss physical features consistent with Sotos syndrome 2 based on literature review and two new cases [a patient with de novo 19p13.2 deletion encompassing a part of the NFIX gene and a patient with de novo (not described so far) heterozygous missense mutation c.367C>T (p.Arg123Trp) in the NFIX gene]. Results. Apart from overgrowth and psychomotor developmental delay, the most consistent physical features of our two patients are dysmorphism including high forehead, downslanting palpebral fissures, pointed chin, and abnormalities of the pinna. Both show abnormal behavior and present with long, tapered fingers and toenail defect. No severe congenital malformations were noted. Conclusions. We hope these data will serve as a material for further studies and provide an opportunity to make more reliable genotype-phenotype correlations.
BackgroundThe defects in DNA repair genes are potentially linked to development and response to therapy in medulloblastoma. Therefore the purpose of this study was to establish the spectrum and frequency of germline variants in selected DNA repair genes and their impact on response to chemotherapy in medulloblastoma patients.MethodsThe following genes were investigated in 102 paediatric patients: MSH2 and RAD50 using targeted gene panel sequencing and NBN variants (p.I171V and p.K219fs*19) by Sanger sequencing. In three patients with presence of rare life-threatening adverse events (AE) and no detected variants in the analyzed genes, whole exome sequencing was performed. Based on combination of molecular and immunohistochemical evaluations tumors were divided into molecular subgroups. Presence of variants was tested for potential association with the occurrence of rare life-threatening AE and other clinical features.ResultsWe have identified altogether six new potentially pathogenic variants in MSH2 (p.A733T and p.V606I), RAD50 (p.R1093*), FANCM (p.L694*), ERCC2 (p.R695C) and EXO1 (p.V738L), in addition to two known NBN variants. Five out of twelve patients with defects in either of MSH2, RAD50 and NBN genes suffered from rare life-threatening AE, more frequently than in control group (p = 0.0005). When all detected variants were taken into account, the majority of patients (8 out of 15) suffered from life-threatening toxicity during chemotherapy.ConclusionOur results, based on the largest systematic study performed in a clinical setting, provide preliminary evidence for a link between defects in DNA repair genes and treatment related toxicity in children with medulloblastoma. The data suggest that patients with DNA repair gene variants could need special vigilance during and after courses of chemotherapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-017-3211-y) contains supplementary material, which is available to authorized users.
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