Phenotypic and molecular characterization of five patients with PIK3CA-related overgrowth spectrum (PROS).

Somatic and germline PI3K-AKT-mTOR pathway pathogenic variants are involved in several segmental overgrowth phenotypes such as the PIK3CA-related overgrowth spectrum (PROS), Proteus syndrome, and PTEN hamartoma tumor syndrome. In this study, we describe five patients with PROS. We identified by high-throughput sequencing four different somatic PIK3CA pathogenic variants in five individuals. The Glu726Lys variant, which was previously reported in megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome, was identified in two patients with unclassified PROS. The Cys420Arg substitution, which was previously reported in CLOVES, was found in a patient with fibroadipose hyperplasia. Additionally, relatively rare pathogenic variants, His1047Tyr and Tyr1021Cys, were detected in two patients with MCAP. Therefore, we suggest performing deep sequencing of PIK3CA in all patients with suspected PROS, instead of targeted polymerase chain reaction for hotspot pathogenic variants.

Expression of Survivin and Its Splice Variants in Pediatric Acute Lymphoblastic Leukemia.

Aims: Survivin is involved in the inhibition of apoptosis and the regulation of cell division. In addition to wild-type survivin (survivin-wt), at least four splice variants with differential functions (ΔEx3 and 3B antiapoptotic, and 2α and 2B proapoptotic) have been identified. Survivin is highly expressed in several cancers, including hematological malignancies. Although acute lymphoblastic leukemia (ALL) is the most frequent malignancy in children, studies that investigated survivin expression in ALL are limited, and there is no study on 3B and 2α expression in ALL. Therefore the expression of survivin-wt and its splice variants was investigated in pediatric B-cell ALL patients. Materials and Methods: The expression of survivin-wt and its four splice variants was investigated by quantitative real-time polymerase chain reaction in archival RNA samples of 35 pediatric B-cell ALL patients. Patients were divided into high- and standard-risk groups according to age, white blood cell count, extramedullary involvement, and genetic risk factors; expression of survivin variants was compared between these two risk groups. Results: We found that the ratio of survivin-ΔEx3/wild type (WT) expression was higher in the low-risk group than in the high-risk group. Conclusion: Comparative analysis between the high- and low-risk B-cell ALL groups indicated that the survivin-ΔEx3/WT expression ratio could potentially be used in risk classification for pediatric B-cell ALL.

WNT Signaling Perturbations Underlie the Genetic Heterogeneity of Robinow Syndrome.

Locus heterogeneity characterizes a variety of skeletal dysplasias often due to interacting or overlapping signaling pathways. Robinow syndrome is a skeletal disorder historically refractory to molecular diagnosis, potentially stemming from substantial genetic heterogeneity. All current known pathogenic variants reside in genes within the noncanonical Wnt signaling pathway including ROR2, WNT5A, and more recently, DVL1 and DVL3. However, ∼70% of autosomal-dominant Robinow syndrome cases remain molecularly unsolved. To investigate this missing heritability, we recruited 21 families with at least one family member clinically diagnosed with Robinow or Robinow-like phenotypes and performed genetic and genomic studies. In total, four families with variants in FZD2 were identified as well as three individuals from two families with biallelic variants in NXN that co-segregate with the phenotype. Importantly, both FZD2 and NXN are relevant protein partners in the WNT5A interactome, supporting their role in skeletal development. In addition to confirming that clustered -1 frameshifting variants in DVL1 and DVL3 are the main contributors to dominant Robinow syndrome, we also found likely pathogenic variants in candidate genes GPC4 and RAC3, both linked to the Wnt signaling pathway. These data support an initial hypothesis that Robinow syndrome results from perturbation of the Wnt/PCP pathway, suggest specific relevant domains of the proteins involved, and reveal key contributors in this signaling cascade during human embryonic development. Contrary to the view that non-allelic genetic heterogeneity hampers gene discovery, this study demonstrates the utility of rare disease genomic studies to parse gene function in human developmental pathways.

Association Between N363S and BclI Polymorphisms of the Glucocorticoid Receptor Gene (NR3C1) and Glucocorticoid Side Effects During Childhood Acute Lymphoblastic Leukemia Treatment.

OBJECTIVE: Glucocorticoids (GCs) are the key drugs for the treatment of pediatric acute lymphoblastic leukemia (ALL). Herein, investigation of the relationship between the N363S and BclI polymorphisms of the GC receptor gene (NR3C1) and the side effects of GCs during pediatric ALL therapy was aimed. MATERIALS AND METHODS: N363S and BclI polymorphisms were analyzed in 49 patients with ALL treated between 2000 and 2012. The control group consisted of 46 patients with benign disorders. The side effects of GCs noted during the induction and reinduction periods were evaluated retrospectively according to the National Cancer Institute's Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: The BclI allele and genotype frequencies were found similar in the two groups. No N363S polymorphism was detected in either of the groups. During induction, dyspepsia was found more frequently in the CG than in the CC (wild-type) genotype (36.4% vs. 5.3%, p=0.018) and depression symptoms more frequent in patients with the G allele (CG+GG) than the CC genotype (39.3% vs. 10.5%, p=0.031). During reinduction, Cushingoid changes, dyspepsia, and depression symptoms were more frequent in patients with the G allele (CG+GG) than in patients with the CC genotype (48.1% vs. 17.6%, p=0.041; 29.6% vs. 0.0%, p=0.016; 40.7% vs. 11.8%, p=0.040, respectively). CONCLUSION: In our study, patients with the BclI polymorphism were found to have developed more frequent side effects. We think that the BclI polymorphism should be considered while designing individualized therapies in childhood ALL.

CYP1A1, GST gene polymorphisms and risk of chronic myeloid leukemia.

PRINCIPLES: Associations between polymorphisms for genes encoding enzymes involved in biotransformation of xenobiotics and susceptibility to several cancers have been shown in several studies. The aim of the present study is to investigate the influence of cytochromes P450 (CYP450) 1A1*2C and Glutathione S-transferases (GSTs) (T1 and M1) gene polymorphisms in susceptibility to chronic myeloid leukaemia (CML). METHODS: The frequency of CYP1A1 Ile/Val alleles and of GSTT1 and GSTM1 homozygous deletions was examined in 107 patients with CML and 132 healthy controls by PCR and/or PCRRFLP methods using blood samples. RESULTS: The frequency of CYP1A1 Val allele was found to be 19.2% in CML patients and 4.4% for controls, indicating that persons carrying this allele had an increased risk of CML (OR = 5.10, 95% CI: 2.60-9.97). The frequency of individuals carrying the GSTT1 null genotype was higher among CML patients (40.2%) compared to controls (19.2%) (OR = 2.82, 95% CI: 1.58-5.05; p <0.001). Therefore, GSTT1 present genotype may be a protective factor for CML. Although GSTM1 null genotype frequency was slightly higher in the patient group (44.9%) than in the controls (42.3%), this difference was not statistically significant (OR = 1.11, 95% CI: 0.66-1.86; p = 0.693). Individuals with GSTM1 null genotypes without the T allele have a 5.981 higher risk for CML than those who have the T allele. CONCLUSIONS: This data suggests that polymorphic CYP1A1 and GSTT1 genes appear to affect susceptibility to CML.