Germline mutations in cancer predisposition genes among pediatric patients with cancer and congenital anomalies.

BACKGROUND: Childhood cancer has a poorly known etiology, and investigating the underlying genetic background may provide novel insights. A recognized association exists between non-chromosomal birth defects and childhood cancer susceptibility. METHODS: We performed whole-exome sequencing and chromosomal microarray analysis in a cohort of childhood cancer (22 individuals, 50% with congenital anomalies) to unravel deleterious germline variants. RESULTS: A diagnostic yield of 14% was found, encompassing heterozygous variants in bona fide dominant Cancer Predisposition Genes (CPGs). Considering candidate and recessive CPGs harboring monoallelic variants, which were also deemed to play a role in the phenotype, the yield escalated to 45%. Most of the deleterious variants were mapped in genes not conventionally linked to the patient's tumor type. Relevant findings were detected in 55% of the syndromic individuals, mostly variants potentially underlying both phenotypes. CONCLUSION: We uncovered a remarkable prevalence of germline deleterious CPG variants, highlighting the significance of a comprehensive genetic analysis in pediatric cancer, especially when coupled with additional clinical signs. Moreover, our findings emphasized the potential for oligogenic inheritance, wherein multiple genes synergistically increase cancer risk. Lastly, our investigation unveiled potentially novel genotype-phenotype associations, such as SETD5 in neuroblastoma, KAT6A in gliomas, JAG1 in hepatoblastomas, and TNFRSF13B in Langerhans cell histiocytosis. IMPACT: Novel gene-phenotype associations and candidate genes for pediatric cancer were unraveled, such as KAT6A in gliomas, SETD5 in neuroblastoma, JAG1 in hepatoblastomas, and TNFRSF13B in Langerhans cell histiocytosis. Our analysis revealed a high frequency of deleterious germline variants, particularly in cases accompanied by additional clinical signs, highlighting the importance of a comprehensive genetic evaluation in childhood cancer. Our findings also underscored the potential for oligogenic inheritance in pediatric cancer risk. Understanding the cancer etiology is crucial for genetic counseling, often influencing therapeutic decisions and offering valuable insights into molecular targets for the development of oncological therapies.

Polycystic Ovary Syndrome as a systemic disease with multiple molecular pathways: a narrative review.

Polycystic Ovary Syndrome (PCOS) is characterized by hyperandrogenism, amenorrhea, and polycystic ovaries. This endocrinopathy is associated with many metabolic disorders such as dyslipidemia and insulin resistance, with increased risk of type 2 diabetes mellitus, metabolic syndrome, and cardiovascular complications. Inflammation is likely to play an important role in the promoting these metabolic imbalances, while prothrombotic and pro-oxidative mechanisms further contribute to the cardiovascular risk of these patients. The etiology of PCOS is still not fully understood, but there is evidence of genetic and environmental components. This review aims to discuss some molecular pathways associated with PCOS that could contribute to the better understanding about this syndrome. Recent evidence suggests that intrauterine exposure of female mice to an excess of anti-Müllerian hormone may induce PCOS features in their post-natal life. High cytokine levels and cytokine gene polymorphisms also appear to be associated with the pathophysiology of PCOS. Furthermore, high levels of microparticles may contribute to the altered hemostasis and enhanced inflammation in PCOS. All these mechanisms may be relevant to clarify some aspects of PCOS pathogenesis and inspire new strategies to prevent the syndrome as well as treat its symptoms and mitigate the risk of long-term complications.

Haptoglobin levels, but not Hp1-Hp2 polymorphism, are associated with polycystic ovary syndrome.

PURPOSE: Proteomic studies suggest an association between haptoglobin (Hp) and polycystic ovary syndrome (PCOS). Hp is a classic inflammatory marker and binds to the intravascular hemoglobin, avoiding the oxidative damages that can be caused by free hemoglobin. Inflammation and oxidative stress are important in the pathogenesis of the PCOS, one of the most frequent metabolic diseases in women. METHODS: To validate these proteomic studies, we developed a controlled cross-sectional study that aimed to evaluate the Hp levels and allelic and genotypic frequencies of Hp1-Hp2 polymorphism in Brazilian women with PCOS. We also investigated the correlation between Hp levels and several important parameters in PCOS as follows: body mass index (BMI), waist circumference (WC), fasting glucose, post-prandial glucose, homeostatic model assessment (HOMA), lipid accumulation product (LAP), C-reactive protein (CRP), and metabolization test of tetrazolium salts (MTTs-serum antioxidant capacity). RESULTS: Plasma Hp levels were higher in the PCOS group than in controls [8.20 (4.04) g/L; 7.98 (3.31) g/L; p = 0.018]. No significant difference was observed in the frequency of Hp1-Hp2 genotypes under additive, recessive, or dominant model of inheritance between the PCOS and the control groups. Plasma Hp levels did not differ according to the genotype. However, plasma Hp showed a negative correlation with MTT (r = - 0.383; p = 0.028), as well as a positive correlation with CRP (r = 0.361; p = 0.014) in the PCOS group. CONCLUSION: Hp1-Hp2 polymorphism is not associated with PCOS but plasma Hp could be a potential biomarker for PCOS and its complications.

Metformin reduces total microparticles and microparticles-expressing tissue factor in women with polycystic ovary syndrome.

PURPOSE: The objective of this study was to evaluate the levels of total microparticles (MPs) and microparticles-expressing tissue factor (TFMPs) in women with polycystic ovarian syndrome (PCOS) who use metformin comparing to those who do not take metformin. METHODS: We quantified total MPs and TFMPs in the plasma of 50 patients with PCOS-13 of these women used metformin (850 mg 2×/day during at least 6 months) and the other 37 did not. For this purpose, the microparticles (MPs) were purified by differential centrifugation of the plasma and, subsequently, by flow cytometry, using annexin-V and CD142 as markers. RESULTS: Total MPs levels were lower in treated patients (59.58 ± 28.43 MPs/µL) when compared to untreated group (97.32 ± 59.42; p = 0.033). Plasma levels of TFMPs were also significantly lower in the group of patients who used metformin (1.10 ± 0.94 MPs/µL) when compared to untreated patients (2.20 ± 1.42 MPs/µL) (p = 0.003). CONCLUSIONS: Considering that metformin reduced the levels of total MPs and TFMPs, our results suggest that this mechanism could be involved in the antithrombotic metformin effect, corroborating with the indication of this drug in the PCOS treatment.

Skewed X-chromosome Inactivation in Women with Idiopathic Intellectual Disability is Indicative of Pathogenic Variants.

Intellectual disability (ID) is an early onset impairment in cognitive functioning and adaptive behavior, affecting approximately 1% of the population worldwide. Extreme skewing of X-chromosome inactivation (XCI) can be associated with ID phenotypes caused by pathogenic variants in the X chromosome. We analyzed the XCI pattern in blood samples of 194 women with idiopathic ID, using the androgen receptor gene (AR) methylation assay. Among the 136 patients who were informative, 11 (8%) presented with extreme or total XCI skewing (≥ 90%), which was significantly higher than expected by chance. Whole-exome data obtained from these 11 patients revealed the presence of dominant pathogenic variants in eight of them, all sporadic cases, resulting in a molecular diagnostic rate of 73% (8/11 patients). All variants were mapped to ID-related genes with dominant phenotypes: four variants in the X-linked genes DDX3X (an XCI escape gene; two cases), WDR45, and PDHA1, and four variants in the autosomal genes KCNB1, CTNNB1, YY1, and ANKRD11. Three of the autosomal genes had no obvious correlation with the observed XCI skewing. However, YY1 is a known transcriptional repressor that acts in the binding of the XIST long noncoding RNA on the inactive X chromosome, providing a mechanistic link between the pathogenic variant and the detected skewed XCI in the carrier. These data confirm that extreme XCI skewing in females with ID is highly indicative of causative X-linked pathogenic variants, and point to the possibility of identifying causative variants in autosomal genes with a XCI role.

A novel MYT1L mutation in a boy with syndromic obesity: Case report and literature review.

BACKGROUND: Pathogenic variants involving the MYT1L gene lead to an autosomal dominant form of syndromic obesity, characterized by polyphagia, intellectual disability/developmental delay, and behavioral problems, and that a characteristic facial phenotype does not seem to be recognizable. METHODS: Trio whole exome sequencing was performed in a 10-year-old Brazilian male presenting polyphagia, severe early-onset obesity, intellectual disability, speech delay, macrocephaly, frontal bossing, telecanthus, strabismus, and hypogenitalism. Additionally, we performed a literature review of patients carrying non-copy number MYT1L variants. RESULTS: A de novo genetic variant not previously reported in MYT1L (NM_015025.4:c.2990C>A) was identified in the proband and classified as pathogenic. From a literature search, 22 further patients carrying non-copy number MYT1L variants were identified, evidencing that although the associated phenotype is quite variable, intellectual disability/developmental and speech delays are always present. Further, most patients have obesity or overweight due to polyphagia. Macrocephaly, strabismus, behavioral problems, and hand/feet malformations are also recurrent features. CONCLUSIONS: We described the first Brazilian case of MYT1L related syndrome and highlighted clinical characteristics based on the literature. Other syndromic forms of obesity such as Prader-Willi, Bardet-Biedl, Börjeson-Forssman-Lehmann, MORM, Cohen, Alstrom, and Kleefstra type 1 syndromes should be considered in the differential diagnosis. Further, although obesity is frequent, it is not an obligatory feature of all carriers of MYT1L mutations.