IKZF1plus is a frequent biomarker of adverse prognosis in Mexican pediatric patients with B-acute lymphoblastic leukemia.

Background: Recurrent genetic alterations contributing to leukemogenesis have been identified in pediatric B-cell Acute Lymphoblastic Leukemia (B-ALL), and some are useful for refining classification, prognosis, and treatment selection. IKZF1plus is a complex biomarker associated with a poor prognosis. It is characterized by IKZF1 deletion coexisting with PAX5, CDKN2A/2B, or PAR1 region deletions. The mutational spectrum and clinical impact of these alterations have scarcely been explored in Mexican pediatric patients with B-ALL. Here, we report the frequency of the IKZF1plus profile and the mutational spectrum of IKZF1, PAX5, CDKN2A/2B, and ERG genes and evaluate their impact on overall survival (OS) in a group of patients with B-ALL. Methods: A total of 206 pediatric patients with de novo B-ALL were included. DNA was obtained from bone marrow samples at diagnosis before treatment initiation. A custom-designed next-generation sequencing panel was used for mutational analysis. Kaplan-Meier analysis was used for OS estimation. Results: We identified the IKZF1plus profile in 21.8% of patients, which was higher than that previously reported in other studies. A significantly older age (p=0.04), a trend toward high-risk stratification (p=0.06), and a decrease in 5-year Overall Survival (OS) (p=0.009) were observed, although heterogeneous treatment protocols in our cohort would have impacted OS. A mutation frequency higher than that reported was found for IKZF1 (35.9%) and CDKN2A/2B (35.9%) but lower for PAX5 (26.6%). IKZF1MUT group was older at diagnosis (p=0.0002), and most of them were classified as high-risk (73.8%, p=0.02), while patients with CDKN2A/2BMUT had a higher leukocyte count (p=0.01) and a tendency toward a higher percentage of blasts (98.6%, >50% blasts, p=0.05) than the non-mutated patients. A decrease in OS was found in IKZF1MUT and CDKN2A/2BMUT patients, but the significance was lost after IKZF1plus was removed. Discussion: Our findings demonstrated that Mexican patients with B-ALL have a higher prevalence of genetic markers associated with poor outcomes. Incorporating genomic methodologies into the diagnostic process, a significant unmet need in low- and mid-income countries, will allow a comprehensive identification of relevant alterations, improving disease classification, treatment selection, and the general outcome.

Germline mutations in pediatric cancer cohort with mixed-ancestry Mexicans.

BACKGROUND: Childhood cancer is one of the primary causes of disease-related death in 5- to 14-year-old children and currently no prevention strategies exist to reduce the incidence of this disease. Childhood cancer has a larger hereditary component compared with cancer in adults. Few genetic studies have been conducted on children with cancer. Additionally, Latin American populations are underrepresented in genomic studies compared with other populations. Therefore, the aim of this study is to analyze germline mutations in a group of mixed-ancestry Mexican pediatric patients with solid and hematological cancers. METHODS: We analyzed genetic variants from 40 Mexican childhood cancer patients and their relatives. DNA from saliva or blood samples was used for whole-exome sequencing. All variants were identified following GATK best practices. RESULTS: We found that six patients (15%) were carriers of germline mutations in CDKN2A, CHEK2, DICER1, FANCA, MSH6, MUTYH, NF1, and SBDS cancer predisposition genes, and additional new variants predicted to be deleterious by in silico algorithms. A population genetics analysis detected five components consistent with the demographic models assumed for modern mixed-ancestry Mexicans. CONCLUSIONS: This report identifies potential genetic risk factors and provides a better understanding of the underlying mechanisms of childhood cancer in this population.

Metabolic syndrome in indigenous communities in Mexico: a descriptive and cross-sectional study.

BACKGROUND: An Amerindian genetic background could play an important role in susceptibility to metabolic diseases, which have alarmingly increased in recent decades. Mexico has one of the highest prevalences of metabolic disease worldwide. The purpose of this study was to determine the prevalence of metabolic syndrome and its components in a population with high Amerindian ancestry. METHODS: We performed a descriptive, quantitative, and analytical cross-sectional study of 2596 adult indigenous volunteers from 60 different ethnic groups. Metabolic syndrome and its components were evaluated using the American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement criteria. RESULTS: The overall prevalence of metabolic syndrome in the indigenous Mexican population was 50.3%. Although females had a higher prevalence than males (55.6% vs. 38.2%), the males presented with combinations of metabolic syndrome components that confer a higher risk of cardiovascular disease. The most frequent metabolic syndrome component in both genders was low HDL-cholesterol levels (75.8%). Central obesity was the second most frequent component in females (61%), though it had a low prevalence in males (16.5%). The overall prevalence of elevated blood pressure was 42.7% and was higher in males than females (48.8 vs. 40%). We found no gender differences in the overall prevalence of elevated triglycerides (56.7%) or fasting glucose (27.9%). CONCLUSIONS: We documented that individuals with Amerindian ancestry have a high prevalence of metabolic syndrome. Health policies are needed to control the development of metabolic disorders in a population with high genetic risk.

[Birth defects associated with increased nuchal translucency]. / Defectos congénitos asociados con translucencia nucal aumentada.

BACKGROUND: Nuchal translucency is widely used to screen for trisomy 21 in the first trimester of pregnancy. It has also been associated with other chromosomal abnormalities, genetic syndromes and congenital defects. OBJECTIVE: To evaluate the perinatal outcome of patients who showed nuchal translucency greater or equal to 95th percentile during the first trimester ultrasound screening, which underwent fetal karyotype. MATERIAL AND METHOD: Case series. Fetuses with nuchal translucency greater or equal to 95th percentile were evaluated by fetal karyotype, second-trimester structural ultrasound scan, fetal echocardiography and postnatal clinical genetic evaluation, attended in the servicio de Genética of the Instituto Nacional de Perinatología Isidro Espinosa de los Reyes. RESULTS: 48 fetuses were evaluated. The karyotype was normal in 39 (81%) and abnormal in 9 (19%) cases of which three had trisomy 21, three monosomy X, two trisomy 18 and one 47,XYY In the cases with normal karyotype, 13 (33%) showed an abnormal second trimester ultrasound scan; among them, 12 had major congenital defects, 5 of them had abnormal cardiac findings that were confirmed by fetal echocardiography. In the group of 26 fetuses with normal karyotype and ultrasound, only 2 patients had minor birth defects. CONCLUSIONS: Increased fetal nuchal translucency is frequently associated with chromosomal abnormalities and several congenital defects, mostly heart defects and genetic syndromes. Our findings are in accordance with other published reports where a complete follow-up of all patients with increased nuchal translucency is recommended even if they have a normal karyotype, due to the increased risk of having other congenital defects or syndromic entities.