Correlation between consanguineous marriages and age-standardized mortality rate due to breast cancer, an ecologic study

Variants in BRCA1/2 in a hospital-based cohort in Chile and national literature review

Purpose

The aim was to assess the diagnostic yield of next generation sequencing (NGS) multi-gene panels for breast and ovarian cancer in a high-complexity cancer centre in Chile. Additionally, our goal was to broaden the genotypic spectrum of BRCA variants already identified in Chilean families.

Methods

Retrospective analysis was conducted on the genetic test results of 722 individuals from Fundación Arturo López Pérez's genetic counselling unit between 2016 and 2021. A comprehensive literature review encompassing articles analysing the frequency of germinal pathogenic variants in BRCA1/2 within the Chilean population was undertaken.

Results

23.5% of the panels had positive results, with 60% due to pathogenic variants in the BRCA1/2 genes. Seven previously unreported variants in BRCA1 from Chilean studies were identified.One or more variants of uncertain significance were detected in 31% of the results, and 11.5% of the families in this cohort presented copy number variants (CNVs) in BRCA1/2.8 studies analysed the frequency of pathogenic variants in BRCA1/2 in the Chilean population between 2006 and 2023, with a frequency between 7.1% and 17.1%.51 BRCA1 variants in 149 families have been reported in Chile and 38 BRCA2 variants in 132 families. Nine founder pathogenic variants identified by one study were present in 51.9% of the total Chilean families reported.

Conclusion

Our findings advocate for the integration of NGS multi-gene panel testing as a primary strategy within our population. This approach allows for the comprehensive assessment of single nucleotide variants and CNVs in BRCA1/2, alongside other high and moderately penetrant genes associated with breast and ovarian cancer.

Interactions of Consanguinity and Number of Siblings with Childhood Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a common malignancy in children. Consanguinity has a high prevalence in developing countries and increases the probability of homozygosity for many genes which may affect ALL and its prognosis. We conducted a study to explore the impact of consanguinity and number of siblings on ALL as there are currently no studies to describe this effect. Data were collected from patients' records from the Children's University Hospital of Damascus University, which is the major cancer centre for children in Syria. This study included 193 children with ALL over one year. Number of siblings was not with the French-American-British (FAB) classification, gender, ALL subtype, or risk of ALL children. When comparing consanguinity degrees and complete blood counts at diagnosis, significant contradicting data were found in the third-degree and fourth-degree consanguinity when compared to one another and to not having consanguineous parents as third degree consanguinity was associated with normal platelets but lower WBC counts, and fourth-degree consanguinity was associated with normal haemoglobin levels and WBC counts, but lower platelet counts. Having consanguineous parents was also associated with acquiring ALL at an older age, L2 FAB classification, having a positive family history for malignancies, and not having hepatosplenomegaly (P < 0.05). Although L2 is known to be a poor prognosis indicatory, no association was found with consanguinity and risk. Finally, no association was found with ALL subtype or risk (P > 0.05). Although consanguinity and number of siblings have affected some variables and prognostic features of childhood ALL, the aetiology is not clear and we need further studies to clarify such an association as this will help in optimising therapy and accurately determine the risk.

Age-standardized Incidence Rates for Leukemia Associated with Consanguineous Marriages in 68 Countries, an Ecological Study

Consanguineous marriage that defines as a union between biologically related persons has a variety of known deleterious correlations with factors that affect public health within human populations. To investigate the association between the mean of inbreeding coefficient (α) and incidence of leukemia, the present ecological study on 68 countries was carried out. Statistical analysis showed that the age-standardized incidence rate of leukemia positively correlated with log₁₀GNI per capita (r=0.699, df=66, P<0.001) and negatively correlated with log_10α (r=−0.609, df=66, P<0.001). Controlling log₁₀GNI per capita, a significant negative correlation between log_10α and the age-standardized incidence rate of leukemia was observed (r=−0.392, df=65, P=0.001). The countries were stratified according to their annual GNI per capita, low and high-income countries with GNI per capita less than and more than 10,000$, respectively. Statistical analysis showed that in high-income countries, after controlling for log₁₀GNI per capita, the correlation between the age-standardized incidence rate of leukemia and log_10α was still significant (r=−0.600, df=36, P<0.001). It should be noted that there was no significant association between the age-standardized mortality rate due to leukemia and log_10α (P>0.05). The present finding indicates that the rate of leukemia, age-standardized for incidence, is lower in countries with a high prevalence of consanguineous marriages.