Publications by authors named "Tsz Fung Chan"

Hispanic/Latino children have the highest risk of acute lymphoblastic leukemia (ALL) in the US compared to other racial/ethnic groups, yet the basis of this remains incompletely understood. Through genetic fine-mapping analyses, we identified a new independent childhood ALL risk signal near IKZF1 in self-reported Hispanic/Latino individuals, but not in non-Hispanic White individuals, with an effect size of ∼1.44 (95% confidence interval = 1.

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Polygenic scores (PGS) are promising in stratifying individuals based on the genetic susceptibility to complex diseases or traits. However, the accuracy of PGS models, typically trained in European- or East Asian-ancestry populations, tend to perform poorly in other ethnic minority populations, and their accuracies have not been evaluated for Native Hawaiians. Using body mass index, height, and type-2 diabetes as examples of highly polygenic traits, we evaluated the prediction accuracies of PGS models in a large Native Hawaiian sample from the Multiethnic Cohort with up to 5,300 individuals.

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Article Synopsis
  • The study introduces HAMSTA, a new method for estimating heritability in mixed populations while correcting for biases caused by population structure.
  • Through simulations, HAMSTA demonstrates more accurate and unbiased heritability estimates compared to existing methods, especially in cases of ancestral stratification.
  • The application of HAMSTA to data from African American individuals revealed minimal bias in admixture mapping, indicating its effectiveness for evaluating heritability across multiple traits.
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The heritability explained by local ancestry markers in an admixed population provides crucial insight into the genetic architecture of a complex disease or trait. Estimation of can be susceptible to biases due to population structure in ancestral populations. Here, we present a novel approach, Heritability estimation from Admixture Mapping Summary STAtistics (HAMSTA), which uses summary statistics from admixture mapping to infer heritability explained by local ancestry while adjusting for biases due to ancestral stratification.

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Background: Pilocytic astrocytoma (PA) is the most common pediatric brain tumor. PA has at least a 50% higher incidence in populations of European ancestry compared to other ancestral groups, which may be due in part to genetic differences.

Methods: We first compared the global proportions of European, African, and Amerindian ancestries in 301 PA cases and 1185 controls of self-identified Latino ethnicity from the California Biobank.

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Epidemiological studies of obesity, Type-2 diabetes (T2D), cardiovascular diseases and several common cancers have revealed an increased risk in Native Hawaiians compared to European- or Asian-Americans living in the Hawaiian islands. However, there remains a gap in our understanding of the genetic factors that affect the health of Native Hawaiians. To fill this gap, we studied the genetic risk factors at both the chromosomal and sub-chromosomal scales using genome-wide SNP array data on ~4,000 Native Hawaiians from the Multiethnic Cohort.

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Whether certain variants of Epstein-Barr virus (EBV) are linked to the pathogenesis of nasopharyngeal carcinoma (NPC), which shows a marked geographic restriction, remains an unresolved issue. We performed a case-control study comparing genomic sequences of EBV isolated from saliva samples of 142 population carriers with those from primary tumour biopsies derived from 62 patients with NPC of Hong Kong. Cluster analysis discovered five EBV subgroups 1A-C and 2A-B amongst the population carriers in contrast to the predominance of 1A and -B in the majority of NPC.

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