Publications by authors named "Kwai Cheng Chan"

4 Publications

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A single-center pilot study in Malaysia on the clinical utility of whole-exome sequencing for inborn errors of immunity.

Clin Exp Immunol 2021 Jun 1. Epub 2021 Jun 1.

Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.

Primary immunodeficiency diseases refer to inborn errors of immunity (IEI) that affect the normal development and function of the immune system. The phenotypical and genetic heterogeneity of IEI have made their diagnosis challenging. Hence, whole-exome sequencing (WES) was employed in this pilot study to identify the genetic etiology of 30 pediatric patients clinically diagnosed with IEI. The potential causative variants identified by WES were validated using Sanger sequencing. Genetic diagnosis was attained in 46.7% (14 of 30) of the patients and categorized into autoinflammatory disorders (n = 3), diseases of immune dysregulation (n = 3), defects in intrinsic and innate immunity (n = 3), predominantly antibody deficiencies (n = 2), combined immunodeficiencies with associated and syndromic features (n = 2) and immunodeficiencies affecting cellular and humoral immunity (n = 1). Of the 15 genetic variants identified, two were novel variants. Genetic findings differed from the provisional clinical diagnoses in seven cases (50.0%). This study showed that WES enhances the capacity to diagnose IEI, allowing more patients to receive appropriate therapy and disease management.
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http://dx.doi.org/10.1111/cei.13626DOI Listing
June 2021

Atypical Presentation of Severe Fungal Necrotizing Fasciitis in a Patient with X-Linked Agammaglobulinemia.

J Clin Immunol 2021 Aug 13;41(6):1178-1186. Epub 2021 Mar 13.

Primary Immunodeficiency Unit, Allergy and Immunology Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health, Selangor, Malaysia.

X-linked agammaglobulinemia is a rare primary immunodeficiency due to a BTK mutation. The patients are characteristically deficient in peripheral B cells and serum immunoglobulins. While they are susceptible to infections caused by bacteria, enteroviruses, and parasites, fungal infections are uncommon in XLA patients. Here, we report a boy of Malay ethnicity who suffered from recurrent upper respiratory tract infections and severe progressive necrotizing fasciitis caused by Saksenaea erythrospora. Immunological tests showed a B cell deficiency and hypogammaglobulinemia. Whole-exome sequencing identified a dinucleotide deletion (c.1580_1581del) in BTK, confirmed by Sanger sequencing and predicted to be disease causing by in silico functional prediction tools (Varsome and MutationTaster2) but was absent in the gnomAD database. This mutation resulted in a frameshift and premature termination (p.C527fs), which disrupted the protein structure. The mother was heterozygous at the mutation site, confirming her carrier status. Flow cytometric analysis of monocyte BTK expression showed it to be absent in the patient and bimodal in the mother. This study describes a novel BTK mutation in a defined hotspot and an atypical fungal phenotype in XLA. Further studies are required to understand the pathogenesis of fungal infection in XLA.
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http://dx.doi.org/10.1007/s10875-021-01017-3DOI Listing
August 2021

A novel de novo NLRC4 mutation reinforces the likely pathogenicity of specific LRR domain mutation.

Clin Immunol 2020 02 20;211:108328. Epub 2019 Dec 20.

Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia; Centre of Research in Systems Biology, Structural Bioinformatics and Human Digital Imaging (CRYSTAL), University of Malaya, Kuala Lumpur, Malaysia. Electronic address:

Autoinflammatory disorders are characterized by dysregulated innate immune response, resulting in recurrent uncontrolled systemic inflammation and fever. Gain-of-function mutations in NLRC4 have been described to cause a range of autoinflammatory disorders. We report a twelve-year-old Malay girl with recurrent fever, skin erythema, and inflammatory arthritis. Whole exome sequencing and subsequent bidirectional Sanger sequencing identified a heterozygous missense mutation in NLRC4 (NM_001199138: c.1970A > T). This variant was predicted to be damaging in silico, was absent in public and local databases and occurred in a highly conserved residue in the leucine-rich repeat (LRR) domain. Cytokine analysis showed extremely high serum IL-18 and IL-18/CXCL9 ratio, consistent with other NLRC4-MAS patients. In summary, we identified the first patient with a novel de novo heterozygous NLRC4 gene mutation contributing to autoinflammatory disease in Malaysia. Our findings reinforce the likely pathogenicity of specific LRR domain mutations in NLRC4 and expand the clinical spectrum of NLRC4 mutations.
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http://dx.doi.org/10.1016/j.clim.2019.108328DOI Listing
February 2020

Incidence and predictors of severe anemia in Asian HIV-infected children using first-line antiretroviral therapy.

Int J Infect Dis 2013 Oct 10;17(10):e806-10. Epub 2013 Jun 10.

HIV-NAT, the Thai Red Cross AIDS Research Center, 104 Ratchadamri Road, Pathumwan, Bangkok, Thailand 10330; Kirby Institute for Infection and Immunity in Society, UNSW, Sydney, Australia. Electronic address:

Background: There are limited data on treatment-related anemia in Asian HIV-infected children.

Methods: Data from Asian HIV-infected children aged <18 years on first-line highly active antiretroviral therapy (HAART) were used. Children who had pre-existing severe anemia at baseline were excluded. Anemia was graded using the United States Division of AIDS (DAIDS) 2004 table. Potential risk factors for severe anemia were assessed by logistic regression.

Results: Data from 1648 children (51.9% female, 62.8% World Health Organization (WHO) stage 3/4) were analyzed. Median (interquartile range) age was 6.8 (3.7-9.6) years, CD4% was 9 (3-16)%, and plasma HIV-RNA was 5.2 (4.7-5.6) log10 copies/ml at HAART initiation in those with available testing. The most common regimens were stavudine/lamivudine/nevirapine (42%) and zidovudine/lamivudine/nevirapine (25%). Severe anemia was identified in 47 (2.9%) children after a median time of 6 months after HAART initiation, with an incidence rate of 5.4 per 100 child-years. Mild anemia or moderate anemia at baseline (p = 0.024 and p = 0.005, respectively), previous or current use of zidovudine (p < 0.0001 and p = 0.013, respectively), and male sex (p = 0.008) were associated with severe anemia. Higher weight-for-age z-score (p = 0.004) was protective.

Conclusions: The incidence of severe anemia in Asian HIV-infected children after HAART initiation was low and mainly occurred during the first few months after HAART initiation. Mild to moderate anemia at baseline and using zidovudine were independent risk factors for the development of severe anemia.
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http://dx.doi.org/10.1016/j.ijid.2013.04.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4074526PMC
October 2013
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