Clinical features and mutational analysis of X-linked agammaglobulinemia patients in Malaysia.

Background: Bruton's tyrosine kinase (BTK) is a cytoplasmic protein involved in the B cell development. X-linked agammaglobulinemia (XLA) is caused by mutation in the BTK gene, which results in very low or absent B cells. Affected males have markedly reduced immunoglobulin levels, which render them susceptible to recurrent and severe bacterial infections. Methods: Patients suspected with X-linked agammaglobulinemia were enrolled during the period of 2010-2018. Clinical summary, and immunological profiles of these patients were recorded. Peripheral blood samples were collected for monocyte BTK protein expression detection and BTK genetic analysis. The medical records between January 2020 and June 2023 were reviewed to investigate COVID-19 in XLA. Results: Twenty-two patients (from 16 unrelated families) were molecularly diagnosed as XLA. Genetic testing revealed fifteen distinct mutations, including four splicing mutations, four missense mutations, three nonsense mutations, three short deletions, and one large indel mutation. These mutations scattered throughout the BTK gene and mostly affected the kinase domain. All mutations including five novel mutations were predicted to be pathogenic or deleterious by in silico prediction tools. Genetic testing confirmed that eleven mothers and seven sisters were carriers for the disease, while three mutations were de novo. Flow cytometric analysis showed that thirteen patients had minimal BTK expression (0-15%) while eight patients had reduced BTK expression (16-64%). One patient was not tested for monocyte BTK expression due to insufficient sample. Pneumonia (n=13) was the most common manifestation, while Pseudomonas aeruginosa was the most frequently isolated pathogen from the patients (n=4). Mild or asymptomatic COVID-19 was reported in four patients. Conclusion: This report provides the first overview of demographic, clinical, immunological and genetic data of XLA in Malaysia. The combination of flow cytometric assessment and BTK genetic analysis provides a definitive diagnosis for XLA patients, especially with atypical clinical presentation. In addition, it may also allow carrier detection and assist in genetic counselling and prenatal diagnosis.

Asthma control and care among six public health clinic attenders in Malaysia: A cross-sectional study.

Background and Aims: Asthma is common in Malaysia but neglected. Achieving optimal asthma control and care is a challenge in the primary care setting. In this study, we aimed to identify the risk factors for poor asthma control and pattern of care among adults and children (5-17 years old) with asthma attending six public health clinics in Klang District, Malaysia. Methods: We conducted a cross-sectional study collecting patients' sociodemographic characteristics, asthma control, trigger factors, healthcare use, asthma treatment, and monitoring and use of asthma action plan. Descriptive statistics and stepwise logistic regression were used in data analysis. Results: A total of 1280 patients were recruited; 85.3% adults and 14.7% children aged 5-17 years old. Only 34.1% of adults had well-controlled asthma, 36.5% had partly controlled asthma, and 29.4% had uncontrolled asthma. In children, 54.3% had well-controlled asthma, 31.9% had partly controlled, and 13.8% had uncontrolled asthma. More than half had experienced one or more exacerbations in the last 1 year, with a mean of six exacerbations in adults and three in children. Main triggers for poor control in adults were haze (odds ratio [OR] 1.51; 95% confidence interval [CI] 1.13-2.01); cold food (OR 1.54; 95% CI 1.15-2.07), extreme emotion (OR 1.90; 95% CI 1.26-2.89); air-conditioning (OR 1.63; 95% CI 1.20-2.22); and physical activity (OR 2.85; 95% CI 2.13-3.82). In children, hot weather (OR 3.14; 95% CI 1.22-8.11), and allergic rhinitis (OR 2.57; 95% CI 1.13-5.82) contributed to poor control. The majority (81.7% of adults and 64.4% of children) were prescribed controller medications, but only 42.4% and 29.8% of the respective groups were compliant with the treatment. The importance of an asthma action plan was reported less emphasized in asthma education. Conclusion: Asthma control remains suboptimal. Several triggers, compliance to controller medications, and asthma action plan use require attention during asthma reviews for better asthma outcomes.

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

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.

Whole exome sequencing identifies compound heterozygous variants of CR2 gene in monozygotic twin patients with common variable immunodeficiency.

OBJECTIVES: A pair of female Malay monozygotic twins who presented with recurrent upper respiratory tract infections, hepatosplenomegaly, bronchiectasis and bicytopenia were recruited in this study. Both patients were suspected with primary immunodeficiency diseases. However, the definite diagnosis was not clear due to complex disease phenotypes. The objective of this study was to identify the causative gene mutation in these patients. METHODS: Lymphocyte subset enumeration test and whole exome sequencing were performed. RESULTS: We identified a compound heterozygous CR2 mutation (c.1916G>A and c.2012G>A) in both patients. These variants were then confirmed using Sanger sequencing. CONCLUSION: Whole exome sequencing analysis of the monozygotic twins revealed compound heterozygous missense mutations in CR2.

Case series of foreign body aspiration in Paediatric Institute, Hospital Kuala Lumpur.

A retrospective case series was conducted to determine the clinical characteristics and bronchoscopy findings of children with foreign body aspiration in Paediatric Institute, Hospital Kuala Lumpur. Ten boys and two girls were included (range 2-177 months; median 26 months old). They commonly presented with cough (12/100%) and difficulty in breathing (9/75%). All patients had unilateral auscultatory findings and the commonest radiographic findings were unilateral hyperinflation (7/58.3%). The majority of foreign bodies removed was organic (8/66.6%) and more frequently found in the left bronchial tree (7/58.3%). Major complications were pneumonia (11/91.6%) and airway oedema (11/ 91.6%). Eight patients had delayed diagnosis due to parents unawareness (6/50%) and missed diagnosis (2/16.7%).