Four novel and three recurrent mutations of the BTK gene and pathogenic effects of putative splice mutations

Wattanasirichaigoon, Duangrurdee; Benjaponpitak, Suwat; Techasaensiri, Chonnamet; Kamchaisatian, Wasu; Vichyanond, Pakit; Janwityanujit, Sucheela; Choubtum, Lulin; Sirinavin, Sayomporn

doi:10.1007/s10038-006-0052-y

Cited by 7 publications

(5 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the gene variant present in our patient (R562Q) had not been previously described, other variants have been reported in the same residue as being probably pathogenic (R562W, R562L, R562P) ( 26 – 30 ). One of these variants was present in a patient with low IgG levels but normal IgM and IgA levels ( 27 ). R562 is located in the Btk kinase domain in close proximity to the catalytic site and is involved in substrate binding and together with A582 is implicated in the interaction with the invariant W563 chain ( 31 ).…”

Section: Discussionmentioning

confidence: 99%

Research-based flow cytometry assays for pathogenic assessment in the human B-cell biology of gene variants revealed in the diagnosis of inborn errors of immunity: a Bruton’s tyrosine kinase case-study

et al. 2023

View full text Add to dashboard Cite

IntroductionInborn errors of immunity (IEI) are an expanding group of rare diseases whose field has been boosted by next-generation sequencing (NGS), revealing several new entities, accelerating routine diagnoses, expanding the number of atypical presentations and generating uncertainties regarding the pathogenic relevance of several novel variants.MethodsResearch laboratories that diagnose and provide support for IEI require accurate, reproducible and sustainable phenotypic, cellular and molecular functional assays to explore the pathogenic consequences of human leukocyte gene variants and contribute to their assessment. We have implemented a set of advanced flow cytometry-based assays to better dissect human B-cell biology in a translational research laboratory. We illustrate the utility of these techniques for the in-depth characterization of a novel (c.1685G>A, p.R562Q) de novo gene variant predicted as probably pathogenic but with no previous insights into the protein and cellular effects, located in the tyrosine kinase domain of the Bruton’s tyrosine kinase (BTK) gene, in an apparently healthy 14-year-old male patient referred to our clinic for an incidental finding of low immunoglobulin (Ig) M levels with no history of recurrent infections.Results and discussionA phenotypic analysis of bone marrow (BM) revealed a slightly high percentage of pre-B-I subset in BM, with no blockage at this stage, as typically observed in classical X-linked agammaglobulinemia (XLA) patients. The phenotypic analysis in peripheral blood also revealed reduced absolute numbers of B cells, all pre-germinal center maturation stages, together with reduced but detectable numbers of different memory and plasma cell isotypes. The R562Q variant allows Btk expression and normal activation of anti-IgM-induced phosphorylation of Y551 but diminished autophosphorylation at Y223 after anti IgM and CXCL12 stimulation. Lastly, we explored the potential impact of the variant protein for downstream Btk signaling in B cells. Within the canonical nuclear factor kappa B (NF-κB) activation pathway, normal IκBα degradation occurs after CD40L stimulation in patient and control cells. In contrast, disturbed IκBα degradation and reduced calcium ion (Ca2+) influx occurs on anti-IgM stimulation in the patient’s B cells, suggesting an enzymatic impairment of the mutated tyrosine kinase domain.

show abstract

Section: Discussionmentioning

confidence: 99%

Research-based flow cytometry assays for pathogenic assessment in the human B-cell biology of gene variants revealed in the diagnosis of inborn errors of immunity: a Bruton’s tyrosine kinase case-study

et al. 2023

View full text Add to dashboard Cite

show abstract

“…mit.edu/cgi-bin/primer3/primer3_www.cgi; Primer sequences are available as per request). Protocols for mRNA isolation, first stranded cDNA synthesis, and RT-PCR were as described elsewhere [7]. GenBank reference sequences were NT_024524, NM_000053.2, and NP_000044.…”

Section: Genetic Analysismentioning

confidence: 99%

Mutations of ATP7B gene in two Thai siblings with Wilson disease

et al. 2010

Self Cite

View full text Add to dashboard Cite

Background: Wilson disease (WD) is an autosomal recessive disorder of copper metabolism caused by mutations in ATP7B gene. Objective: Report the clinical data and mutation analysis of two Thai siblings suspected of WD. Subject and methods: A 13-year-old boy who presented with cirrhosis, arthralgia, hypoalbuminemia, and coagulopathy, and his 11-year-old sister who was asymptomatic but had hepatomegaly with elevation of transaminases, were studied. Mutation analysis of ATP7B gene and mRNA analysis was performed in both patients and their parents. Results: Investigations were consistent with WD, and their liver diseases improved after standard treatment for WD. DNA analyses in these two patients revealed two novel mutations, which were a deletion of the first 2bp of exon 6 (c.1870_1871delGA), and a single base substitution from A to G at nucleotide 4075 (c.4075A>G) in the exon 20 (p.M1359V). PCR-restriction digestion with NcoI restriction enzyme was employed as the second method for confirmation of the c.4075A>G mutation and for rapid screening in 100 chromosomes from unrelated healthy controls, and this variant was not present in the controls. The c.1870_1871delGA deletion caused a frameshift effect, which results in a premature stop codon (p.E624fsX753), and the p.M1359V mutation is a substitution of methionine with valine, which may have effects upon its orientation and interaction with other adjacent amino acids. Conclusion: Two novel mutations of ATP7B gene were identified in two Thai siblings with WD.

show abstract

“…The immunological tests were performed using standard techniques and included complete blood count with peripheral blood smear evaluation, serum immunoglobulins, antibody response to pneumococcal vaccine, lymphocyte phenotype (T, B, and natural killer cells) by flow cytometry, lymphocyte proliferation test, dihydrorhodamine assay, and CH50. Mutation analysis using genomic DNA for interleukin (IL)-2R, IL-7R, Bruton tyrosine kinase (BTK), and cytochrome b-245, beta polypeptide (CYBB) genes were done by previously described methods [38][39][40][41]. For IL12RB1 gene, coding regions of the IL12RB1 locus were polymerase chain reaction (PCR)-amplified using exon-specific primers (primer sequences available upon request).…”

Section: Immunologic Studiesmentioning

confidence: 99%

Clinical Characteristics and Outcomes of Primary Immunodeficiencies in Thai Children: An 18-year Experience from a Tertiary Care Center

et al. 2009

View full text Add to dashboard Cite

show abstract

Four novel and three recurrent mutations of the BTK gene and pathogenic effects of putative splice mutations

Cited by 7 publications

References 24 publications

Research-based flow cytometry assays for pathogenic assessment in the human B-cell biology of gene variants revealed in the diagnosis of inborn errors of immunity: a Bruton’s tyrosine kinase case-study

Research-based flow cytometry assays for pathogenic assessment in the human B-cell biology of gene variants revealed in the diagnosis of inborn errors of immunity: a Bruton’s tyrosine kinase case-study

Mutations of ATP7B gene in two Thai siblings with Wilson disease

Clinical Characteristics and Outcomes of Primary Immunodeficiencies in Thai Children: An 18-year Experience from a Tertiary Care Center

Contact Info

Product

Resources

About