Clinical characteristics and prenatal diagnosis for 22 families in Henan Province of China with X-linked agammaglobulinemia (XLA) related to Bruton’s tyrosine kinase (BTK) gene mutations

Abstract

Background: X-linked agammaglobulinaemia (XLA) is a rare immunodeficiency disease for which recurrent severe infection is the major clinical symptom. BTK is the main causative gene, with X chromosome recessive inheritance. However, the mutations reported to date do not fully explain the disorder. Methods: We detected the percentage of CD19+ B cells and serum immunoglobulin (IgG, IgA, and IgM) levels by flow cytometry and rate scatter immunoturbidimetry, and investigated the BTK mutation profile in 22 XLA patients using Sanger sequencing and real-time PCR. Results: We evaluated the clinical symptoms of 22 XLA patients and investigated genetic mutations present, identifying six novel mutations in the BTK gene: 2 missense mutations (c.23G > T and c.112 T > C), 2 frameshift mutations (c.522_523insC and c.1060delA), 1 large deletion (deletion of exon 2 to 5), and 1 splice-site mutation (c.1631 + 2 T > C). Prenatal diagnoses were performed in six families (F10, F11, F15, F18, F20 and F21), with the following results: the male fetus in Family 10 (F10) did not carry the c.922_923delGA mutation; the male fetus in Family 15 (F15) did not carry the c.1631 + 1G > T splicing mutation; the female fetus in Family 20 (F20) did not carry the c.1931 T > C mutation; the female fetus in Family 21 (F21) did not carry the large deletion mutation. Hence, these four fetuses are not likely to develop XLA. Male fetuses with c.1060delA and c.1684C > T mutations were identified in Family 11 and Family 18, respectively. The pregnant woman in F18 chose to terminate the pregnancy, whereas the pregnant woman in F11 chose to continue the pregnancy. Conclusion: We confirmed the diagnosis of 22 XLA patients from 22 unrelated families and detected six new pathogenic mutations. Prenatal diagnosis was performed in six families. Early genetic diagnosis and routine lifelong immunoglobulin replacement therapy can prevent and treat infections in XLA children, saving their lives.

Analysis of L1CAM gene mutation and imaging appearance in three Chinese families with L1 syndrome: Three case reports

“…Genomic DNA was extracted from the aborted fetus and peripheral leukocytes from the mothers and the grandma of the patients, according to standard protocols (Gao et al, 2020 ). Whole‐exon sequencing was used to analyze the gene variation and screen the candidate gene, followed by PCR and Sanger sequencing to confirm the L1CAM gene.…”

Inborn errors of immunity in mainland China: the past, present and future

“…These methods analyse fetal DNA to identify genetic mutations associated with IEI. Several studies have reported successful cases of prenatal diagnoses using these approaches, such as CGD, 32 44 45 WAS, 46 SCID, 35 XLA 47 and XLP. 48 Nevertheless, certain invasive techniques carry risks of miscarriage.…”

Multidisciplinary Approach to Primary Immunodeficiency Due to Defect in Innate Immunity: About a Case

“…Both children and their families may feel isolated and stigmatized in education, employment and the workplace, or lack social support or understanding [9,10]. Different studies have analyzed the quality of life in primary immunodeficiencies such as severe combined immunodeficiency due to RAG1 and RAG2 deficiency [10], common variable immunodeficiency [11] or X-linked immunodeficiency (Bruton's agammaglobulinemia) [12]. Among the immunodeficiencies by default in phagocytosis is chronic granulomatous disease (CGD).…”