Peer-reviewed article
CD20 molecule deficiency and carrier frequency: a village-based screening study.
Ebru Sümen, Mehmet Ali Karaselek, Serkan Küççüktürk, Tuğçe Duran, Büşra Yüksel et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This is a medical screening study of a rare immune deficiency (CD20 deficiency) in a Turkish village population. The study screened 145 people to look for carriers of the genetic condition and to identify diagnostic markers using blood tests. No new cases were found, but about 10% of relatives showed carrier markers. The study concludes that flow cytometry testing could help identify carriers, though genetic confirmation is needed.
Key points
- 145 individuals from 52 families in one Turkish village were screened for CD20 deficiency
- No individuals with CD20 deficiency were identified beyond the known index case
- Approximately 10% of participants (n=14) showed CD20 expression patterns consistent with carrier status
- CD20 mean fluorescence intensity (MFI) was more informative than CD20 percentage for identifying carriers
- Flow cytometry may serve as a practical screening tool, but molecular genetic testing is needed to confirm carrier status
Limitations
This is a genetic screening study focused on identifying a very rare immune condition in one village, not an evaluation of health outcomes or interventions for child well-being. The study does not measure clinical impact or health improvements for affected children.
Abstract
BACKGROUND/AIM: CD20 deficiency is an autosomal recessive inborn error of immunity (IEI), and the only known affected individual worldwide has been under follow-up in our clinic. Because the consanguineous parents of the index patient are putative carriers, we hypothesized that additional individuals with reduced CD20 expression might exist within their village population. This study aimed to evaluate clinical features associated with IEI and to identify individuals displaying CD20 mean fluorescence intensity (MFI) patterns consistent with putative carrier status, while also providing appropriate genetic counseling. MATERIALS AND METHODS: This cross-sectional screening study was conducted in December 2024 in Çukurbağ village. Participants completed a questionnaire that included IEI warning signs and information about their familial relationship to the index case. CD19 and CD20 expression in peripheral blood samples was analyzed by flow cytometry. Individuals were classified as putative carriers if their CD20 MFI values were <50% of those of healthy controls. RESULTS: A total of 145 individuals (44 children, 101 adults) from 52 families were screened. Among individuals related to the index case, the consanguinity rate was 39.3%. Jeffrey Modell Foundation scores were significantly higher in children than in adults (p < 0.05). No individuals with CD20 deficiency were identified. Approximately 10% of participants (n = 14) exhibited normal CD19 and CD20 percentages but showed reduced CD20 MFI values consistent with putative carrier status. All putative carriers were relatives of the index case. The proposed CD20-A700 (≤2537) and CD20-FITC (≤7787) MFI thresholds demonstrated high diagnostic performance (sensitivity and specificity values are presented for both parameters). CONCLUSION: CD20 MFI, rather than CD20 percentage, appears to be a more informative indicator for identifying individuals with flow-cytometric patterns suggestive of putative carrier status. Flow cytometry may serve as a rapid and practical preliminary screening tool in community-based settings; however, confirmation of carrier status requires molecular genetic testing, and genetic counseling should be based on verified genotypic results.