Frequency of HLA‐DQ, susceptibility genotypes for celiac disease, in Brazilian newborns

• Published in: Molecular genetics & genomic medicine Vol. 6; no. 5; pp. 779 - 784
• Main Authors: Almeida, Fernanda C., Gandolfi, Lenora, Costa, Karina N., Picanço, Marilucia R. A., Almeida, Lucas M., Nóbrega, Yanna K. M., Pratesi, Riccardo, Pratesi, Claudia B., Selleski, Nicole
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01-09-2018; John Wiley and Sons Inc
• Subjects: Alleles; Autoimmune diseases; Brazil - epidemiology; Celiac disease; Celiac Disease - epidemiology; Celiac Disease - genetics; DQA1 protein; Female; frequency; Gene Frequency; Genetic Predisposition to Disease; Genotypes; Histocompatibility antigen HLA; HLA-DQ Antigens - genetics; HLA‐DQ2; HLA‐DQ8; Humans; Infant, Newborn; Male; Neonates; newborn; Original; polymerase chain reaction; Real-Time Polymerase Chain Reaction; Brazil; United States > US; celiac disease; HLA-DQ8; newborn; polymerase chain reaction; HLA-DQ2; frequency
• ISSN: 2324-9269; 2324-9269
• DOI: 10.1002/mgg3.444

Background
The frequency of HLA‐DQ2 and DQ8 predisposing genotypes for celiac disease (CD) has shown significant variation among different world regions and has not been previously determined among the highly interbred Brazilian population. The aim of this study was to investigate the frequency of these genotypes among Brazilian newborns (NB).
Methods
We typed DQA1*05 ‐ DQB1*02 (DQ2.5) and DQA1*03 ‐ DQB1*03:02 (DQ8) alleles in 329 NB using qPCR technique. Subsequently we confirmed our results by PCR‐SSP using a reference kit which further identified DQ2.2 (DQA1*02:01 ‐ DQB1*02).
Results
Among the 329 NB, using qPCR technique: 5 (1.52%) carried both DQ2.5 and DQ8 variants; 58 (17.63%) carried only DQ2.5 (DQA1*05 and DQB1*02) and 47 (14.29%) carried only the DQ8 (DQA1*03 and DQB1*03:02) variant. The use of the PCR‐SSP method yielded further information; among the 329 samples: 34 (10.34%) tested positive for DQ2.2 and among the 47 previously DQ8 positives samples, we found 10 (3.04%) that also tested positives for DQ2.2.
Conclusion
43.7% of the analyzed individual tested positive for at least one of the CD predisposing HLA‐DQ genotypes in our group of Brazilian NB. The highest frequency was found for DQ2.5 positive subjects (17.6%) followed by DQ8 (11.3%); DQ2.2 (10.3%); DQ8 and DQ2.2 (3.0%); DQ2.5 and DQ8 (1.5%). We found no positive sample for DQ2.5 associated with DQ2.2.
This study analyses the frequency of celiac disease predisposing variants in a highly interbreed population (the Brazilian population). We assessed this information by studying a representative sample of the country and using a faster and more specific approach developed by our research team and previously validated.