Does the esv3587290 Copy-Number Variation in the VANGL1 Gene Differ as a Genetic Factor for Developing Nephritis in Mexican versus European Childhood-Onset Systemic Lupus Erythematosus Patients?

• DOI: 10.20944/preprints202405.0040.v1
• Publication Date: 2024-05-07T08:23:10Z
• Authors: MIGUEL ANGEL ALCÁ...; Ana Luisa Rodrígu...; Bernardette Estan...; Ariadna González-...; Luisa Díaz-García; Francisco Eduardo...; Ruth Guadalupe Ná...

A ~3-kb deletion-type DNA copy-number variation (CNV, esv3587290) located at intron 7 of the VANGL1 gene (1p13.1, MIM*610132) has been proposed as a genetic factor for developing lupus nephritis (LN) in adult systemic lupus erythematosus (SLE) patients across European-descent populations, but its replication in other ethnicities has been inconsistent and its association with LN in childhood-onset SLE (cSLE) remains unknown. Here, we performed an exploratory association study in a sample of 66 unrelated cSLE Mexican patients (11 males, 55 females; ages 7.8 to 18.6 years). Two stratified groups were compared: cSLE patients with (N=37) or without (N=29) LN, as diagnosed by renal biopsy (N=15), proteinuria (N=33), urinary protein:creatinine ratio >0.2 (N=34), and erythrocyturia and/or granular casts in urinary sediment (N=16). For esv3587290 CNV genotyping, we performed an end-point PCR assay with breakpoint confirmation by Sanger sequencing. We also determined the allelic frequencies of the esv3587290 CNV in 181 deidentified ethnically-matched individuals (reference group). The obtained genotypes were tested for Hardy-Weinberg equilibrium (HWE) by 2 test. Associations between LN and esv3587290 CNV were tested by calculating the Odds Ratio (OR) and using Pearson's 2 tests with a 95% confidence interval and p≤0.05. Contrary to the results described in European-descent populations, the esv3587290 CNV showed a significant protective effect against LN development (OR 0.14, 95% CI 0.066-0.31, p≤0.05), whereas the wild-type homozygous VANGL1 genotype showed a risk trend for LN development (OR 2.15, 95% CI 0.7711-6.18, p≤0.05). Finally, we characterized the precise breakpoint of the esv3587290 CNV as NG_016548.1(NM_138959.3):c.1314+1339_1315-897del (https://databases.lovd.nl/shared/variants/0000918418#00025811) in our population. This report supports the notion that a broad genetic heterogeneity underlies the susceptibility for developing LN.