Biomedical subjects

Clifton L Dalgard

Publications and source records attributed to Clifton L Dalgard.

3 recordsLinked to original sources

PubMed2026

Chromosome X-wide association study in multiple system atrophy identifies sex-differential risk loci.

The human X chromosome accounts for ∼5% of the genome. Despite its size, the role of X-chromosomal variants in human diseases is not well understood, mainly due to its distinct inheritance pattern and the frequent omission of sex chromosomes from genome-wide association studies. This study used whole-genome sequencing data from 888 multiple system atrophy (MSA) cases and 7128 controls to perform an X-chromosome-wide common variant association study. Our analyses revealed two sex-differential risk loci: one located at Xq28, associated with increased risk for MSA in females [index variant: rs4898389, odds ratio (OR) = 1.69, 95% confidence interval (CI) = 1.40-2.03, P-value = 2.43 × 10⁻⁸], and another at Xp22.2 within the TBL1X gene, identified in males (index variant: rs6638956, OR = 1.48, 95%CI = 1.26-1.73, P-value = 9.92 × 10⁻⁷). In the Xq28 locus, colocalization analyses pointed to FAM3A and PLXNA3 as genes of interest. These findings emphasize the vital role of sex-differential genetic factors in the pathogenesis of MSA.

Humans↗

PubMed2025

Well-differentiated systemic mastocytosis: Genetics, mast cell immunophenotypes, and KIT autophosphorylation.

BACKGROUND: Well-differentiated systemic mastocytosis (WDSM) is a rare myeloid neoplasm where the genetic etiology is often unknown. OBJECTIVE: We aimed to assess WDSM patients for novel KIT variants, mast cell (MC) aberrant immunophenotypes, and KIT autophosphorylation patterns. METHODS: Next-generation sequencing, MC immunophenotyping, and KIT autophosphorylation studies were performed. RESULTS: Among 454 SM patients, there were 432 with KIT p.D816V+ SM and 4 with KIT p.D816Y+ SM-notably, none of these patients had WDSM. Of the remaining patients, we identified 7 with WDSM (1.5%) and 2 relatives with mastocytosis in skin. Next-generation sequencing revealed that 6 of 9 subjects carried known or novel germline KIT variants corresponding to regions outside of codon 816. Three patients had germline KIT p.K509I; 2 had germline KIT p.A533D; 1 had two germline KIT variants p.F681L and p.M541L; and 3 had no KIT mutation. Intracellular expression of CD2 and CD25 and less robust expression of CD30 was observed in MCs from WDSM patients. By developing a novel transient transfection assay in 293T cells, we found that unlike KIT p.D816F/V/Y variants that exhibit nearly exclusive intracellular localization and strong ligand-independent autophosphorylation (class II), WDSM-associated KIT variants showed enhanced ligand-dependent autophosphorylation relative to wild type (class I). CONCLUSIONS: Our study doubles the number of KIT variants identified in WDSM patients. No KIT p.D816V+ SM patient had WDSM. Intracellular CD2 and CD25 expression was more robustly detected in MCs from WDSM patients compared to CD30.

Humans↗

PubMed2025

Next generation sequencing analysis reveals complex genetic architecture of childhood-onset systemic lupus erythematosus.

OBJECTIVES: Our current understanding of the genetic architecture of childhood-onset SLE (cSLE) is limited by a dearth of comprehensive genomic studies in cSLE. We have quantified the number of known rare and common SLE risk variants in a diverse cSLE cohort. We characterised type I interferon (IFN) gene expression scores along with genomic data. METHODS: We performed whole genome sequencing on 83 patients with cSLE and 109 unaffected parents and analysed sequences for known common and rare SLE-associated risk variants. Type I IFN gene expression was quantified on a subset of patients. We investigated the relationship between clinical phenotype, genomic profile and type I IFN signatures in this cohort. RESULTS: Patients with cSLE were enriched for common SLE risk variants compared with unaffected parents and controls. We identified rare SLE risk variants in 11% of individuals with cSLE; those with rare variants had earlier disease onset (<12 years) than those without variants. Patients with cSLE had elevated type I IFN gene expression compared with unaffected parents and controls, even though most patients were treated with immunosuppressive therapy. CONCLUSIONS: Patients with cSLE from this ancestrally and geographically diverse cohort are enriched for common cSLE risk variants compared with controls, and 11% carry a rare variant in known monogenic SLE risk genes. The relationship between rare and common risk variant burden is more complex than previously hypothesised. Our findings indicate that studying patients with cSLE is important for understanding genetic contributions to SLE pathogenesis.

Humans↗