Biomedical subjects

Mieke M van Haelst

Publications and source records attributed to Mieke M van Haelst.

3 recordsLinked to original sources

PubMed2025

Discovery of a DNA methylation episignature as a molecular biomarker for fetal alcohol syndrome.

PURPOSE: Fetal alcohol spectrum disorder (FASD) encompasses a range of clinical features and neurodevelopmental disorders in children exposed to alcohol in utero. Despite its global public health significance, FASD diagnosis remains challenging because of nonspecific clinical findings and the lack of an accurate molecular diagnostic biomarker. This study aimed to evaluate peripheral blood DNA methylation (DNAm) profiles as a potential diagnostic biomarker for fetal alcohol syndrome. METHODS: Genomic DNAm profiles from 93 individuals with suspected or confirmed FAS, including a clinically diagnosed FAS subgroup, were analyzed and compared with a large database of control and patient cohorts with previously reported DNAm episignatures. Functional analysis of these DNAm profiles was performed to identify episignatures and assess their potential diagnostic utility. RESULTS: A relatively sensitive and specific DNAm episignature for FAS was identified. Comparative epigenomic analysis revealed functional correlations between FAS and other rare genetic disorders, supporting the robustness of the identified DNAm profiles as a diagnostic tool. CONCLUSION: This study demonstrates that unique DNAm profiles provide a robust episignature biomarker for FAS. These findings contribute to the molecular understanding of FAS and hold promise for improving diagnostic accuracy for this complex disorder.

Humans↗

PubMed2025

AUTS2-related syndrome: Insights from a large European cohort.

PURPOSE: AUTS2-related syndrome is characterized by developmental delay, autism spectrum disorder, and intellectual disability. From alternative promoters, AUTS2 encodes 2 distinct long and short isoforms encoding a putative transcriptional activator. METHODS: Through a European collaborative study, we collected clinical and genotype data on the largest AUTS2-related syndrome cohort of 58 patients harboring genomic rearrangements or single-nucleotide variants (SNVs). RESULTS: Pathogenic SNVs were recurrently found in individuals from different countries, suggesting mutational hotspots. Independent of the underlying defect at the AUTS2 locus, we observed that autistic behavior, hyperactivity, learning difficulties, and speech delay are common features of AUTS2-related syndrome. Among patients with SNVs, individuals carrying pathogenic variants affecting both longer and shorter AUTS2 transcripts showed a recognizable phenotype with microcephaly, brachycephaly, microretrognathia, broad nasal base, and anteverted nares. Behavioral disorders were more common in patients with variants affecting only the longer isoform. Arthrogryposis and stiff movements were only observed in patients with SNVs. CONCLUSION: This study provides a comprehensive clinical characterization of AUTS2-related syndrome, reveals few genotype-phenotype correlations, and suggests that the disruption of the 2 distinct AUTS2 transcripts has a different impact on the clinical phenotype.

Humans↗

PubMed2024

Microduplications of ARID1A and ARID1B cause a novel clinical and epigenetic distinct BAFopathy.

PURPOSE: ARID1A/ARID1B haploinsufficiency leads to Coffin-Siris syndrome, duplications of ARID1A lead to a distinct clinical syndrome, whilst ARID1B duplications have not yet been linked to a phenotype. METHODS: We collected patients with duplications encompassing ARID1A and ARID1B duplications. RESULTS: 16 ARID1A and 13 ARID1B duplication cases were included with duplication sizes ranging from 0.1 to 1.2 Mb (1-44 genes) for ARID1A and 0.9 to 10.3 Mb (2-101 genes) for ARID1B. Both groups shared features, with ARID1A patients having more severe intellectual disability, growth delay, and congenital anomalies. DNA methylation analysis showed that ARID1A patients had a specific methylation pattern in blood, which differed from controls and from patients with ARID1A or ARID1B loss-of-function variants. ARID1B patients appeared to have a distinct methylation pattern, similar to ARID1A duplication patients, but further research is needed to validate these results. Five cases with duplications including ARID1A or ARID1B initially annotated as duplications of uncertain significance were evaluated using PhenoScore and DNA methylation reanalysis, resulting in the reclassification of 2 ARID1A and 2 ARID1B duplications as pathogenic. CONCLUSION: Our findings reveal that ARID1B duplications manifest a clinical phenotype, and ARID1A duplications have a distinct episignature that overlaps with that of ARID1B duplications, providing further evidence for a distinct and emerging BAFopathy caused by whole-gene duplication rather than haploinsufficiency.

Humans↗