P–617 Idiopathic early ovarian aging: Do biomarkers of ageing indicate premenopausal accelerated biological ageing in young women with diminished response to ART?

Study question

Do young women with idiopathic early ovarian ageing have changes in telomere length and epigenetic age indicating accelerated biological aging?

Summary answer

The telomere length and epigenetic age were comparable to those in young women with normal ovarian ageing.

What is known already

Increased risk of several health events usually considered to be age-related such as cardiovascular disease, osteoporosis, over-all morbidity and mortality have been associated with premature and early menopause when compared to the risk in women with normal menopausal age suggesting an accelerated general ageing process associated to early ovarian ageing. It is unclear whether the onset of this process may start before menopause.

Study design, size, duration

A prospective cohort study. Young women (≤ 37 years) having ART at two Danish Public fertility clinics during the period 2016 to 2018 were divided into two groups dependent on their ovarian reserve status: early ovarian ageing (EOA) (N = 55) and normal ovarian ageing (NOA)( N = 52). Number of oocytes harvested in first and subsequent cycles was used as a marker of ovarian reserve. Blood samples was drawn at time of oocyte retrieval to assess biological age.

Participants/materials, setting, methods

EOA was defined as ≥ 2 IVF cycles with ≤ 5 harvested oocytes despite sufficient stimulation with FSH and NOA as ≥ 8 oocytes harvested in minimum 1 cycle. Known causes influencing the ovarian reserve (endometriosis, ovarian surgery, etc.) was reason for exclusion. Relative telomere length (qPCR) and epigenetic age acceleration (DNA methylation levels) were measured in white blood cells as markers of accelerated biological ageing.

Main results and the role of chance

Relative telomere length was comparable with a mean of 0.46 (± sd 0.12) in the EOA group and 0.47 (0.14) in the normal ovarian ageing group (p = 0.64). The difference of predicted mean epigenetic age and mean chronological age (i.e. epigenetic age acceleration) was, insignificantly, 0.5 years older in the EOA group when compared to the NOA group( (–1.02 years (2.62) and –1.57 years (2.56), respectively, p = 0.27)), but this difference disappeared when adjusting for chronological age.

Limitations, reasons for caution

Discrete changes in epigenetic age acceleration may not have been captured as the study only had power to detect an age acceleration of ≥ 2 years.

Wider implications of the findings: By analysis of biomarkers for ageing in whole blood, we did not find any indications of a premenopausal accelerated aging in young women with idiopathic EOA. Further investigations in a similar cohort of premenopausal women is needed to fully elucidate the potential relationship between premenopausal accelerated biological ageing and EOA.

Trial registration number

The study was approved by the Danish Data protection Agency (nr 1–16–02–320–14) and the Regional committee on health research ethics of Central Region Denmark (jr.no 1–10–72–142–14).

4259Discovery of the first genome-wide significant risk loci for syncope and collapse

Background

Syncope is a common condition in the general population causing frequent hospitalisation and visits to the emergency department. Family aggregation and twin studies have previously indicated that syncope and collapse has a heritable component.

Purpose

We investigated whether common genetic variants predispose to syncope and collapse.

Methods

We used genome-wide association data on syncope and collapse for 408,961 individuals with European ancestry from the UK Biobank study. In a replication study, the Integrative Psychiatric Research Consortium (iPSYCH) cohort (n=86,189) was used to investigate the risk of incident syncope stratified by genotype carrier status.

Results

We report on a genome-wide significant locus on chromosome 2q32.1 with the lead SNP rs12465214 (odds ratio [OR] = 1.13, 95% confidence interval [CI] = 1.10–1.17, P=5.8x10–15; Figure 1a). This association was replicated in the iPSYCH cohort, where homozygous carriers of the C allele conferred an increased hazard ratio (HR=1.30, CI: 1.15–1.46, P=1.68x10–5; Figure 1b). LD score regression demonstrated a significant genetic correlation (rg) with coronary artery disease (rg=0.41, P=6.99x10–15) and related phenotypes such as angina and hypertension (Figure 1c). Analyses of eQTL (P=4x10–8) and epigenetic chromatin states revealed that variation in this locus likely affects expression of the gene ZNF804A, which resides in its proximity (Figure 1d). A qPCR analysis showed that ZNF804A was mostly expressed in the brain. A lower level of ZNF804A expression was also detected in the cerebral arteries. ZNF804A was not expressed in heart tissue.

Figure 1

Conclusion

rs12465214 is associated with syncope and collapse. Variation in this locus likely modulates the expression of the nearby gene ZNF804A through eQTLs and chromatin interactions. ZNF804A is mainly expressed in the brain and cerebral arteries. However, the precise function of ZNF804A is unknown. Furthermore, syncope and collapse is a polygenetic trait and share a significant genetic overlap with coronary artery disease, angina and hypertension.

Acknowledgement/Funding

This work was supported by grants from The John and Birthe Meyer Foundation, The Research Foundation of the Heart Centre, Rigshospitalet, The Research

The iPSYCH2012 case-cohort sample: new directions for unravelling genetic and environmental architectures of severe mental disorders

The Integrative Psychiatric Research (iPSYCH) consortium has established a large Danish population-based Case-Cohort sample (iPSYCH2012) aimed at unravelling the genetic and environmental architecture of severe mental disorders. The iPSYCH2012 sample is nested within the entire Danish population born between 1981 and 2005, including 1 472 762 persons. This paper introduces the iPSYCH2012 sample and outlines key future research directions. Cases were identified as persons with schizophrenia (N=3540), autism (N=16 146), attention-deficit/hyperactivity disorder (N=18 726) and affective disorder (N=26 380), of which 1928 had bipolar affective disorder. Controls were randomly sampled individuals (N=30 000). Within the sample of 86 189 individuals, a total of 57 377 individuals had at least one major mental disorder. DNA was extracted from the neonatal dried blood spot samples obtained from the Danish Neonatal Screening Biobank and genotyped using the Illumina PsychChip. Genotyping was successful for 90% of the sample. The assessments of exome sequencing, methylation profiling, metabolome profiling, vitamin-D, inflammatory and neurotrophic factors are in progress. For each individual, the iPSYCH2012 sample also includes longitudinal information on health, prescribed medicine, social and socioeconomic information, and analogous information among relatives. To the best of our knowledge, the iPSYCH2012 sample is the largest and most comprehensive data source for the combined study of genetic and environmental aetiologies of severe mental disorders.

Differential DNA methylation at birth associated with mental disorder in individuals with 22q11.2 deletion syndrome

Individuals with 22q11.2 deletion syndrome (DS) have an increased risk of comorbid mental disorders including schizophrenia, attention deficit hyperactivity disorder, depression, as well as intellectual disability. Although most 22q11.2 deletion carriers have the long 3-Mb form of the hemizygous deletion, there remains a large variation in the development and progression of psychiatric disorders, which suggests that alternative factors contribute to the pathogenesis. In this study we investigated whether neonatal DNA methylation signatures in individuals with the 22q11.2 deletion associate with mental disorder later in life. DNA methylation was measured genome-wide from neonatal dried blood spots in a cohort of 164 individuals with 22q11.2DS, including 48 individuals diagnosed with a psychiatric disorder. Among several CpG sites with P-value<10-6, we identified cg23546855 (P-value=2.15 × 10-7) mapping to STK32C to be associated with a later psychiatric diagnosis. Pathway analysis of the top findings resulted in the identification of several Gene Ontology pathways to be significantly enriched (P-value<0.05 after Benjamini-Hochberg correction); among them are the following: neurogenesis, neuron development, neuron projection development, astrocyte development, axonogenesis and axon guidance. In addition, we identified differentially methylated CpG sites in LRP2BP (P-value=5.37 × 10-8) to be associated with intellectual disability (F70-79), in TOP1 (P-value=1.86 × 10-7) with behavioral disorders (F90-98), in NOSIP (P-value=5.12 × 10-8) with disorders of psychological development (F80-89) and in SEMA4B (P-value=4.02 × 10-7) with schizophrenia spectrum disorders (F20-29). In conclusion, our study suggests an association of DNA methylation differences at birth with development of mental disorder later in life in 22q11.2DS individuals.