LifeCourse A Melbourne Children's Research Initiative

The Peri/Post-natal Epigenetic Twins Study (PETS)

PETS is a study of twins, from when they were in the womb through to childhood and beyond. The study aims to identify what makes us all who we are; our health, development and well being. Where better to start than with twins, who share the same mother, but are usually in their own ‘sac’ during pregnancy, then share the same home environment as children. Despite this, even ‘identical’ twins can have different personalities, physical characteristics and illnesses. Why is this?

Year	2007-2009	2007-2009	2007-2009	2007-2009	2008-2011	2014-2016	2018-Ongoing
Wave	1	2	3	4	5	6	7
Age	12 weeks gestation	13-24 weeks gestation	25 weeks to Birth	Birth	18 months	6 years	11 years
N	250 pairs	250 pairs	250 pairs	250 pairs	250 pairs	224 pairs	111 pairs (In progress)
RELEVANT LIFECOURSE DOMAINS					Allergies
	Anthropometrics
			Bioanalyses and omics
			Biosamples
						Cardiovascular health
	Demographics			Demographics		Demographics
	Education and childcare					Education and childcare
					Environmental exposures
						Family environment
				Health services
					Hearing
		Imaging					Imaging
	Medications and supplements				Medications and supplements
			Mental health and behaviour problems			Mental health and behaviour problems
						Methodology
						Neurocognitive development
	Nutrition		Nutrition		Nutrition
	Other health information				Other health information
							Physical activity
						Physical appearance
	Pregnancy and birth		Pregnancy and birth
							Psychosocial wellbeing
							Puberty
						Respiratory health
						Sleep
					Speech and language
	Substance use					Substance use

Study Summary
Study name	The Peri/Post-natal Epigenetic Twins Study
Study abbreviation	PETS
Current principal investigator/s	Prof Jeffrey Craig Richard Saffery
Current project manager	Jane Loke
Primary Institution/s	Murdoch Children’s Research Institute - MCRI
Collaborating Institution/s	The University of Melbourne - UoM Deakin University Australian Institute of Family Studies La Trobe University Royal Women’s Hospital Mercy Hospital for Women Monash Medical Centre
Major funding source/s	National Health and Medical Research Council - NHMRC Bonnie Babes Foundation Sigrid Juselius Foundation Academy of Finland Finnish Cultural Foundation Financial Markets Foundation for Children Victorian Government’s Operational Infrastructure Support Program
Study website	https://www.mcri.edu.au/peripostnatal-epigenetic-twins-study-pets
Key reference for study	Saffery, R., Morley, R., Carlin, J.B., Joo, J.H.E., Novakovic, B., Andronikos, R., Ollikainen, M., Li, X., Loke, Y.J., Carson, N., Wallace, E.M., Umstad, M.P., Permezel, M., Galati, J. and Craig, J.M. (2012). Cohort Profile: Peri/postnatal Epigenetics Twins Study. International Journal of Epidemiology, 41, 55-61. Loke Y.J., Novakovic B., Ollikainen M., Wallace E.M., Umstad, M.P., Permezel M., Morley R., Ponsonby A.L., Gordon L., Galati J.C., Saffery R. and Craig J.M. (2013) The Peri/Postnatal Epigenetic Twins Study (PETS). Twin research and human genetics: the official journal of the International Society for Twin Studies, 16, 13-20. Leong P, Loke YJ, Saffery R, Silk T, Burnett A, Josev E, Scurrah K, Theda C, Czajko A, Pua EP, Seal ML, Craig JM. Epigenetic influences on neurodevelopmental at 11 years of age: Protocol for the longitudinal peri/postnatal epigenetic twins study at 11 years of age (PETS@11). Twins Res. Hum. Genet. 2020 Feb. doi: 10.1017/thg.2019.120
Study focus	Investigating whether epigenetic marks measured at birth and early life can provide clues to the causal links between intrauterine exposures influencing perinatal phenotype and the risk of chronic diseases later in life.
Sampling frame	Women attending multiple pregnancy clinics at 3 Melbourne (Australia) hospitals (Royal Women’s Hospital, Monash Medical Centre, Mercy Hospital for Women) who were 18-22 weeks gestation.
Primary study type	Longitudinal cohort
Primary participant (at recruitment)	Index child
Year commenced	2007
Is this study ongoing?	Yes - the study is ongoing
Ongoing recruitment?	Yes
Sample size (N)	250 twin pairs and mothers
Survey data available?	Yes
Imaging data available?	Yes
Linkage to administrative dataset/s?	No, consent to link to administrative dataset(s) obtained, but linkage not yet started
Biosamples available?	Yes
Are data available to others outside study team, with appropriate safeguards and structures in line with the cohort’s ethics and governance processes?	Yes
Are there any costs associated with data/sample access for approved requests?	There are usually no costs associated with access
Broadest type of participant consent available	Extended consent (can be used for future ethically approved research related to this project)

Wave	Year	Age	Sample size (N)
1	2007-2009	12 weeks gestation	250 pairs
2	2007-2009	13-24 weeks gestation	250 pairs
3	2007-2009	25 weeks to Birth	250 pairs
4	2007-2009	Birth	250 pairs
5	2008-2011	18 months	250 pairs
6	2014-2016	6 years	224 pairs
7	2018-Ongoing	11 years	IN PROGRESS

Study Contacts
Principal investigator/s	Prof Jeffrey Craig Richard Saffery
Project manager	Jane Loke
Study Contact	Email: twins.study@mcri.edu.au Address: PETS Study Murdoch Children's Research Institute, Royal Children’s Hospital Flemington Road, Parkville Victoria 3052 Australia