Heritability of young- and old-onset ischaemic stroke.
OBJECTIVE
Although the genetic contribution to stroke risk is well known, it remains unclear if young-onset stroke has a stronger genetic contribution than old-onset stroke. This study aims to compare the heritability of ischaemic stroke risk between young and old, using common genetic variants from whole-genome array data in population-based samples.


METHODS
This analysis included 4050 ischaemic stroke cases and 5765 controls from six study populations of European ancestry; 47% of cases were young-onset stroke (age < 55 years). To quantify the heritability for stroke risk in these unrelated individuals, the pairwise genetic relatedness was estimated between individuals based on their whole-genome array data using a mixed linear model. Heritability was estimated separately for young-onset stroke and old-onset stroke (age ≥ 55 years).


RESULTS
Heritabilities for young-onset stroke and old-onset stroke were estimated at 42% (±8%, P < 0.001) and 34% (±10%, P < 0.001), respectively.


CONCLUSIONS
Our data suggest that the genetic contribution to the risk of stroke may be higher in young-onset ischaemic stroke, although the difference was not statistically significant.
Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA.
A
A
Bluher
Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.|Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
W J
WJ
Devan
Public Health Program, Hunter Medical Research Institute, Newcastle, NSW, Australia.|School of Medicine and Public Health, University of Newcastle, Newcastle, NSW, Australia.
E G
EG
Holliday
Laboratory of Neurogenetics, National Institute of Aging, National Institute of Health, Bethesda, MD, USA.
M
M
Nalls
Institute of Molecular Genetics, National Research Council, Pavia, Italy.
S
S
Parolo
Institute of Molecular Genetics, National Research Council, Pavia, Italy.
S
S
Bione
Albrecht-Kossel-Institute for Neuroregeneration, University of Rostock, Rostock, Germany.
A K
AK
Giese
Department of Cerebrovascular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
G B
GB
Boncoraglio
School of Nursing and Midwifery, University of Newcastle, Newcastle, NSW, Australia.
J M
JM
Maguire
Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.|Department of Medicine I, Ludwig-Maximilians-University Munich, Munich, Germany.|DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany.
M
M
Müller-Nurasyid
Research Unit of Molecular Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.|Institute of Epidemiology II, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.
C
C
Gieger
Department of Neurology, Mayo Clinic, Jacksonville, FL, USA.
J F
JF
Meschia
Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.|Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
J
J
Rosand
Albrecht-Kossel-Institute for Neuroregeneration, University of Rostock, Rostock, Germany.
A
A
Rolfs
Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA.|Department of Neurology, Veterans Affairs Maryland Health Care System, Baltimore, MD, USA.
S J
SJ
Kittner
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.|Geriatric Research and Education Clinical Center, Veterans Affairs Maryland Health Care System, Baltimore, MD, USA.
B D
BD
Mitchell
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
J R
JR
O'Connell
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.|Research and Development Program, Veterans Affairs Maryland Health Care System, Baltimore, MD, USA.
Y C
YC
Cheng
D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D012306:Risk; D020521:Stroke / Q000453:epidemiology / Q000235:genetics*; D044465:White People / Q000235:genetics
heritability; ischemic stroke; stroke