No observed association for mitochondrial SNPs with preterm delivery and related outcomes.
BACKGROUND
Preterm delivery (PTD) is the leading cause of neonatal morbidity and mortality. Epidemiologic studies indicate recurrence of PTD is maternally inherited, creating a strong possibility that mitochondrial variants contribute to its etiology. This study examines the association between mitochondrial genotypes and PTD and related outcomes.


METHODS
This study combined, through meta-analysis, two case-control, genome-wide association studies: one from the Danish National Birth Cohort Study and one from the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. The outcomes of PTD (≤36 wk), very PTD (≤32 wk), and preterm prelabor rupture of membranes (PPROM) were examined. A total of 135 individual single-nucleotide polymorphism (SNP) associations were tested using the combined genome from mothers and neonates (case vs. control) in each population and then pooled via meta-analysis.


RESULTS
After meta-analysis, there were four SNPs for the outcome of PTD below P ≤ 0.10 and two below P ≤ 0.05. For the additional outcomes of very PTD and PPROM, there were three and four SNPs, respectively, below P ≤ 0.10.


CONCLUSIONS
Given the number of tests, no single SNP reached study-wide significance (P = 0.0006). Our study does not support the hypothesis that mitochondrial genetics contributes to the maternal transmission of PTD and related outcomes.
Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA.
Brandon W
BW
Alleman
Solveig
S
Myking
Kelli K
KK
Ryckman
Ronny
R
Myhre
Eleanor
E
Feingold
Bjarke
B
Feenstra
Frank
F
Geller
Heather A
HA
Boyd
John R
JR
Shaffer
Qi
Q
Zhang
Ferdouse
F
Begum
David
D
Crosslin
Kim
K
Doheny
Elizabeth
E
Pugh
Aase Serine Devold
AS
Pay
Ingrid H G
IH
Ostensen
Nils-Halvdan
NH
Morken
Per
P
Magnus
Mary L
ML
Marazita
Bo
B
Jacobsson
Mads
M
Melbye
Jeffrey C
JC
Murray
D016022:Case-Control Studies; D016009:Chi-Square Distribution; D004272:DNA, Mitochondrial / Q000235:genetics*; D003718:Denmark; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D009664:Norway; D016017:Odds Ratio; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D047928:Premature Birth / Q000235:genetics*; D018570:Risk Assessment; D012307:Risk Factors
D004272:DNA, Mitochondrial