Table 5 Maternal genotypes at SNPs in iron-related genes and full scale IQ of their children at 8 years of age

From: Maternal iron levels early in pregnancy are not associated with offspring IQ score at age 8, findings from a Mendelian randomization study

dbSNP

Gene

Genotype

Full scale IQ

s.d

N

Unadjusteda effect (95% CI) P-value N

Adjustedab effect (95% CI) P-value N

rs1799945

HFE

GG

105.9

17.0

79

0.50 (–0.59, 1.58) 0.37 3543

1.09 (–0.27, 2.45) 0.39 2402

  

CG

102.9

16.3

850

  
  

CC

104.1

16.4

2614

  

rs1800562

HFE

AA

107.1

12.8

15

–0.52 (–2.05, 1.00) 0.50 3535

0.38 (–1.57, 2.32) 0.71 2352

  

GA

104.2

16.6

455

  
  

GG

103.8

16.5

3065

  

rs3811647

TF

GG

104.0

16.3

1511

–0.13 (–0.95, 0.69) 0.76 3514

–0.36 (–1.40, 0.68) 0.50 2378

  

GA

103.9

16.3

1613

  
  

AA

103.6

17.3

390

  

rs4820268

TMPRSS6

AA

104.3

16.0

962

–0.74 (–1.52, 0.05) 0.07 3527

–0.23 (–1.23, 0.77) 0.66 2389

  

AG

104.1

16.7

1837

  
  

GG

102.7

16.3

728

  

rs1799945/rs1800562

2 risk alleles

0

106.1

16.3

156

0.11 (–0.83, 1.05) 0.82 3490

0.99 (–0.19, 2.18) 0.10 2312

 

3 risk alleles

1

103.1

16.5

1163

  
 

4 risk alleles

2

104.0

16.4

2171

  

genotypic score

⩽3 risk alleles

0

103.8

16.1

464

–0.32 (–0.94, 0.30) 0.31 3444

0.22 (–0.54, 0.98) 0.57 2254

 

4 risk alleles

1

104.4

16.7

1143

  
 

5 risk alleles

2

103.5

16.1

1392

  
 

6 risk alleles

3

103.3

16.8

445

  
  1. aEffect=mean difference in offspring IQ per risk allele or unit increase in genetic score.
  2. bModel adjusted by iron supplementation, child’s genotype or score, maternal education and population stratification.
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