Table 12 Genes associated with the α-glutamyl cycle or trans-sulfation pathway

Glutathione-s- transferases

GST-M1

Buyske et al. 2006 [96]

172 controls (54 case parent trios)

U.S. (non-Hispanic Caucasians)

GST-M1

GST-M1*0

0.028 (Pearson's) 0.046(Likelihood ratio)

Homozygotes with deletion at increased risk.

James et al. 2006 [47]

360 cases 205 controls

U.S. (97% Caucasian)

GST-M1

GST-M1*0

0.067^1,2

Suggestive increase of null genotypes in cases.

Bowers et al. 2011 [94]

318 families (1,149 individuals)

U.S.

GST-M1

tag SNPs

ns

No association.

James et al. 2006 [47]

As above

As above

GST-M1 +

GST-M1*0: RFC

0.00014^1,2

This combination more frequent

RFC

80A > G interaction

in cases. OR 3.78(95%CI 1.80, 7.95).

GST-P1

Serajee et al. 2004 [97]

196 case parent trios

U.S.

GST-P1

rs947894

ns

Bowers et al. 2011 [94]

As above

GST-P1

tag SNPs

ns

GST-T1

James et al. 2006 [47]

As above

As above

GST-T1

GST-T1*0

ns²

Glutathione peroxidase

Ming et al. 2010 [95]

101 cases (results

U.S

GPx-1

GCG repeat

based on 68 trios

ALA5

ns

and 3 duos)

ALA6

0.017

Under-transmitted

ALA7

ns

Bowers et al. 2011 [94]

As above

As above

GPx-1

tag SNPs

ns

ALAD

Single SNP analysis

Rose et al. 2008 [50]

451 cases

U.S.

ALAD

rs1800435

0.023

GC OR 1.65 (1.05-2.63)

251 controls

0.6

CC OR 1.82 (0.14-95.73)

Interaction analysis

ALAD rs1800435*GC

ALAD/RFC GG/AA reference

RFC 80A > G combined

0.162

ALAD/RFC GC/AA OR 2.25 (0.72-7.06)

genotype associated with

0.001

ALAD/RFC GCAG OR 3.98 (1.70-9.32)

increased risk of autism.

0.237

ALAD/RFC GC/GG OR 1.79 (0.68-4.73)

Study

Study Size

Population

Gene

Polymorphism

P value

Finding

Other relevant genes

Single SNP analysis

Bowers et al. 2011 [94]

As above

CTH

rs12737233

0.002 (0.30)³

CT OR 0.91 (0.65-1.28)

(Validation study in 3327 individuals from independent

TT OR 4.83 (1.85-12.59)

AGRE families)

GCLC

rs761141

0.02 (0.10)³

CT OR 2.10 (1.20-3.69) TT OR 1.67 (0.91-3.09)

rs524553

0.003 (0.08)³

CT OR 2.70 (1.47-4.98)

TT OR 2.23 (1.16-4.28)

DPP-1

tag SNPs

ns

DPP-2

tag SNPs

ns

DPP-3

tag SNPs

ns

GGT-7

tag SNPs

ns

GGT-5

tag SNPs

ns

GGT-LA4

tag SNPs

ns

GPx-2

tag SNPs

ns

GPx-4

tag SNPs

ns

GPx-7

tag SNPs

ns

GST-A2

tag SNPs

ns

GST-A3

tag SNPs

ns

GST-A4

tag SNPs

ns

GST-K1

tag SNPs

ns

GST-M2

tag SNPs

ns

GST-M3

tag SNPs

ns

GST-M4

tag SNPs

ns

GST-M5

tag SNPs

ns

GST-O1

tag SNPs

ns

GST-T2

tag SNPs

ns

GST-Z1

tag SNPs

ns

GST-CD

tag SNPs

ns

Interaction analysis

CTH rs12737233*C

OR 3.78 (95%CI 2.36-6.04)

GLRX3 rs370834*A

GLRX rs17216887*G

allele combination associated

with increased risk of autism.