Background
Author | Year | Race | Source of control | Method | Polymorphism sites | Characteristics of study patients | Case/control counts | HWE (Control) |
---|---|---|---|---|---|---|---|---|
Meng [19] | 2013 | Asian | PB | PCR-RFLP | rs2234693, rs9340799, rs1256049, rs4986938 | Age: 25–38 years (mean age 32.1 ± 5.2 years). Exclusion criteria: abnormal karyotypes, deletions of the Y chromosome, orchitis, varicocele, cryptorchidism, congenital bilateral absence of the vas deferens, hypogonadotropic hypogonadism, and iatrogenic infertility. | TT:83/82, CT:96/126, CC:25/44; AA:151/148, AG:42/89,GG:11/15; GG:103/127, AG:91/102, AA:10/23; GG:155/193, AG:41/48, AA:8/11 | 0.712, 0.793, 0.699, 0.001 |
Zalata [5] | 2013 | Caucasian | PB | PCR-RFLP | rs2234693, rs9340799 | Inclusion criteria: same ethnic origin (Caucasians). Exclusion criteria: varicocele, hormonal therapy, hypogonadism, smoking, Y chromosome deletions and karyotype abnormalities. The ages of were not shown in the article. | TT:33/14, CT:32/27, CC:16/19; AA:28/8, AG:36/32, GG: 17/20 | 0.468, 0.389 |
Ogata [20] | 2012 | Asian | PB | PCR-RFLP | rs1256049 | Age: 32–52 years (median 41.0 years). Inclusion criteria: no extragenital anomalies, seminal tract obstruction, varicocele, Y chromosomal microdeletion, or retrograde ejaculation; normal karyotypes. | GG:68/64, AG:49/45, AA:8/10 | 0.604 |
Bianco [7] | 2011 | Caucasian | PB | TaqMan assays | rs2234693, rs9340799, rs1256049, rs4986938 | Age: 36.1 ± 6.5 years. Exclusion criteria: chromosome anomalies, azoospermia factor (AZF) microdeletions, smoking, alcoholism, occupation, varicocele, and cryptorchidism. | TT:30/37, CT:93/111, CC:64/68; AA:80/100, AG:79/88, GG:20/28; GG:172/201, AG:15/15, AA:0/0; GG:43/28, AG:60/103, AA:84/85 | 0.468, 0.221, 0.597, 0.712 |
Safarinejad [21] | 2010 | Asian | PB | PCR-RFLP | rs2234693, rs9340799, rs1256049, rs4986938 | Age: 31.6 ± 4.8 years (range 25–40 years). Inclusion criterion: two years with no reason for their infertility. Exclusion criteria: varicocele or testicular torsion, urinary tract infections, endocrinopathy, karyotype anomalies, Y-chromosome microdeletions, use of drugs, leukocytospermia, a BMI of 30 kg/m2 or greater. | TT:49/33, CT:70/86, CC:45/45; AA:62/41, AG:77/95, GG:25/28; GG:142/152, AG:21/8, AA:1/4; GG:65/80, AG:82/63, AA:17/21 | 0.486, 0.034, 0.000, 0.132 |
Lazaros [22] | 2010 | Caucasian | PB | PCR-RFLP | rs2234693, rs9340799, rs1256049, rs4986938 | Age: 33.2 ± 67.5 years. Exclusion criteria: hypogonadotropic hypogonadism, obstructive syndromes of the seminal tract, microdeletions of the Y chromosome, karyotypic abnormalities. | TT:6/20, CT:14/40, CC:9/25; AA:5/13, AG:13/43, GG:11/29; GG:26/80, AG:3/5, AA:0/0; GG:7/17, AG:12/36, AA:10/32 | 0.609, 0.652, 0.779, 0.246 |
Khattri [23] | 2007 | Asian | PB | PCR-RFLP | rs1256049 | Age: 23.24 ± 2.06 years. Exclusion criteria: obstruction, endocrinological defect, injuries, karyotypic abnormality, Y-chromosome microdeletions. | GG:397/231, AG:46/21, AA:0/0 | 0.490 |
Omrani [24] | 2005 | Asian | PB | PCR-RFLP | rs1256049, rs4986938 | Exclusion criteria: genetic causes of infertility, such as Klinefelter syndrome or Ychromosome microdeletions. The ages of patients were no shown in the article. | GG:103/194, AG:17/9, AA:0/1; GG:51/86, AG:57/88,AA:12/30 | 0.023, 0.339 |
Aschim [25] | 2005 | Caucasian | PB | PCR-RFLP | rs1256049, rs4986938 | Exclusion criteria: Klinefelter syndrome or Y-chromosome microdeletions, a history of cryptorchidism were excluded. The ages of patients were no shown in the article. | GG:92/177, AG:14/8, AA:0/1; GG:11/82, AG:48/79, AA:47/25 | 0.015, 0.394 |
Kukuvitis [26] | 2002 | Caucasian | PB | PCR-RFLP | rs2234693, rs9340799 | Exclusion criteria: any known aetiologies (varicocele, infections of accessory glands, cryptorchidism, homozygous form of β-thalassemia). The ages of patients were no shown in the article. | TT:38/18, CT:38/25, CC:33/21; AA:30/10, AG:45/28, GG:34/26 | 0.083, 0.594 |
Methods
Identification and eligibility of studies
Data extraction
Statistical analysis
Results
Characteristics of studies
Quantitative synthesis
Category | Cases/controls | CC vs. TT | CT vs. TT | CC + CT vs. TT | CC vs. CT + TT | C allele vs. T allele | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| ||
Total | 774/841 |
0.72(0.54-0.96)
| 0.282 | 20.1 |
0.74(0.58-0.94)
| 0.533 | 0 |
0.73(0.58-0.91)
| 0.368 | 7.5 | 0.90(0.71-1.13) | 0.465 | 0 | 0.84(0.71-1.01) | 0.190 | 32.8 |
RACE
| ||||||||||||||||
Asian | 368/416 |
0.61(0.40-0.93)
| 0.670 | 0 |
0.67(0.49-0.93)
| 0.358 | 0 |
0.66(0.49-0.89)
| 0.593 | 0 | 0.83(0.58-1.18) | 0.257 | 22.1 |
0.78(0.64-0.96)
| 0.681 | 0 |
Caucasian | 406/425 | 0.83(0.46-1.23) | 0.175 | 39.5 | 0.83(0.57-1.19) | 0.460 | 0 | 0.81(0.58-1.14) | 0.232 | 30 | 0.95(0.70-1.29) | 0.395 | 0 | 0.87(0.64-1.18) | 0.103 | 51.5 |
Category | Cases/controls | AA vs. GG | GA vs. GG | AA + GA vs. GG | AA vs. GA + GG | A allele vs. G allele | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| ||
Total | 774/841 |
1.67(1.21-2.32)
| 0.392 | 3.9 | 1.03(0.76-1.39) | 0.764 | 0 | 1.27(0.96-1.68) | 0.796 | 0 |
1.63(1.32-2.03)
| 0.077 | 49.7 |
1.39(1.13-1.68)
| 0.172 | 35.3 |
RACE
| ||||||||||||||||
Asian | 368/416 | 1.56(0.93-2.62) | 0.714 | 0 | 0.81(0.49-1.34) | 0.524 | 0 | 1.13(0.71-1.82) | 0.952 | 0 |
1.93(1.42-2.62)
| 0.768 | 0 |
1.49(1.18-1.86)
| 0.375 | 0 |
Caucasian | 406/425 |
1.75(1.15-2.68)
| 0.174 | 39.7 | 1.17(0.81-1.71) | 0.847 | 0 | 1.35(0.95-1.92) | 0.569 | 0 |
1.38(1.02-1.88)
| 0.062 | 59.2 | 1.39(0.97-1.81) | 0.109 | 50.5 |
Category | Cases/Controls | AA vs. GG | GA vs. GG | AA + GA vs. GG | AA vs. GA + GG | A allele vs. G allele | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| OR(95% CI) |
P
a
|
I
2
| ||
Total | 1378/1478 | 0.57(0.32-1.01) | 0.940 | 0 |
1.59(1.12-2.25)
b
|
0.047
| 50.9 |
1.30(1.05-1.61)
| 0.075 | 45.7 |
0.55(0.32-0.96)
| 0.920 | 0 | 1.29(0.97-1.72) | 0.068 | 46.9 |
RACE
| ||||||||||||||||
Asian | 1056/991 | 0.57(0.32-1.01) | 0.853 | 0 |
1.52(1.00-2.31)
b
|
0.038
| 60.6 | 1.23(0.98-1.56) | 0.064 | 55 |
0.55(0.31-0.97)
| 0.818 | 0 | 1.19(0.86-1.65) | 0.067 | 54.4 |
Caucasian | 322/487 | 0.64(0.03-15.86) | - | - | 1.87(0.92-3.80) | 0.208 | 36.2 |
1.74(1.03-2.94)
| 0.275 | 22.6 | 0.58(0.02-14.38) | - | - | 1.66(0.99-2.77) | 0.372 | 0 |