Association of 14-bp insertion/deletion polymorphism of HLA-G gene with idiopathic recurrent miscarriages in infertility center patients in Yazd, Iran

Figures & data

Figure 1. Identified and non-identified causes for RM. Information adapted from Ford and Schust (2009).

Figure 2. Inhibitory receptors associated with HLA-G. Schematic illustrates how ILT2 and KIR2DL4/HLA-G interactions can lead to inhibition of NK-cell functions.

Figure 3. Detection of 14-bp deletion/insertion polymorphisms using electrophoresis. Lane 1: 50-bp ladder; lanes 2 and 5: homozygote for insertion; lanes 3 and 4: heterozygote; lane 6: homozygote for deletion. The figure shows a representative gel. Values to the right indicate the molecular weights of the PCR products (224 or 210 bp) depending on insertion or deletion of the 14 bp in exon 8.

Table 1. Clinical characteristics of patients with RM.

	n (%)
Number of miscarriages
2	29 (14.6%)
3	96 (48.0%)
4	55 (27.6%)
5	20 (9.8%)
Time of miscarriage during pregnancy (week)
1–5	83 (41.5%)
6–10	90 (45.0%)
11–15	22 (11.0%)
16–19	5 (2.5%)

Figure 4. Comparison of genotype frequencies in the context of total miscarriage number. For the three common genotypes, there were significantly more women with the heterozygous genotype that experienced 2–5 miscarriages. Values shown are mean ± SD. At any of the fixed number of miscarriages, all values in the heterozygous group were significantly (p < 0.05) greater than those in either heterozygous group. For n = 200 RM subjects; actual numbers of subjects with 2, 3, 4 or 5 events were, respectively, 30, 96, 55 and 19.

Table 2. Distribution of maternal 14-bp genotypes and alleles in control and study (RM) subjects.

	RM	Control	p value
In/del 14 bp
+14/+14
Count	24	31	0.384
% within group	12.0%	15.5%
+14/−14
Count	159	114	0.000
% within group	79.5%	57.0%
−14/−14
Count	17	55	0.000
% within group	8.5%	27.5%
Insertion allele
Count	183	145	0.000
% within group	91.5%	72.5%
Deletion allele
Count	176	169	0.182
% within group	88.0%	84.5%

Within each group, values significantly differ (p < 0.05). Between groups, values significantly differ (p < 0.05) for matching 14 bp status.

Values shown in table are based on n = 200 RM subjects and n = 200 controls.

Table 3. Comparison of distribution of maternal 14-bp genotypes in different ethnic RM populations.

Genotype	Chinese	Danish	Indian	Iranian
+14 bp/+14 bp	19 (17.4%)	31 (33.3%)	37 (30.8%)	24 (12.0%)
−14 bp/+14 bp	57 (52.2%)	52 (55.9%)	51 (42.5%)	159 (79.5%)
−14 bp/−14 bp	33 (30.4%)	10 (10.8%)	32 (26.7%)	17 (8.5%)
n (# RM subjects)	109	93	120	200

Results from the Chinese, Danish and Indian RM patients were derived from Yan et al. (2006).

Ford, H. B., and Schust, D. J. 2009. Recurrent pregnancy loss: Etiology, diagnosis, and therapy. Rev. Obstet. Gynecol. 2:76–83

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Yan, W. H., Lin, A., Chen, X., et al. 2006. Association of the maternal 14-bp insertion poly-morphism in the HLA-G gene in women with recurrent spontaneous abortions. Tissue Antigens 68:521–523

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