09 May 2011
ByAppeared in BioNews 606
A genetic predisposition towards autoimmune disease may be associated with lower pregnancy rates in IVF, a US study suggests. The findings offer a possible explanation for differences in IVF treatment outcomes between different ethnic groups.
Previous research has shown African patients have higher rates of FMR1 (Fragile X mental retardation) genotype, which is in turn associated with autoimmune disease and also lower IVF pregnancy success. African women also statistically have higher rates of infertility and are less likely to respond successfully to IVF treatment when compared to women of Asian or Caucasian descent - an observation that has puzzled scientists for many years.
'The association of FMR1 genotypes and risk for autoimmunity presents evidence that autoimmunity may be associated with lower pregnancy rates in IVF in general. Autoimmunity may, thus, also be at least partially responsible for the racial/ethnic disparities in infertility prevalence and treatment outcomes', said Professor Norbert Gleicher, Medical Director of the Center for Human Reproduction (CHR) in New York which carried out the research.
Previous research carried out by the CHR had identified the gene FMR1 as a possible predictor of IVF treatment success. Abnormalities in FMR1 are associated with autoimmune diseases and polycystic ovary-like syndromes. FMR1 naturally differs from one individual to the next but one particular sub-genotype has been previously linked to infertility.
The researchers compared this sub-genotype to IVF pregnancy rates of over 300 women from different ethnic groups. They found that it was most commonly identified in African women - who also encountered lower IVF success. Conversely, the lowest frequency of the sub-genotype was found in Asian women that in turn demonstrated the highest success rate for IVF treatment.
'This study confirms that African women experience lower IVF pregnancy rates than Caucasians and Asians', the researchers wrote, adding: 'These observations support FMR1 contributions to pregnancy outcome differences between races but do not yet allow us to accurately quantify these effects'.
The researchers said additional association studies on a large number of patients are required before FMR1 could become 'a clinically useful tool in accurately predicting odds of pregnancy in association with the IVF process'. However, they said: 'Changes in treatment protocols would, however, appear inappropriate, except in clinical trials, and with appropriate informed consents'.