Genetic aspects of female infertility

Abstract

Introduction. Female infertility is defined as the inability to conceive after one year of regular unprotected intercourse for women younger than 35 years and within 6 months for women after 35 years. One in seven couples experiences infertility or subfertility, and in 40% of cases it is because of women. Clinically, female infertility is a highly heterogeneous pathology with a complex etiology that includes environmental and genetic factors. It is difficult to assess accurately the overall magnitude of the contribution of the genetics to female infertility as most, if not all, conditions are likely to have a genetic component. Nethertheless, a significant number of infertility phenotypes have been associated with specific genetic anomalies. Aim of the study. - This review aims to summarize current research on genetic diagnosis and genetic causes of female infertility. Material and methods. It has been used online databases and scientific articles that contain studies of female infertility. Results. All genetic defects can be divided into the following categories: chromosome aberrations, DNA copy number variants (micro deletions and duplications), single-gene disorders, complex conditions and epigenetic disorders. Chromosome abnormalities account for almost 60% of all spontaneous abortions, and the most common type, trisomy, is closely associated with advanced maternal age. There are 2 forms of female infertility: primary and secondary. Primary female infertility includes premature ovarian failure, polycystic ovary syndrome, endometriosis, and leiomyoma. Secondary infertility arises due to systemic or syndromic genetic defects, including developmental, endocrine, and metabolic defects. Genetic syndromes that manifest female infertility are fragile X syndrome, Noonan syndrome, sickle cell anemia, etc. Other notable conditions include disorders of sex development (SRY), reproductive dysgenesis disorders hypogonadotropic hypogonadism and Kallmann syndrome (KAl1, GNRH1, LEP) , and ambiguous genitalia an androgen insensitivity (AR). Endocrine defects comprise disruption of steroid synthesis and metabolism, and are caused by CYP17 and CYP19 mutation. Also, various metabolic defects (e.g., galactosemia ) and mutation in mitochondrial energy pathway (mitochondrial DNA genes) cause toxic effects and lead to secondary female infertility. Conclusions. The genetics of infertility is very complex and is dependent on different factors. Clearly the hope is that a greater understanding of the genetic control of infertility will bring low-risk treatment regimens that are effective and easy to administer.