How Your Family Tree Impacts Fertility
A family tree—or family history—represents all of someone's blood relatives, including their mom, dad, grandparents and great-grandparents. A family tree can also be thought of as someone's genetic history, or where they get their genes. Genes are passed down from parents to children and are responsible for many physical and behavioral traits. Knowing your genetic history is important because genes can be responsible for male and female infertility.
Genetic disorders affecting fertility
Genes have the potential to cause genetic abnormalities, genetic disorders and chromosomal abnormalities that can affect sperm production, embryo development and embryo implantation. In the United States, infertility rates are rising, and it's estimated 50 percent of infertility cases are related to genetic disorders. According to Brigham and Women's Hospital, there are two categories of genetic disorders affecting male and female fertility:
- Single gene defects where DNA is mutated or abnormal in some way. Examples include:
- Cystic fibrosis: Men with cystic fibrosis or cystic fibrosis transmembrane conductance regulator (CFTR) abnormalities may have trouble ejaculating, which can affect their fertility.
- Sickle cell disease: This inherited disorder affects male and female fertility by delaying sexual maturation and causing testicular and ovarian dysfunction.
- Spinal muscular atrophy: This genetic disease impairs testis development and can reduce sperm count, which leads to fertility problems.
- Chromosomal abnormalities where chromosomes, which carry DNA, change in structure or number. Examples include:
- Down syndrome: Women and men with Down syndrome have an extra chromosome and high rates of infertility. Women with Down syndrome have a 50 percent chance of having a child with Down syndrome.
- Klinefelter syndrome: This syndrome causes about 3 percent of male infertility cases and is caused by an extra X chromosome in men.
- Turner syndrome: This syndrome only affects females and happens because an X chromosome is fully or partially missing. It causes ovarian failure and infertility.
This list of genetic disorders and abnormalities is not comprehensive. For a complete list of genetic disorders that affect fertility, it's best to talk with a fertility specialist or geneticist.
Diagnosis of genetic disorders affecting fertility
Diagnosing someone with a genetic disorder can be difficult because there may be other factors causing their infertility, such as age, smoking, weight, sexual history or substance abuse. During an infertility evaluation, a doctor will ask their patient for their complete medical history and may recommend genetic testing if their patient is from a certain ethnic group. This is because certain ethnic groups have higher incidences of genetic disorders. Sickle cell disease, for example, is more common among African Americans and Tay Sachs disease is more common among French Canadians and Ashkenazi Jews.
Genetic testing can help determine whether or not someone has a genetic disorder that might be causing or contributing to their infertility. If and when a diagnosis is reached, it's much easier for doctors to devise a treatment plan to help someone start a family.
Treatment of genetic disorders affecting fertility
Treatment for genetic disorders that cause infertility is largely centered around in vitro fertilization (IVF), where an egg and sperm are combined outside the body. Once an egg has been fertilized outside the body, it's placed back into the uterus. Although male infertility genetic disorders can't be cured, men can have their sperm injected into an egg as part of an IVF treatment. Before implanting an egg back into a uterus, it's possible to have preimplantation genetic screening done on an embryo to check for genetic conditions that might get passed on from parent to child.
Infertility treatment options for people with genetic disorders or abnormalities may vary based on the specific condition they have. If you have a family history of infertility or are struggling with infertility, it may be a good idea to discuss your family tree with your OB-GYN or fertility doctor. Together, you can determine what's causing your infertility and begin treatment.