Preimplantation Genetic Diagnosis (PGD) for XLH
If you have a rare genetic disease such as X-linked hypophosphatemia (XLH), the thought of having children with a similar disorder may be stressful. Preimplantation genetic diagnosis (PGD) is a fertility procedure that may allow you to have children without XLH.
What is XLH?
XLH is a rare genetic disorder passed on through the X chromosome. It is inherited in a dominant pattern meaning that only one copy of the faulty gene is sufficient to cause the disorder. Because of this, XLH can occur in both men and women. Mutations in the PHEX gene that contains the information necessary for cells to make an enzyme called phosphate regulating endopeptidase homolog X-linked (PHEX) cause the disease.
Researchers think this enzyme plays a role in regulating the reabsorption of phosphate in the kidneys. The mutation results in a reduction in working PHEX enzymes. This ultimately leads to lower amounts of phosphate available in the body. Phosphate is an important mineral required for the development and growth of bones and teeth. That is why patients with XLH develop symptoms such as bone abnormalities and teeth problems.
What is PGD?
PGD is the process of taking samples of cells from embryos and testing them for genetic disorders such as XLH before implanting them in the mother’s uterus. Patients first undergo in vitro fertilization (IVF) for which a doctor will extract eggs from the mother and combine them in a laboratory with sperm from the father before implanting them into the uterus of the mother or a surrogate. In PGD, clinicians can test the embryos for multiple genetic disorders, including XLH. Doctors then can implant the embryos without the genetic disorder.
Benefits of PGD
If one or both parents have XLH, PGD offers the opportunity to have a child without the disorder.
If the father has XLH he will pass the disease to all his daughters, but none of his sons. That is because males inherit the X chromosome from their mothers and their Y chromosome from their fathers. Females inherit an X chromosome from both parents. If the mother has XLH, then all of her children have a 50% chance of inheriting the disease. This will depend on which X chromosome they receive from her. If both parents have the disorder then any daughters will have the disease and any sons will have a 50% chance of inheriting it.
By being able to screen for multiple genetic disorders, parents can decide whether they want to continue with the IVF pregnancy.
Other concerns with PGD
While PGD can greatly reduce the risk of having a child with a genetic disorder, some mutations can happen during development, which has the potential to cause health problems. Because of this, you may still want to consider prenatal testing.
The embryos not used in the IVF process usually are destroyed, which may raise ethical concerns for some people.
Last updated: Sept. 11, 2020
XLH News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.