How Is Fabry Disease Inherited From a Father?

Fabry disease is passed down through families in a pattern called X-linked inheritance ^[1]. This means the gene responsible for the condition, the GLA gene, is located on the X chromosome ^[2][1].

To understand how a father passes Fabry disease to his children, it helps to look at the sex chromosomes that determine a child’s biological sex:

• Biological females typically have two X chromosomes (XX).
• Biological males typically have one X and one Y chromosome (XY).

When a man has a child, he passes on either his X chromosome or his Y chromosome. This single difference determines whether he will pass on the genetic mutation for Fabry disease. Learning exactly how this works can be an emotional blow, especially when considering the risks to future or current children, but knowing the facts is the best way to protect your family’s health.

Inheriting from a Father

If you are a man with Fabry disease, you have the mutation on your only X chromosome. Your Y chromosome does not carry the gene for Fabry disease. This leads to very specific, predictable rules for your biological children (assuming their mother does not also carry a Fabry mutation):

• Sons (0% chance of inheriting the gene): To have a biological son, you must pass on your Y chromosome. Because your Y chromosome does not carry the Fabry mutation, none of your biological sons will inherit Fabry disease from you ^[1].
• Daughters (100% chance of inheriting the gene): To have a biological daughter, you must pass on your X chromosome. Because your only X chromosome has the Fabry mutation, all of your biological daughters will inherit the gene for Fabry disease ^[1].

A Note for Daughters

In the past, women who inherited the Fabry disease gene were often called “carriers,” which made it sound like they would not experience symptoms. We now know this is incorrect. Because of a process called X-chromosome inactivation, the severity of Fabry disease in females can vary from person to person ^[1].

However, daughters who inherit the GLA gene mutation can and often do develop significant symptoms. These may include nerve pain in the hands and feet (which can sometimes start in childhood), as well as kidney and heart problems later in life ^[1]. Because cardiac and kidney issues are a major risk, daughters with the mutation need regular, routine monitoring by a medical team.

Genetic Counseling and Family Planning

Understanding these risks can feel overwhelming. Meeting with a genetic counselor—a professional trained to explain genetic conditions and help families navigate testing—is a critical next step. A counselor can help you with:

• Testing Current Children: If you already have daughters, a counselor can guide you on the best timeline for genetic testing, whether that is during childhood or waiting until they are older or show symptoms.
• Having Future Children: If you are planning to have more children and want to avoid passing the gene to a daughter, there are reproductive options available. For example, In Vitro Fertilization (IVF) can be combined with Preimplantation Genetic Testing (PGT) to screen embryos for the Fabry mutation before pregnancy.