Fabry disease is not contagious. The faulty gene is usually passed on within biological families. Mutations in the GLA gene can also occur spontaneously, but are rare.
Because the GLA gene is on the X chromosome, Fabry disease is passed on by ‘X-linked inheritance’. Here is how X-linked inheritance works:
- Women have two X chromosomes (XX) and men have one X and one Y chromosome (XY). All children inherit one chromosome from each parent.
- Men (XY) only have one X chromosome to pass on to their children, and their daughters (XX) must inherit this chromosome. Therefore, a father with Fabry disease will pass the faulty gene on to each of his daughters.
- Women (XX) have two X chromosomes to pass on, and every child – boy (XY) or girl (XX) – could inherit either one of these. Therefore, each child of an affected mother has a 50% chance of inheriting the faulty gene.
If the father (XY) is affected: all daughters will be affected
If the mother (XX) is affected: every child has a 50% chance of being affected
To work out the risk of your relatives inheriting Fabry disease, a doctor will ask for your family’s medical history, and map out a family tree using symbols to represent genetic relationships: this is called family tree analysis.
A medical genetic counsellor can work to develop a medical family tree and establish who within the family is at risk.