Patterson-Stevenson-Fontaine syndrome

Patterson-Stevenson-Fontaine syndrome is inherited in an autosomal dominant manner.^[1][2] This means that having a change (mutation) in only one copy of the responsible gene in each cell is enough to cause features of the syndrome. The exact genetic cause of Patterson-Stevenson-Fontaine syndrome has not yet been identified, but that gene may be responsible for the correct development of the face and feet.

When a person with Patterson-Stevenson-Fontaine syndrome has children, each child has a 50% (1 in 2) chance to inherit the same gene change that causes the syndrome. However, Patterson-Stevenson-Fontaine syndrome reportedly shows reduced penetrance.^[1][2] This means that not every person with a disease-causing mutation will have features of the syndrome. Therefore, it is possible for this condition to appear to “skip” generations. If a person with the syndrome has a child with the gene change but no features of the syndrome, when this person goes on to have children, he or she may have features of the syndrome.  

Patterson-Stevenson-Fontaine syndrome also shows variable expressivity.^[2] This means that not all affected people will have the same signs and symptoms, and some people may be more severely affected than others.

In some cases, a mutation that causes an autosomal dominant syndrome is inherited from a parent with the mutation. In other cases, autosomal dominant syndromes are due to new mutations that occur for the first time (de novo) in an affected person. 

The unavailability of genetic testing and the reduced penetrance reported in this condition make assessing risks to family members difficult.

The risk to family members (including future children) likely depends on several factors, and because there is currently not a genetic test for the condition, finding answers to important questions may be hard.

Your risk to have the disease-causing mutation yourself may depend on the genetic status of your parents. If one of your parents is affected or has the mutation, your risk to have inherited that mutation is 50% (1 in 2). If you did inherit the mutation, each of your children then has a 50% risk to inherit the mutation. If you didn't inherit the mutation, it is no longer present and cannot be passed to your children.

If neither of your parents has the mutation and your brother is affected due to having a new (de novo) mutation, it is likely that your risk to have the disease-causing mutation is very low.

In addition to evaluating overall growth and development, prenatal ultrasound exams can be used to evaluate the fetal face and limbs. A detailed ultrasound may be able to detect or rule out the presence of features of this condition.

We strongly encourage you to meet with a prenatal genetic counselor or other genetics professional to discuss your family history and obtain more detailed information. We also recommend that you discuss your concerns and options for ultrasound screening with your prenatal care provider.

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.