Who Gets Hemophilia?

Introduction

Jean Smith, a 27-year-old woman, is thinking about starting a family. But she is concerned because her brother and a cousin have hemophilia A.

John Jones and his wife have a son with hemophilia. The son wants to have children of his own. John wants to know whether his grandchildren will have hemophilia.

What do Jean and John have in common?

Both are facing questions and challenges related to genetics. Fortunately, families today can find more answers and solutions than ever before. Their journey may take them into uncharted territory, or it might follow a more traditional path. For most parents of a child with hemophilia, the journey begins when they discover the genetic nature of the disease. And for moms who learn that they can pass on hemophilia to their children, it’s an emotional first step.

“Moms often feel they’re to blame for their son’s condition, and I tell them it’s not their fault at all,” says Rachel Stuart, nurse coordinator at Phoenix Children’s Hospital Hemophilia Center in Arizona. “You don’t get to pick which genes you pass on—it’s a totally random roll of the dice.”

Marilyn Gradowski, hemophilia social worker at Phoenix Children’s Hospital, agrees. “Mothers often feel intensely guilty about this. These kinds of feelings are understandable—it’s normal to feel guilt, anger, and sadness. But they must be careful not to turn those feelings inward and become depressed.”

The remedy, says Gradowski, is education. “Get as much information as you can, talk to others who have been through it, or work through your feelings with an experienced social worker or counselor,” she says. “Usually, once people understand it’s not their fault, they can make good decisions. They can also help their child make good decisions about care and treatment.”

Genetic counselor Sarah Cox at the University of Arizona uses a blend of education and support to help families deal with a diagnosis of hemophilia. “I work with the HTC team to counsel women and help get them through the guilt. I tell mothers that their child’s hemophilia has nothing to do with anything they did or did not do during their pregnancy and that they have no control over it. I try to find out what their belief systems are, educate them about genetics, and introduce parents to others in the same situation.”

Cox also counsels parents who are considering having another child—a difficult decision for many couples, but an especially tough decision for those already dealing with a chronic condition like hemophilia. And the more severe the hemophilia, typically the more concerned the couple is about having another child, says Cox. To help, testing options are available today that didn’t exist even in the past decade.

If a couple already has a child with hemophilia, mutation testing is usually recommended. “This test identifies the mutation in the gene that is the cause of his hemophilia,” Cox explains. “It can be something that was passed down to him from his mother, or it can occur spontaneously at the time of his conception.” If a mutation is identified, then the mom is tested to determine if she carries this same mutation on one of her X chromosomes. If she does not have the mutation, it is unlikely for hemophilia to recur in subsequent offspring, says Cox.

With severe hemophilia A, Cox finds gene mutations 60 percent of the time in the affected child. In the remainder of cases, linkage analysis may be the next step to explore whether related females are carriers. “Linkage analysis, if applicable for a particular patient, can help us determine carrier status in inherited cases,” says Cox.

Carrier testing is another important assessment that geneticists use. If testing reveals a mutation in a male, his sisters, mother, and mother’s relatives can be tested if they are interested in knowing their carrier status. “There are a number of misconceptions about being a carrier,” says Cox. “Some people assume that because they resemble a relative with hemophilia, they must be carriers. In another family, the dad had hemophilia, but they were hopeful the daughters were not carriers. That is not genetically possible—the daughters are automatically carriers of the hemophilia gene mutation because they must receive their father’s X chromosome.”

But there are limitations to carrier testing, Cox cautions. “We can’t tell families with 100-percent certainty if they’re carriers; first we have to identify the mutation, and that’s not possible in each case.”

Cox recommends that known carriers also have factor-level testing (assessing the levels of Factor VIII in blood to identify deficiencies) to ensure that they don’t have bleeding issues themselves. It is important to know a mother’s factor level prior to becoming pregnant.

New Options, New Hope

“The hopeful part is that we have so many more options than we did even a few years ago,” says Gradowski. “Women don’t have to give up and say ‘I’m a carrier and there’s nothing I can do.’”

Those options include choosing to remain childless, adopting a child, being tested during pregnancy to determine whether the child is affected, and the very latest technique called pre-implantation genetic diagnosis.

“First, in vitro fertilization techniques are used to harvest eggs and fertilize them with the father’s sperm,” Cox explains. “When the embryo reaches the eight-cell stage, a single cell is removed for genetic testing. They then implant only the non-affected embryos, or—as another option—only implant the female embryos.”

Of course, the most common option is to start a family without taking special steps to avoid having a child with hemophilia. Many parents decide to have children knowing that the child might have hemophilia, but also knowing that they will love the child with or without hemophilia. However, genetic testing can still help prepare these new parents for the diagnosis of hemophilia—if the child does inherit the disease—and discover whether the mother has low factor levels herself. The information also can help the family’s health-care provider prepare for the safe delivery of the child and for the appropriate care immediately following birth.

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