Experts Review Benefits, Challenges of Family Genetic Testing

Family genetic testing can help to diagnose people with rare genetic conditions like Fabry disease, but there still are several barriers to implementing family genetic testing worldwide, according to an international panel of researchers who are using their experiences to share strategies for improving such testing.

The review, “The benefits and challenges of family genetic testing in rare genetic diseases—lessons from Fabry disease,” was published in Molecular Genetics & Genomic Medicine.

Fabry disease is caused by mutations in the GLA gene, which is located on the X chromosome. An early diagnosis of Fabry disease can allow for better clinical observation, earlier treatment and, ultimately, better health-related outcomes. Because of this, in recent years there have been efforts to implement programs to screen for Fabry-causing mutations in newborns and certain at-risk populations.

Like other genetic diseases, Fabry disease can run in families, since parents can pass the mutated gene to their children. The basic idea of family genetic testing is that if one person in a family is diagnosed with Fabry disease, their biological relatives should undergo genetic testing for the disease-causing mutation. In genetics, the first person in a family who is diagnosed with a genetic condition is called the “proband.”

The International Fabry Family Screening Advisory Board — a group of 19 experts in Fabry disease from 15 countries across four continents — conducted a review of the available literature on family genetic testing for Fabry disease.

The team reviewed 89 published studies. These studies identified a total of 365 probands, and 1,744 additional affected family members were identified through family genetic testing, which works out to nearly five additional diagnoses for each proband, on average. Notably, while most of the probands were male, 65% of the family members identified were female.

“This literature review suggests that family genetic testing used in combination with newborn screening or screening of at-risk populations … can lead to the identification of several additional family members with Fabry disease,” the researchers concluded.

“Family screening for rare genetic diseases can be highly effective, but the logistics and economics of its implementation are complex,” they added. “Moreover, there are numerous geographic, environmental, societal, and cultural barriers that limit the adoption of pedigree analysis and family genetic screening throughout the different regions of the world.”

The researchers summarized some of these barriers. Many barriers relate to cost — of testing itself, as well as specialist care and related infrastructure. The team noted that even though screening can be costly, it also can help to prevent future medical problems that are even more expensive to manage.

Logistical barriers, such as difficulty transporting samples and accessing people in remote areas, were noted. The team also said that increased accessibility and education could help make family testing more available.

Several potential cultural barriers were noted. For example, in some communities, it may be commonplace for one person to have multiple biological children with multiple partners, which can complicate the logistics of family genetic testing.

In many cultures, there is stigma associated with genetic diseases that may make people wary of testing.

“Because of possible stigmatization, it is necessary to emphasize data privacy when communicating with patients and their family members, and to carefully choose methods of communication for maximum discretion,” the researchers wrote.

The researchers also shared stories from their own experiences implementing family genetic testing for Fabry disease in their communities. For example, in Columbia, a collaboration with the pharmaceutical industry allowed a dedicated physician to be available to help in diagnosis and screening. In Argentina, meanwhile, people with Fabry disease play a key role as advocates for genetic testing.

“Patients are an essential part of the family screening process for Fabry disease in Argentina, and are utilized both as advocates within their family for genetic testing and as a source of new information. … The Argentinian experience highlights the vital role of patients in family screening,” the researchers wrote.

Meanwhile, they advocate for initiatives that may help improve the use of genetic testing in Fabry disease, such as “programs focused on educating physicians via presentations … with live questions and answers, design of simpler software tools to help draw digital family trees, and creation of patient educational booklets or online tools” for better communication, they wrote.