personal story

My sister's diagnosis: Grappling with lupus' genetic link

Lupus Foundation of America

Resource Content

Jacklyn Cantu didn’t even know what lupus was.

Her symptoms started when she was 20 years old and working as a front office coordinator for a temp agency in San Antonio. By the end of her workdays, she’d have to go home and elevate her feet because they were so swollen. Months later, the swelling had progressed to pain all over her body.

Then one night, while she and her boyfriend were waiting outside a dance club, the swelling got so bad that he had to carry her back to the car. Her parents sent for her to come back home to Bryan, TX, where she was diagnosed with lupus. By then, she couldn’t walk, and her hands were so swollen that she could barely make a fist. Her parents, her younger sister, Jeannette, and her two younger brothers had to help her get dressed.

After nearly a year of being bedridden and accumulating $15,000 in medical bills, Jacklyn was finally put on the right regimen of medications, and her health gradually improved.

“My sister was there and had seen me at my worst,” recalls Jacklyn, now 28 and working as a human resources associate for the county she lives in. “What helped me get through it was thinking, ‘Thank goodness it’s me, and not my sister.’”

But that would soon change.

In early 2012, when Jeannette was 20, she casually told Jacklyn about vague aches and pains. “Then, one day she mentioned how she had to stop wearing her rings because her fingers were swelling,” Jacklyn recalls. That was a red flag.

Jacklyn made her sister go to the same doctor she’d seen for testing. “When the doctor diagnosed Jeannette with lupus, I cried,” Jacklyn says. “I was more devastated than she was.” Fortunately, Jacklyn was able to give her sister explicit “do this, not that” directions about lifestyle adjustments and medication side effects.

“I think my family was scared when I was diagnosed because we didn’t know what was going on,” Jacklyn says. “But they took my sister’s diagnosis easier because they saw that I had gotten to a good place.”

The inherited risk of lupus among sisters

Despite the mystery about what causes lupus, the disease appears to have a strong genetic link—particularly among siblings.

“If you have a sibling with lupus, then you have a genetic tendency that you’ve possibly both inherited,” says Amr Sawalha, MD, associate professor of internal medicine in the Division of Rheumatology at the University of Michigan in Ann Arbor. “That explains why lupus tends to cluster in families, and why having a sibling with lupus will increase your likelihood of developing it.”

But, unlike other genetic conditions that are linked to one gene, lupus has been linked to many genetic variants. Even if you have an identical twin with lupus, your chances of developing lupus are only about 30 percent, Sawalha says. For siblings who aren’t identical twins, the chance is much lower—between 2 and 4 percent.

And sisters who develop lupus don’t always have a parent with lupus. “Maybe your mother has half the risk, and your father has half the risk, but you developed the full risk,” Sawalha explains. “And if you have a family member with one autoimmune disease, that could make you more likely to develop another autoimmune disease.”

Jacklyn and Jeannette have not discovered any other family members diagnosed with lupus. But Jacklyn says both their maternal and paternal grandmothers had rheumatoid arthritis, another systemic autoimmune disease.

Being a female sibling also increases the chance of developing lupus, since the disease is nine times more common in women than in men, Sawalha says. 

Even though sisters with lupus may respond differently to treatments and have different triggers and disease manifestations, Sawalha agrees that the support they can offer each other can help with coping.

Jacklyn and Jeannette not only see the same rheumatologist, but they also make a day of doctors’ appointments, with lunch and shopping. “We like to hear what the doctor has to say about each other,” Jacklyn says.

Sisters help each other cope

For some sisters with lupus, their relationship is just as much about companionship as it is about coaching. Shelley Joyner, 47, of New Haven, CT, was diagnosed with lupus after nearly a year of unexplained hair loss and fatigue.

Soon after, her symptoms worsened to include joint pain and shortness of breath. “I couldn’t take a load of clothes from the washing machine to the dryer without huffing and puffing,” Shelley recalls. After being diagnosed with lupus, doctors discovered two blood clots on her lungs, and she had to be hospitalized. Later that same year, she developed uterine fibroids. The ablation surgery to remove the fibroids turned out to be the next nightmare: Shelley hemorrhaged so badly that doctors didn’t think she would make it. Unable to return to her job as an auto insurance claim analyst, Shelley applied for Social Security disability benefits, which she is now receiving.

A year later, her paternal half-sister, Erin, was suddenly diagnosed with renal failure. Doctors soon discovered that lupus was the culprit.

“Erin will call me when she’s going through a lot of things that I’ve already gone through,” Shelley says.

That’s because they understand each other in ways that their other siblings and family members can’t. “The thing we get the most is, ‘Wow, you look so good. You don’t look like anything is wrong,’” Shelley says. “But Erin understands when I’m having an achy day. We talk each other through how we’re feeling.”

Shelley urges her sister to pay attention to her body and not to let anyone tell her that her pain isn’t real. When one sister has to go to the hospital, the other steps up to babysit. They’ve even bumped into each other at the hospital—one was being wheeled in for a colonoscopy while the other was being wheeled out.

They’ve coached each other through depression, the process to obtain disability benefits, and choosing the right doctors.

“We go to church and pray a lot, and we ask people to pray for us,” Shelley says. “But we try to be self-sufficient. Even if it’s a bad day, we try to put that left foot forward. We know we can depend on each other.” 

3 common lupus myths among sisters

Myth 1: If my sister has lupus, I’ll probably develop it, too.

Sisters don’t inherit exactly the same genetic makeup, even though they have the same parents. Just as one can have dark hair and the other may be blonde, one sister can have more of the genetic variants that increase the risk of lupus. Also, even sisters who grow up in the same household may have different responses to the environmental triggers that lead to a lupus flare, such as sunlight, stress, and infections.

Myth 2: Sisters inherit lupus from their mother’s side of the family.

Women are more likely than men to develop lupus, but that doesn’t mean the genetic risk comes only from your mother. Fathers also can pass on the genetic variants that increase the risk of lupus. It’s just that having two X chromosomes raises the risk of actually developing the disease, says John Harley, MD, PhD, professor of medicine and pediatrics at the University of Cincinnati and director of the Center of Autoimmune Genomics and Etiology at Cincinnati Children’s Hospital Medical Center.

Myth 3: If my sister is diagnosed with lupus, I should probably get tested.

First, talk to your doctor about whether you’re having any symptoms, such as bone and joint pain, says Harley. If you’re not experiencing any symptoms, your doctor may tell you not to worry. Other doctors may advise having the tests just to make sure. “This really depends on your doctor, your personality, and how worried you are,” Harley says. Just remember: There is no single test for lupus.