She called her mother. What did birth-control pills do to you? she asked. It was terrible, her mother told her, and it took months to figure out. The first attack was just days before her wedding. She started on birth-control pills weeks earlier so she wouldn’t have to worry about becoming pregnant on the honeymoon. One morning she woke with terrible abdominal pain. Her father had to carry her to the car to rush her to the hospital. Doctors there couldn’t find anything wrong. She began to feel better a day later. But it happened again and again, and no one could figure out what was going on.
After months of these attacks, she realized they started after she went on the pill, so she stopped taking it. And miraculously, the pain stopped. Recently, her mother added, the patient’s cousin had the same kind of pain after she started taking the pill. So maybe it does run in the family.
Another Blind Alley
The patient told all this to Budhraja’s partner, who was caring for her during this hospitalization. It was a compelling story, the doctor agreed. She ordered the test for HAE, warning the patient it could take days to come back. In the meantime, they could help her with the pain and make sure nothing else was going on.
HAE is an inherited imbalance in the complex chemical systems that control swelling and inflammation. Most patients with HAE make insufficient or ineffective amounts of C1, a protein that blocks swelling and inflammation. If the patient has too little C1, it’s HAE type 1. If sufficient C1 is present but not working, the patient has HAE type 2. The patient went home the following day, after the pain resolved, excited to have found the cause of her pain. But when Budhraja saw the results of her test, he was surprised. Her C1 was totally normal. If she didn’t have HAE, what did she have?
Rare Variant of a Rare Disease
Budhraja quickly turned to an online medical resource called UpToDate. In the article on HAE, there was a single paragraph titled “HAE with normal C1.” Budhraja was relieved to see that such a thing existed. New research, he read, showed that there are many genetic abnormalities that can cause HAE, and while most involve C1, others do not. The most common of these rarities primarily affects women, usually causes swelling of the intestines and is often triggered by exposure to estrogen during pregnancy or after starting birth-control pills. The doctor couldn’t believe his luck. This newly described disorder, HAE 3, seemed to fit his patient and her family precisely.
Most patients with this rare variant of this rare disease have an abnormality in the gene that makes Factor XII, a part of the machinery that causes blood to clot. Exactly how this defect causes the swelling is still unclear. And the only way to test for it is to look at the gene that codes for the Factor XII protein. It was another six weeks before that answer came back: She had HAE 3. And so did one of her daughters, and probably her mother.
There’s no cure for this disease, but there are medications that can stop an attack once it has started. The patient now has this medication — just in case. She has dug deeper into her family background and thinks that many of the women on her mother’s side had this disease, and some may have died from it. She’s grateful to Budhraja for making this diagnosis. The doctor sees it differently. “I would love to take credit for this,” he told me. “Really I would. But it was the patient — she’s the one who did it.”