A few weeks after a 9-year-old girl twisted her ankle, she suddenly started screaming and crying about severe foot pain. However, her foot "looked completely normal," and doctors could not identify the cause of her mysterious pain – until her hand movements led doctors to test for a rare movement disorder, Lisa Sanders writes for the New York Times Magazine.

Her foot 'looked completely normal'

After being uncharacteristically quiet at a family dinner, the 9-year-old girl suddenly started screaming, crying, and pointing to her foot. Her family immediately rushed her to the ED near their Miami Beach hotel.

When they arrived at the ED, the girl's foot was still in too much pain to walk on. Once they were in the exam room, her father was finally able to examine his daughter's foot. "He was surprised," Sanders writes. "It looked completely normal."

The doctor in the ED X-rayed the girl's foot, said that everything seemed normal, and told them to follow up with her doctor if the pain persisted.

However, that incident was only the beginning. After they returned to their home in New York City, the girl complained about her ankle and foot almost every day, saying that running hurt too much.

Over the past few years, the girl had sprained the same ankle several times. Her doctors attributed this to weak ligaments and a sports-heavy schedule. However, this seemed different – her ankle never improved after that last injury.

In the coming months, she visited multiple orthopedists at the Hospital for Special Surgery. When one ordered an MRI of her ankle, the girl explained that while holding her foot in the correct position was painful, holding it still was nearly impossible. Ultimately, the MRI did not show any abnormalities.

Doctors tried physical therapy, cortisone shots, and an ankle brace, but they were all unsuccessful.

'Has anyone mentioned something called dystonia to you?'

Then, feeling "a sense of desperation," her father reached out to Joshua Hyman, an old friend who was now a pediatric orthopedic surgeon at NewYork-Presbyterian Morgan Stanley Children's Hospital, Sanders writes.

When he described his daughter's pain and stiffness, Hyman asked if he was able to put it the girl's foot in a more normal position. While he could do this, he noted that it felt like the foot was not cooperating. As soon as he released his hold, her foot would slowly revert to its side.

"Has anyone mentioned something called dystonia to you?" Hyman asked

Dystonia is a movement disorder that causes persistent or intermittent muscle contractions, which often trigger abnormal, repetitive movements or positions, Hyman said.

It can impact any part of the body – sometimes even the entire body. "It's a problem with the brain and the nerves," Sanders writes. "They send the wrong message to the muscles."

According to Hyman, there are a lot of possible causes, including medications, infections, brain injuries, and a few inherited diseases. He explained that the girl needed to see a neurologist that specializes in movement disorders.

In late spring, the family took the girl to see Steven Frucht, director of the Fresco Institute for Parkinson's and Movement Disorders at NYU Langone Health. He immediately noticed that the girl's feet were not symmetrical.

When Frucht asked the girl to put her feet flat on the floor, she could easily do so with her right foot, but her left foot seemed to curve inward, with just the outer edge of her foot resting on the ground. In addition, her big toe on her left foot constantly moved up and down while the toes on her right foot were still. "Why are your toes moving?" Frucht asked. "Because it's uncomfortable," the girl replied.

Frucht also asked if she had any issues with her hands. "Not really," she answered. "Except I always get cramps when I write."

Then, Frucht told the family he suspected the girl had a rare form of dystonia, which is the most common form of inherited limb dystonia among people of Ashkenazi Jewish descent. The condition, called DYT-TOR1A, was named for the abnormal gene in this disease.

"Whom could she have inherited it from?" the girl's father asked.

"Neither parent nor anyone in either family had this problem," Sanders writes. "It is one of the mysteries of this disease. Only one parent has to have the gene to pass it on. Yet most people with this abnormal gene never develop the disease."

A 'life-changing' surgery

To confirm the suspected diagnosis, Frucht ordered a test to look for the abnormality.

Roughly one week later, the test came back positive. Frucht started her on a drug called Artane, which works to block some of the brain's abnormal signals to the body.

"As the dose was increased, the girl and her parents could see the difference. Her walk wasn't completely normal, but it was much better — so much better that she was able to go to summer camp," Sanders writes.

However, she had to keep taking a higher and higher dose of the medication. By the fall, she was starting to experience side effects.

Since the disease is progressive, Frucht told the family about another kind of treatment called deep brain stimulation. While he did not recommend it for younger children, the girl eventually decided to have the operation.

"It took awhile, but the surgery has been life-changing. Or perhaps, the family would say, life-normalizing," Sanders writes. "Because she's back: She's back on the basketball court, back to her good grades. She still has her head of beautiful dark hair; and even the tiny patch that was shaved for the surgery is back." (Sanders, New York Times Magazine, 2/7)