In a case that doctors have called "unbelievably rare," four sisters from West Virginia were diagnosed with the same brain and spinal condition known as Chiari malformation.

All four girls underwent surgical procedures in New York.

A family in West Virginia was left stunned after four of their daughters were diagnosed one after another with the same rare brain condition. Paul and Ashlee Higginbotham were first taken by surprise when their youngest daughter was diagnosed with Chiari malformation - a rare structural defect in the brain - at just 18 months old. What seemed like a one-off medical challenge soon turned into a devastating pattern, as four out of their six children were eventually found to have the same condition.

According to CBS News, the parents first grew concerned over their youngest daughter, Austyn, who as a baby was constantly fussy and not reaching developmental milestones. Her mother said Austyn was "never content... never smiling, never laughing."

At 18 months, an MRI revealed she had a Chiari malformation, a rare condition where part of the skull is too small or misshapen and crowds the brain, forcing the cerebellum down into the spinal canal. This can disrupt the flow of cerebrospinal fluid and press on nerves, causing various symptoms.

"That moment when Austyn's MRI results came up on my screen and we read the diagnosis of Chiari malformation – that was the moment our world was flipped upside down," Ashlee said.

Over the next two years, three of Austyn's older sisters, Amelia, Aubrey, and Adalee, were also diagnosed with the same condition, along with tethered spinal cords. A tethered spinal cord is an abnormality where the spinal cord becomes stretched, causing leg pain and other nerve issues.

All four girls underwent surgical procedures performed by pediatric neurosurgeon Dr. Jeffrey Greenfield at NewYork-Presbyterian Hospital. The surgeries aimed to decompress the brain and snip the tethered spinal cords, allowing for restored cerebrospinal fluid flow.

The surgeries successfully alleviated the girls' symptoms, though some experience minor, lingering pain. The two eldest children in the family were screened and do not have the condition.

What is Chiari malformation?

Chiari malformation is a condition where the lower part of the brain extends beyond the skull, protruding through the opening where the skull meets the spinal cord. It typically develops before birth and affects roughly one in every 2,000 individuals. The exact cause of the condition remains unknown.

Notably, Chiari malformation affects approximately 1 in 2,000 people, but having four siblings diagnosed is exceptionally unusual. Experts believe a possible genetic link is at play, though only about 10% of Chiari malformation cases are believed to be hereditary.

Dr. David Harter, director of pediatric neurosurgery at NYU Langone, explained to CBS News that Chiari malformation places pressure on the brain and spinal cord, leading to symptoms like limb weakness, breathing issues, scoliosis, headaches, and nerve pain. If not treated, the condition can cause chronic pain, nerve damage, and even paralysis. (NDTV)