What Caused This Man's Scalloped Pupil?
By Rachael Rettner, Senior Writer
July 31, 2018 06:37am ET
A man's pupil had an unusual "scalloped" shape with irregular edges, the result of a rare genetic condition.
The 46-year-old man's symptoms were concerning but not particularly strange: He was losing weight, experiencing episodes of fainting and having trouble walking. But when doctors examined his eyes, they saw something odd: One of his pupils was smaller than the other, and it had an unusual, scalloped shape with irregular edges. The strange shape of the man's pupil turned out to be due to a rare genetic condition.
Nearly two decades earlier, when the man was 29, he had a liver transplant to treat a genetic condition called familial amyloid polyneuropathy (FAP).
This condition causes abnormal deposits of a substance called amyloid to build up in the body's tissues and organs. These deposits most frequently occur in the peripheral nervous system, or the nerves that connect the brain and spinal cord to muscles and cells that detect sensations throughout the body. As a result, the deposits often lead to a loss of sensation in the extremities, but the condition can also affect other systems and organs, including the heart, kidneys, eyes and gastrointestinal tract.
In this man's case, the deposits consisted of a protein called transthyretin, which is produced mainly by the liver. Because of this, a liver transplant is recommended as the "gold standard" of care for patients. A liver transplant can slow or halt the progression of neurological symptoms. But this protein is also produced in other parts of the body, including the eye, which means that even with a liver transplant, patients may still experience symptoms, including eye problems.
In patients with this type of FAP, the odd shape of the pupil results from two factors: amyloid deposits in the lens of the eye and abnormalities in the autonomic nervous system (the system that controls involuntary body functions), said Dr. Mark Fromer. Both of these problems result from the underlying genetic condition.
Dr. Fromer added that this condition is "extremely rare" and that the last time he saw a case like this was around 35 years ago, during his ophthalmology training.
Other eye problems that can result from FAP include severely dry eyes and secondary glaucoma that results from an increase in eye pressure.
There's no cure for eye problems tied to FAP, although doctors can treat symptoms such as dry eye and secondary glaucoma, Dr. Fromer told Live Science.
The pupil abnormalities would not be treated, he said.
In the man's case, doctors found that FAP had also led to a heart condition, which was causing him to faint. His heart condition was treated with a pacemaker, the report said.
The man's weight loss and walking problems turned out to be due to psychiatric factors unrelated to his genetic condition, including depression and alcohol use disorder. These symptoms went away after the man received psychiatric treatment and cut back on his alcohol consumption, the report said. Three years later, at age 49, the patient remained in stable condition.
Original article on Live Science.