Two unrelated children were taken to the doctor after their appetites became uncontrollable.
The children, a 14-year-old and a 2-year-old, did not know one another and did not share any behavioral characteristics that might lead to the shared condition.
They were suffering from “intense hyperphagia,” or excessive and uncontrollable eating, according to a case report published on June 15 in The New England Journal of Medicine.
Their appetite caused them to gain weight at alarming speeds, classifying them both as obese, according to the case report.
In the United States, 14.7 million children between the ages of 2 and 19 were affected by obesity between 2017 and 2020, according to data from the Centers for Disease Control and Prevention.
Obesity in childhood can lead to serious chronic conditions, the CDC says, including high blood pressure, high cholesterol, type 2 diabetes, breathing issues — like asthma and sleep apnea — and strain on joints.
For these two children, their early obesity was reaching a critical point that could set them up for a lifetime of health struggles.
Along with an insatiable appetite and high weight, researchers noticed that they had alarmingly high levels of leptin.
Leptin is a hormone that helps regulate fat intake in the body, Clifford Rosen, M.D., said in an editorial that accompanied the case report.
Leptin works by binding with a receptor in the brain that causes the body to “increase energy expenditure” and decrease “food intake,” Rosen wrote.
In other words, leptin allows the body to know when it is feeling hungry and when it is full, adjusting how much energy your body spends based on how much you’ve eaten.
“Leptin was once hailed as a treatment for most cases of childhood obesity but quickly lost favor when resistance to leptin was noted,” Rosen wrote.
The 14-year-old was described as the child of second-degree cousins, and the 2-year-old was described as the child of first-degree cousins, leading the doctors to look for a genetic explanation for their elevated leptin.
The researchers took cells from the children’s livers and isolated three different types of cells that appeared to be overexpressing LEPRb, the gene that creates leptin.
They found that the leptin proteins being created were not binding to the leptin receptors in the brain, meaning the children’s bodies weren’t being told to stop eating, making them feel, instead, constantly hungry.
But, the children each had a different variant causing the binding to stop.
A leptin receptor deficiency is incredibly rare, with only 500 to 2,000 people experiencing the condition in the United States, according to a 2021 report from Rhythm Pharmaceuticals.
Both children were started on a treatment of metreleptin, a leptin alternative that is created artificially, but they had no effect.
In an experimental treatment, the researchers increased the dose by more than five times, and suddenly they started to see results.
The 14-year-old lost 160 pounds, or 40% of his bodyweight, in 264 days, the report said.
The 2-year-old lost 21 pounds, or 36.5% of her bodyweight, in 238 days, according to the report.
“The fact that we were then presented with two patients within a short period of time with two different variants that had these characteristics was a surprise,” study author Martin Wabitsch told MedPage Today. “This was the basis for a successful treatment. This is exciting and a novelty for human medicine.”
The researchers believe the success of the increased dosage of leptin alternative may be a breakthrough in addressing childhood obesity.
Wabitsch told MedPage Today clinicians should “first think of and look for a genetic cause in children with extreme obesity,” in addressing a child’s health.
---------
