Several rare and serious bone conditions only become evident as affected children become toddlers. As they stand and make attempts to walk, they may show unexpected difficulty, unusual gaits, or even experience broken bones. Brittle bone disease, X-linked hypophosphatemia (XLH), hypophosphatasia, and other bone disorders in which the homeostasis of calcium and phosphate is abnormal can be acquired or genetic conditions. They are uncommon, sometimes not readily diagnosed, and their effects can be severe as bones fail to grow and strengthen.
Diagnosing these conditions requires the skill and practiced eye of a particular kind of specialist, often in a subspecialty of nephrology or endocrinology, who is able to notice the nuances of a wide range of symptoms and to definitively test for these disorders of metabolism affecting bone growth and maintenance and other body processes. The Department of Pediatrics is fortunate to have a physician with those special skills in Neil Paloian, MD, associate professor in the Division of Nephrology, and director of the multidisciplinary Pediatric Bone and Mineral Metabolism Clinic at American Family Children’s Hospital.
Paloian is also the director of the Pediatric Kidney Stone Clinic, which manages kidney stones in children, another uncommon mineralization disorder. This clinic is a collaboration among nephrologists, urologists, and nutritionists.
For his research project during his pediatric nephrology fellowship in Seattle, Paloian worked with a basic science laboratory that was investigating disorders of calcification in mice. “This is important from a nephrology standpoint,” Paloian explained, “because the kidney is one of the primary organs that balances minerals in the body.” The kidneys regulate the serum levels of calcium and phosphate by mediating transport and losses through urine. In a few years with the laboratory, Paloian learned an enormous amount about how the body forms minerals throughout the body, both appropriately and pathologically.
“It really sparked an interest in me about the field at large,” he said. “When I came here, there was really nobody doing it on the clinical side. There was a need that needed to be filled. With my background and training from my days in the laboratory, I was able to step into it.”
In addition to Paloian, the clinical staff of the Pediatric Bone and Mineral Metabolism Clinic includes Robert Steiner, MD, professor in the Division of Genetics and Metabolism; Blaise Nemeth, MD, MS, professor, and Lindsey Boyke, MD, assistant professor, both in the Department of Orthopedics and Rehabilitation. Courtney Schultz, RN, is the nurse director for the bone metabolism clinic. “She is the point person for the clinic,” Paloian noted.
Paloain and his multidisciplinary team became famous for a short time in 2021, when The New York Times Magazine, in its “Diagnosis” feature, published a story about a local toddler who showed an odd, slow gait. Luckily, a neighbor knew to bring it to a specialist’s attention (“This is a problem for Neil.”). The 17-month-old girl was found to have X-linked hypophosphatemia and was quickly provided with treatment that would allow her bones to strengthen and grow correctly.
The program treats “a couple hundred patients per year,” Paloian said. Most of the patients the clinic sees begin to come in when they reach the toddler stage, as parents don’t notice anomalies in bone growth until their children begin to walk. “We also see kids up till age 21, and there’s actually a couple of kids that we’ll follow longer until they’re in college,” he said, “waiting for a good time to transition them to adult care.” There were a few infants in the program as well, with such severe disease it was apparent at birth, but that is not typical. The program also addresses the bone deteriorating conditions that can occur due to cancer, medications, immobility, and other diseases.
Because the clinic is unusual, it draws patients from a large regional area, including all of the state, northern Illinois, northeastern Iowa, Minnesota, and Michigan’s Upper Peninsula. The clinic is open every other week; all of the providers are available together for those clinic days, with patients coming in for appointments.
“Although we’ve made a name for ourselves within the UW Health community, there are many physicians outside of Dane County and beyond who don’t know we are here,” Paloain noted. “Many don’t know that we can treat these unusual conditions. Every kid who comes to see us has been seen by a pediatrician or family doctor who has a suspicion that there’s something wrong, who has to identify that there’s something abnormal. They have to find the route to us.”
The clinic is also involved in research for data collection and in clinical trials of new drugs. Paloian noted that there are four to five clinical trials going on at any one time. He is the representative of the clinic and principal investigator for the trials; Steiner is also involved in trials. Paloian is the communicating person for the research studies.
Photo by Kate Feldt/Department of Pediatrics