Metabolic Camp: old friends, new tech

For many kids, summer camp is a chance to eat lots of what they like. Every June, Emory’s Department of Human Genetics hosts a camp for young women who can’t eat what everyone else eats.

Metabolic Camp was designed for young women with PKU (phenylketonuria) or MSUD (maple syrup urine disease), who have to limit their intake of naturally occurring protein to stay healthy. This means: no meat, fish, poultry, dairy, or even bread. 

The camp, which takes place at two fraternity houses on Eagle Row, focuses on nutrition, genetics and reproductive health classes, paired with cooking workshops, wellness and other fun activities. It’s an environment where researchers can test new technologies that could make campers’ lives easier -- with rigorous IRB-approved research. At the same time, campers can reconnect with old friends and meet new ones who understand their daily lives.

According to a recently published survey, many people with PKU were made fun of and experienced bullying as children because of their specialized diet requirements. “I got bullied in school, but it made me a stronger person,” said Stephanie Chaput, who attended Emory’s metabolic camp as a teenager and is volunteering this summer to mentor current campers.

“Don’t call PKU a disease,” she added, because other children sometimes get the idea that it is infectious or contagious.

An assistant counselor with PKU, Ria Glushkova, said: “When I was a kid, I did not understand why I was the odd one out. I don’t want other kids to feel as helpless as I did.”

Understanding PKU and MSUD

PKU is an inherited deficiency in an enzyme that processes the amino acid phenylalanine. If someone with PKU consumes a standard diet, then over time, phenylalanine (or Phe)  accumulates to high levels in their body, leading to neurological damage, intellectual disability and sometimes seizures. MSUD -- which is rarer than PKU and gets its name from a maple syrup smell in the urine of untreated indivduals – arises from an inherited deficiency in processing another set of amino acids: leucine, isoleucine and valine.

PKU and MSUD are usually diagnosed as a result of newborn screening: a heel-prick blood test performed just after birth for all infants in the United States. If the condition is identified in time, families can work with a metabolic dietitian to intervene and adjust the  infant’s diet to avoid future complications. To get enough ”good” amino acids, the building blocks of protein, people with these conditions usually need to drink specialized nutrition formulas that lack the amino acids their bodies can’t handle.

While both boys and girls can have PKU (or MSUD), Emory’s Metabolic Camp is oriented around young women, because of the need to prevent maternal PKU syndrome. During pregnancy, high phenlyalanine levels in the mother can harm a developing fetus, even if the fetus does not have PKU, says Rani SinghPhD, RDN, professor of human genetics and pediatrics, who has focused her research and patient care on inborn errors of metabolism and nutritional management for over 30 years. She is co-director of the Bionutrition Research Unit of the Georgia Clinical and Translational Science Alliance and director of Medical Nutrition Therapy for Prevention program (MNT4P).

“I felt it was critical to catch these women early on and to teach them about prevention,” she says. “It is possible to have a healthy baby if the mom controls her Phe levels.”

Times they are a-changing

Dr. Singh started Emory’s Metabolic Camp in 1995, before any prescription medications were available for PKU. Since then, two medications for PKU have been tested in clinical trials and approved by the Food and Drug Administration. No medications have been developed for MSUD.

The most recent approval in 2018 was Palynziq, a replacement for the enzyme that is deficient in people with PKU. If injected regularly, Palynziq can allow someone with PKU to consume an unrestricted diet.

Stephanie Chaput was diagnosed with PKU through newborn screening and grew up drinking nutrition formula, although she is now taking Palynziq. She credits the medication with enabling her to have a healthy baby.

 “I still have the hardest time with regular food – but I love French fries,” she said.

While life-changing for some people, Palynziq was approved for adults only, and it’s not currently available for kids or teens. Even with Palynziq, close monitoring of Phe blood levels is required to make sure patients don’t experience long-term neurological problems. Some adults with PKU don’t take Palynziq, because of side effects such as anaphylaxis, or lack of insurance coverage; even with insurance, the co-pays can cost hundreds of dollars per month.

Right now, two drugs are being tested in clinical trials that could change daily life for people with PKU. One of them blocks the kidneys from reabsorbing phenylalanine, allowing Phe to be excreted in the urine; the preliminary results are positive.

“There are a lot more opportunities coming up now for PKU than for many other metabolic disorders,” said Stephanie Hacker, a metabolic dietitian from the University of Miami, at a discussion group covering current clinical trials.

She told the group of campers: “These companies need your participation in clinical trials for their products to succeed.”

Campers asked whether newer medications will be available for younger ages (teenagers) and if their side effect profiles were similar to existing drugs.

One technological advance that potentially could change the lives of people with PKU is not a drug. Instead, it’s a device that can measure someone’s blood Phe levels at home. It would be analogous to someone with diabetes being able to monitor their glucose level using test strips.

Currently, people with PKU send blood spot samples to a laboratory, and receiving results can take weeks. One camper from Alaska said she needed to send her samples to Idaho for processing.

Singh’s research team is collaborating with Egoo, a company based in Denmark, for a clinical study testing a point-of-care device that measures Phe levels quickly. At camp, Singh’s team got a chance to try the device out.  Two drops of blood from a patient with PKU  are squeezed into a cartridge, which is inserted into the Egoo Analyzer – about the size of a large coffee mug. The analyzer provides results in about 30 minutes. The Egoo device is being tested at Emory in a research protocol to compare its accuracy to established methods of measuring Phe. It is not yet available commercially.

“That thing was awesome,” said Georgette Aad, another adult camp liaison with PKU. “It would be fantastic! You could quickly see how your body reacts to your diet.”

Although Singh cautions that PKU community members have tested similar devices before, she says: “I think that’s the most exciting development this year. We have to get this process away from the white coats, and make it more convenient and approachable for individuals living with PKU.”