"Dr. Koch is really into the stuff that helps our generation," says Christian Lutz, 28, a Granada Hills man who was found to have PKU in the early years of the screening program. "He's a lifesaver. What can you say beyond that?"
Koch's mission these days is to alert hundreds of adults with PKU that they--and the children of female patients--may be at risk for serious health problems if they have gone off the special no-phenylalanine diet.
Many PKU adults who have abandoned the diet may not know they are still at risk.
In the 1960s and '70s, PKU children were typically allowed to go off the diet (which is so restricted it makes Weight Watchers frozen meals taste like the best French gourmet food) between the ages of 6 and 10, Koch says. Many children were discharged from their doctors' care to go off and eat hamburgers and French fries and live normal lives.
But in the late '70s and early '80s, health officials began to notice that the first generation of PKU women treated with the diet were having babies who were mentally retarded. These children did not have PKU; the disorder is the result of a defective gene that must be carried by both parents. Instead, these babies often had microcephaly, which features a small head and mental retardation. Some infants also suffered from intrauterine growth retardation, in which the baby fails to grow properly, and congenital heart defects.
It was clear that in PKU mothers who were on a regular diet, high blood levels of phenylalanine were causing damage to the fetus. The problem probably should have been foreseen, Koch says.
"Logically, we should have thought of it. But I think we were so enthused about these first PKU patients even being normal. That in itself was a shock," he says.
The ability to so dramatically alter an individual's fate had a powerful impact on the first group of doctors to apply the special PKU diet to newborns. Koch had seen mentally retarded PKU patients during medical school: "It left quite an impression on me."
He even remembers the first baby he treated. It was 1965, the year before the state implemented newborn screening, and Childrens Hospital was already testing the process in a pilot program. Koch was handed a baby girl.
"She has done very well," he says, noting that her IQ is normal. "But she went off the diet and I'm trying to get her back on. I'm worried for her future."
He also worries incessantly about the babies of PKU mothers. Alarmed by the irony of a new generation of mentally retarded babies born to mothers who themselves had barely escaped mental retardation, Koch applied for grant money in the early '80s to study the problem. He wanted to test the theory that re-implementing the restricted diet before pregnancy or early in the pregnancy could protect the babies born to PKU mothers.
His request was refused--twice--before he received funding in 1984. Since then, Childrens Hospital has become the hub for 178 clinics nationwide that collect data on PKU patients. So far, Koch's team at Childrens has been able to supply evidence that the sooner the pregnant woman begins the diet, the better the chances her baby will be born healthy.
Part of the study's success was due to Koch's coordination of the participating clinics. "It's a testimony to his ability to bring together people from diverse disciplines and agree on a common goal," says Eva Friedman, associate director of the Maternal PKU Collaborative Study. "He does not take offense easily or personalize criticism, but he enhances collaboration."
As the study yielded evidence in the late '80s, a movement began to locate the first generation of female PKU patients and warn them about the risk to their babies. Even the American Public Health Assn. and the American Pediatrics Assn. issued statements a few years ago urging obstetricians to look for women at risk.
But the quest to find the oldest of the diet-treated PKU patients and attract them back into PKU clinics has not been easy.
Nowadays, the parents of baby girls born with PKU are taught about the importance of keeping their daughter on the diet and the implications if she becomes pregnant, says Dr. George Cunningham, chief of the genetic diseases section for the state's Department of Health Services. His office dispatches newsletters to PKU families and even sponsors a PKU camp each summer for adolescent girls.
But women with PKU who move into California from elsewhere often escape the notice of the state health department. Others move and fail to leave forwarding addresses. Some mentally retarded adults with PKU, who were born before the screening program was implemented, are also giving birth without understanding the risk to their babies, Koch says.