The Mothers Who Built Newborn Screening

Newborn screening exists because families forced it into existence. The test, the diet, the legislation, and the infrastructure that now screens four million newborns a year in the United States all trace back to mothers who refused to accept that nothing could be done, a microbiologist who took their side against organized medicine, and a political fight the families won.

PKU is the founding condition of newborn screening. Every heel prick in every hospital in every state descends from it.

A Mother in Oslo, 1934

Borgny Egeland had two children, ages four and six, with progressive intellectual disability. Both had an unusual smell. She brought them to Asbjørn Følling, a physician and biochemist at Oslo University Hospital, looking for an explanation.

Følling added ferric chloride to the children's urine. It turned dark green. That reaction was wrong for every known metabolite. It took Følling six more weeks and 20 liters of the children's urine to identify the substance: phenylpyruvic acid, a breakdown product of the amino acid phenylalanine. The children's bodies could not process phenylalanine. It accumulated, and it damaged their brains.

Følling tested urine from more than 400 people in institutions across the Oslo area. He found eight more with the same acid. He published the finding in 1934 as a new inborn error of metabolism. The condition was eventually named phenylketonuria, PKU.

Følling had identified the error. The question of what to do about it would take another 17 years, and it would be answered by another mother.

A Mother in Birmingham, 1951

Sheila Jones was two years old, living in Birmingham, England, with PKU. Her mother Mary brought her to Birmingham Children's Hospital, where three researchers were studying the condition: Horst Bickel, a German-born pediatrician; John Gerrard, a physician; and Evelyn Hickmans, the hospital's chief biochemist.

Bickel later described Mary Jones in his notes. She waited outside the laboratory door every morning. She made clear she wanted treatment for her child, not investigations. She did not accept that there was no therapy. Her persistence, Bickel wrote, gave him no chance to rest on the strength of a fine diagnosis.

Bickel's team attempted something that had never been done. They took casein, the protein in milk, broke it into its amino acid components through acid hydrolysis, and passed the result through activated charcoal to strip out phenylalanine. What remained was a protein source with nearly all the phenylalanine removed. They mixed it into a formula and fed it to Sheila.

Her blood phenylalanine levels dropped. Her behavior improved. The intellectual deterioration slowed. The diet worked.

Bickel, Gerrard, and Hickmans published the results in 1953. Within a year, Allen and Hanburys in England began manufacturing the formula commercially under the name Cymogran. In 1958, Mead Johnson in the United States produced Lofenalac, the first American commercial PKU formula.

The diet existed. A mother's refusal to accept the diagnosis as a dead end had produced it. The problem that remained was detection. The diet could prevent brain damage only if PKU was identified in the first weeks of life, before phenylalanine accumulated. Every week of delay was permanent, irreversible harm. There was no population-level test.

A Microbiologist in Buffalo, 1958

Robert Guthrie was a microbiologist and physician at the University of Buffalo. His second son, John, was born with intellectual disability in 1947. In 1958, Guthrie's niece, a 15-month-old girl, was diagnosed with PKU. The diagnosis came too late. By 15 months the damage was done. If her PKU had been found at birth, the diet could have prevented it.

Guthrie already knew the biochemistry. He had the microbiology skills. The combination of personal grief and technical capability produced one of the most consequential diagnostic tools in medical history.

The test was elegant in its simplicity. Guthrie knew that the amino acid beta-2-thienylalanine inhibits the growth of the bacterium Bacillus subtilis. He also knew that phenylalanine reverses that inhibition. He coated an agar plate with the inhibitor, placed a disk of dried blood from a newborn's heel prick onto the plate, and waited. If the blood contained excess phenylalanine, the bacteria grew in a visible ring around the disk. If not, nothing happened. The test cost pennies. It required a single drop of blood on filter paper. It could be mailed from any hospital to a central lab.

Robert Warner, a physician at the Children's Rehabilitation Center in Buffalo, had first asked Guthrie to develop a simpler PKU test in 1957. By 1960, the bacterial inhibition assay was ready for large-scale trial.

Parents Against the AMA

What happened next is a political story, and it is the part of PKU history that matters most for understanding why families, and only families, drive lasting change in rare disease.

Guthrie tried to publish through normal channels. Medical journals were slow to accept his work. He was a microbiologist, not a metabolic disease specialist, and the establishment was skeptical. So he went around it.

The National Association for Retarded Children (NARC, now The Arc) was an organization of parents. Its president and executive director urged Guthrie to publish his results quickly, as a letter to the editor, timed to coincide with NARC's 1961 awareness campaign. The campaign poster featured two young sisters with PKU. Guthrie's test kits went out with NARC labels reading: "Retarded children can be helped."

In late 1961, the U.S. Children's Bureau funded a field trial. Guthrie's team tested 404,568 infants across 29 states over two years. They found 37 cases of PKU. The test worked at population scale.

In 1963, Massachusetts became the first state to mandate PKU screening for every newborn. The legislation passed because parents and NARC pushed it through, directly lobbying state legislators.

The American Medical Association pushed back. In 1964, the AMA House of Delegates voted to oppose legislation requiring compulsory testing for PKU. State medical societies, with the single exception of Massachusetts, followed the AMA position. The objection was framed in scientific and ethical language: the test was too new, the long-term benefits of the diet were unproven, mandatory testing intruded on the physician's clinical judgment.

Samuel Bessman, a biochemist, argued publicly that PKU might not require treatment at all, that the apparent benefits of the diet could be placebo effects. Howard Cooper, a political scientist, testified at legislative hearings that screening would divert attention from the broader needs of people with intellectual disability.

Guthrie and the families did not wait for the medical establishment to come around. They took the case directly to parents, legislators, and the press. NARC chapters organized in every state. Parents testified at hearings. Legislators who had never heard of phenylalanine learned one fact that was sufficient: a $2 test at birth could prevent a lifetime of intellectual disability. The cost arithmetic was unanswerable.

By 1965, 32 states had enacted PKU screening laws. By 1967, 37 states. The AMA's opposition was overrun by parents who had no interest in waiting for a consensus that the medical profession was in no hurry to reach.

What the Families Built

Every piece of the PKU infrastructure was driven by families.

The discovery began with Borgny Egeland bringing her children to Følling in 1934. The diet was born from Mary Jones refusing to leave Bickel's laboratory in 1951. The test was propelled by Guthrie's grief over his son and his niece. The legislation was carried by parents through NARC, state by state, against explicit opposition from the AMA and nearly every state medical society in the country.

The institutions arrived later. They standardized. They scaled. They took credit. The federal Recommended Uniform Screening Panel now includes more than 35 core conditions. Tandem mass spectrometry screens for dozens of metabolic disorders from a single blood spot. The infrastructure is real and it saves lives every day.

The families built the foundation. The mothers built the foundation.

Pearl S. Buck, whose daughter Carol had PKU (confirmed by physicians in the 1960s, decades after the damage was done), published a memoir in 1950 called "The Child Who Never Grew." It was the first prominent public account of raising a child with intellectual disability in America. Buck wrote it because no one else would say it out loud. The silence around intellectual disability in the 1950s was total, and a Nobel laureate broke it because she was also a mother.

The pattern holds across rare disease. The people who live with a condition every day are the only ones who never leave. Researchers retire. Grant funding ends. Companies exit markets. Government committees get dissolved. The family is still there in the morning.

PKU proved this in 1963, when the families overrode the AMA, and it remains true in 2026. The rare disease infrastructure that lasts is the infrastructure the families build, because they are the only stakeholder whose commitment does not depend on a funding cycle, a profit margin, or an election.