Treating PKU: A Half-Century of ExperienceWhat’s Been Learned, What are some Questions

National PKU Alliance ConferenceCherry Hill, New Jersey

R. Rodney Howell, M. D.

Professor of Pediatrics, Chairman Emeritus

Member, Hussman Institute for Human Genomics

Miller School of Medicine

University of Miami

Founding Chair

HHS Secretary's Advisory Committee on Heritable Disorders

In Newborns And Children

July 27, 2012

Oslo, Norway, the Late 1920s

Harry (a young dentist) and his wife Borgny Egeland were concerned that their 3 year old daughter was very slow in speaking. While dealing with this concern, Borgny recognized she was pregnant this time with a son, later named Dag. He was early found to be very delayed

The Egelands detected a strange musty odor which they thought might be causing their children’s retardation. The father who had severe asthma was said to be unable to stay in a closed room with the children due to the odor

They sought the help of a Chemistry Professor that had taught Harry in Dental School, Dr. Asbjørn Følling (he was teaching there while in medical school). The Følling medical thesis was written on “Mechanisms of Acidosis”

Asbjørn Følling, ca 1934

The Positive Ferric Chloride Test

Borgny was asked to bring urine samples to the Følling

laboratory; routine tests were normal but when ferric chloride was added (a test for ketones which produces a red-brown color) the girl’s urine turned a dark green color which faded in a few minutes

Could the positive test be drugs or herbs? All these were eliminated, still the evanescent dark green color was present

Dr. Følling asked Mrs. Egeland to bring daily urine samples which soon totaled about 20 liters. Using laborious chemical precipitation procedures he recrystallized the compound (he could follow its presence by the positive FeCl3 test) six times and identified this compound as phenylpyruvic acid

Følling screened 434 mentally-retarded children using the urinary FeCl3 test and found 8 with the same abnormality, which he termed phenylpyruvic oligophrenia, and identified it as a defect in phenylalanine metabolism

In 1934, he published these findings, approximately 6 months after the Egelands had contacted him!

(There is an interview with Dr. Følling posted on YouTube about this discovery)

Transient Green Color seen by Følling

Bickel and Colleagues: The First Child Treated with a Synthetic Diet Low in Phenylalanine 1951

Diet made with casein hydrolysate treated with activated charcoal. tyrosine and other amino acids added and later some phenylalanine

Child 26 months old with a phenylalanine content of 67mg % prior to treatment; slow mental development

While on the diet urinary FeCl3 became negative; during next six months child appeared to improve, eyes brighter, more interest in surroundings, learned to crawl, eczema cleared; addition of more phenylalanine to diet caused regression

Authors concluded further trials needed; felt that diet not very helpful to older children and they presumed best results will occur when diet begun in infancy

(Posted on YouTube is a B & W 8mm film made by Bickel about the treatment of this first child )

PAGE 45: A NEW WAY TO DETECT A DREADFUL DISEASE-PKU

Rural China, 1920- Description by a Mother -A Famous Writer- of her Child later Found to have PKU-a Condition which had not yet been described

I don’t know any blow in all my life that was a rending. It was as if my very flesh were torn. It was beyond belief, and yet I knew I had to believe it, and shape my life around the fact

Taking this advice, the mother identified a good care-taking institution in America and Carol was placed at the Training School at Vineland. At Vineland, as an adult Carol was diagnosed as having PKU

The mother, Pearl S. Buck, won the Pulitzer Prize in 1932 and the Nobel Prize in 1938 for her books about rural China where she lived for 40 years from infancy. Her most famous book is The Good Earth was published in 1931, but was on the Oprah Book list as recently as 2002

Her book, The Child Who Never Grew published in 1950, is the world-famous author’s story of her daughter with PKU

Pearl S. Buck on her return to the United States became an advocate for the developmentally delayed, and became friends with the Kennedy Family who shared these interests. This friendship clearly help increase funding for research in phenylketonuria, and importantly to the formation of the National Institute of Child Health and Human Development.

The Collaborative Study for the Treatment for Phenylketonuria

• Large, ambitious longitudinal collaborative study instituted in 1967 to test the effects of dietary restriction of phenylalanine in the treatment of PKU

• There were two Treatment Groups: The first whose serum phenylalanine was targeted between 1.0-5.4 mg/100 ml, and the second between 5.5 and 9.9 mg/100ml

• There were two control groups: Siblings with PKU who were previously untreated, and siblings without PKU

• A sophisticated system of dietary management, monitoring, and collection, management and analysis of the data were in place

• Over 400 patients were in the original sample

The Collaborative Study for the Treatment for Phenylketonuria- Some Conclusions

• Patients with classic PKU were identified by newborn screening and began treatment soon

• All were given the restricted diet until age 6 years, when half were assigned to continue and half to discontinue dietary therapy

• By age 10 years, 35% had deviated from randomization

• The effects of diagnostic, treatment and psychosocial factors on cognitive test scores were evaluated through 12 years of age

• After controlling for parent IQ, significant correlations were noted between various measures of control of blood phenylalanine and their scores on intelligence, reading, spelling and behavior tests but not for arithmetic or language

• These findings strongly supported the importance of early initiation of dietary treatment and continuation of therapy throughout childhood

The International Maternal PKU Collaborative Study

• Designed to determine the effect of dietary control of blood phenylalanine during pregnancy in preventing damage to the fetus association with untreated maternal PKU

• Women grouped according to their mean PKU levels (µmol/L)<360, 361-600, 601-900, or >900

• Significant relationships were seen with elevations during the critical gestational weeks of 0-8, and 8-12 weeks

• Frequent, severe abnormalities in brain, fetal, and postnatal growth were seen when phenylalanine levels were above 900 µmol/L

• Women with PKU should begin a low-phenylalanine diet to achieve phe levels of <360 µmol/L prior to conception and should maintain this throughout pregnancy

Phenylketonuria: Screening and Management

NIH Consensus Development ConferenceOctober 16-18, 2000

2000 NIH Consensus Development Conference: Some Conclusions

• Genetic testing for PKU has been in place for almost 40 years and has been very successful in the prevention of several mental retardation in thousands of children and adults. Many questions, however, remain unanswered

• Metabolic control is necessary across the lifespan of individuals with PKU

• A comprehensive, multidisciplinary, integrated system is required for the delivery of care to individuals with PKU

• Greatly needed are consistency and coordination among screening, treatment, data collection and patient support programs

• There should be equal access to culturally sensitive, age appropriate treatment programs

2000 NIH Consensus Development Conference: Conclusions Continued

• Ethically sound, specific policies for storage, ownership, and use in future studies of archived samples remaining from PKU testing should be established

• Research into the pathophysiology of PKU and the relationship to genetic, neural and behavioral variation is strongly encouraged

• Uniform policies need to be established to remove from the individual and the family financial barriers to the acquisition of medical foods and modified low-protein foods, as well as to provide access to support services required to maintain metabolic control in individuals with PKU

2000 NIH Consensus Development Conference, Conclusions Continued

• To achieve optimal statistical power, as well as cross-cultural applicability, it will be beneficial to use data acquired via national and international collaboration.

• It is recommended that Phe levels below 360 µmol/L be achieved at least 3 months before conception

• Research on nondietary alternatives to treatment of PKU is strongly encouraged

• Mutation analysis and genotype determination should be accomplished on all persons with PKU for initial diagnosis, genetic and management counseling, follow-up and long-term prognosis.

Fast Forward Twelve Years LaterThe PKU Scientific Review Conference: State of the Science

and Future Research NeedsBethesda, Maryland February 22-23, 2012

• Working groups comprising topic experts, members of the public and federal representatives have been formed to review the current state of the science on difference aspects of PKU

• Long-Term Outcomes and Management across the Lifespan

• PKU and Pregnancy

• Diet Control and Management

• Pharmacologic Interventions

• Molecular Testing, New Technologies, and Epidemiologic Considerations

New Medication: Sapropterin dihydrochloride (Kuvan®)

• Synthetic form of BH4, the cofactor for the PAH enzyme

• FDA approval in December 2007 granted to BioMarin

• Indications: – BH4-responsive PKU– No age restriction – For use in combination with a Phe-restricted diet– Requires frequent monitoring of blood Phe levels and

recommended diet management with dietitian– Patient registries for those on Kuvan, including pregnant women– Approval based on 4 studies in 579 patients, 4-49 yrs old

• Mechanism: increases activity of PAH enzyme in those with residual enzyme function

Some Key Points Which Emerged at this Conference from the Working Groups

• A Reinforcement of the importance of lifelong treatment for PKU

• A Refinement of the critical elements of medical, nutritional, cognitive, emotional, behavioral, and social management of PKU throughout the lifespan, including pregnancy

•Optimal management is essential to prevent maternal PKU syndrome

• The value of double-blind, placebo controlled studies for determining responsiveness to therapies such as sapropterin

• An emphasis on the value of genotyping for categorization of severity of PKU and for prediction of responsiveness for sapropterin

• A recognition of the psychosocial, insurance and other factors that influence access to and compliance with nutrition and other therapies

• The need for more treatment options for individuals with no or minimal PAH enzyme activity

•Work that came out of this conference will inform practice guidelines and development of a research agenda

In a Word:

Newborn screening and treatment of phenylketonuria is one of the most successful public health programs of the past century. NBS expansionwas recognized by the CDC as one of the most important publichealth accomplishments of the first ten years of this century

These extremely effective programs have identified thousands of infantsand thereby prevented severe developmental delay

Treatments have been improved and refined since they were started justover 60 years ago; exciting new treatments are on the horizon

There remains significant need to further refine the available programs so thattreatments can be more effective and much easier to deal withnot only from the patient’s standpoint, but also by those charged withmonitoring and treating this infants, children and adults

The next conference about PKU and its treatment, will probably be needed much earlier than in 10 years, and will present many exciting newprograms and therapies

In Memoriam:Richard Koch, MD

1921-2011

Følling Award Recipient, 2009Richard Koch

Newborn Screening for Genetic Disease in the United States

• Routine newborn screening has been carried out in all 50 states since the 1970s; the programs have always been state sponsored public health programs, arguably one of the most successful ones

• Conditions such as phenylketonuria, with simple, reliable screening tests and proven treatment efficacy have been the targets of testing

• Over the years, congenital hypothyroidism and a handful of other diseases were added on a state by state basis

• As the programs grew and developed, there was extraordinary variation from state to state and there was little systematic evaluation of either the rationale for screening and/or the outcomes of such screening

• Over 4,300,000 infants are screened each year, making newborn screening by far the most commonly performed genetic testing in the United States

American College of Medical GeneticsContract with HRSA on Newborn Screening

• In 2001, the Maternal and Child Health Bureau, HRSA/HHS contracted with ACMG to convene an expert group to evaluate the scientific and medical information related to screening for specific conditions and to make recommendations based on this evidence.

• Widely representative group (physicians, scientists, consumers, state laboratorians, lawyers, ethicists and others) worked over a two year period to accomplish this goal, and their report was published in 2006.

• The group of over 70 developed principals by which conditions were to be evaluated, reviewed available published data, expert opinion and other materials. The two major working groups were overseen by a steering committee.

• The developed material was then reviewed by an independent newborn screening external review group

• In addition to the expert group, outside input was actively solicited

Selection Criteria of Uniform Panel• Incidence of condition• Identifiable at birth• Burden of disease• Availability of test• Test characteristics• Availability of treatment• Cost of treatment• Efficacy of treatment• Benefits of early intervention• Mortality prevention• Diagnostic confirmation• Acute management• Simplicity of therapy

Uniform Screening Panel

• 29 primary conditions

– 20 detected by MS/MS (AA, FAO, OA)

– 3 Hemoglobinopathies (S/S, S/βThal, S/C)

– 6 others (BIOT, CAH, CF, CH, GALT, HEAR)

• 25 secondary targets

– 22 detected by MS/MS (AA, FAO, OA)

– 1 Hb-pathy (many variants counted as one)

– 2 others (GAL-epimerase, GAL-kinase)

Authorizing Legislation• Title XXVI of the Children’s Health Act of 2000 enacts

three sections of the Public Health Service (PHS) Act:

– Established the Advisory Committee on Heritable

Disorders in Newborns and Children (Section 1111)

– Committee first met on June 7-8, 2004

– Although Committee charge is broad, to date

committee has focused efforts on newborn screening

http://www.hrsa.gov/heritabledisorderscommittee/

What is Happening to Drive Such Interest and Expansion in Newborn Screening?

• Newborn screening has always been technologically driven, beginning with the discovery of the ability to screen for phenylalanine elevations using the dried blood spot and the bacterial inhibition assay

• There has been an enormous discovery and understanding of new conditions, as well as the development of many therapies, some of which must begin early in infancy to save lives

• The development of MS/MS has been the single major force in our expanded ability to detect serious conditions in the newborn infant

• In addition to NBS expansion being driven by developing technology, the extraordinary efforts from advocacy groups has caused a dramatic increase in the numbers of conditions for which screening is performed

A Major Challenge to Newborn Screening

• The acrimonious public discussion about the fate of residual dried blood spots, led by a small but vocal group, could lead to restrictions which could seriously damage the newborn screening program, one of our very best public health efforts

• A key effort to calm these issues is to inform the public about the newborn screening programs, and exactly how the residual blood spots are used, and about their great value

• The SACHDNC has had a working group focusing on this subject for a long time, and has in press and article addressing the many aspects of this subject:

Committee Report: Considerations and Recommendations for National Guidance Regarding the

Retention and Use of Residual Dried Blood Spot Specimens After Newborn Screening. Genet. Med 2011, May 19 (Epub ahead of print)

The Life Cycle of Blood Spots

• Collection

• Primary testing

• Quality control, quality assurance

• Second tier testing

• Confirmatory testing

• Education

• Metabolic autopsy

• Test development

• IRB-approved research

New Important Opportunities in Newborn Screening

The recent addition of SCID to the recommended newborn screening panel was the first DNA-based test, i.e. measurement of TRECS in dried blood spots; pilot studies have gone very well

The rapid developments in the area of genomics will require extensive research and discussion of newborn screening in the context of the genomic era

The recent ACHDNC recommendation that pulse oximetry screening for critical cyanotic congenital heart disease (awaiting a recommendation from the Secretary) will add an important point of care test to the panel

Point of care screening has been discussed for such conditions as galactosemia where early answers are vital

The continued development of the newborn screening transitional research network will provide an excellent opportunity to better understand these rare diseases and their treatment(s)