Neurocognitive and Behavioral Issues in PKU

Neurocognitive and Behavioral Issues in PKU Susan Waisbren, PhD Associate Professor of Psychology Harvard Medical School Children s Hospital Boston Boston, Massachusetts Content developed in conjunction with Desiree A. White, PhD, Associate Professor, Department of Psychology, Washington University, St. Louis, Missouri

Faculty Disclosure It is the policy of The France Foundation to ensure balance, independence, objectivity, and scientific rigor in all its sponsored educational activities. All faculty, activity planners, and staff participating in this activity will disclose any significant financial interest or other relationship with manufacturer(s) of any commercial product(s)/device(s) and/or provider(s) of commercial services included in this educational activity. The intent of this disclosure is not to prevent a person with a relevant financial or other relationship from participating in the activity, but rather to provide participants with information on which they can base their own judgments. The France Foundation has identified and resolved any and all faculty conflicts of interest prior to the release of this activity. Susan Waisbren, PhD, has received research grants/support from and served as a consultant for BioMarin. Desiree White, PhD, has received research grants/support from, served as a consultant for, and received honoraria from BioMarin.

Educational Learning Objective Describe the impact of elevated Phe on longterm patient outcomes

KEY POINTS 1. High Phenylalanine (Phe) levels harm the brain 2. Traditional therapies do not completely protect individuals with PKU 3. Neuropsychological follow-up is important in identifying deficits associated with even well-treated PKU

KEY POINT #1 High Phenylalanine (Phe) levels harm the brain. 1. Evidence 2. Dopamine hypothesis 3. White matter hypothesis

Blood Phe and IQ Are Correlated in Individuals With PKU Observation period Critical period (0 12 years old) Lifetime (all ages) Correlation between blood Phe and IQ Lifetime IQ loss for each 100 µmol/l (1.6 mg/dl) increase in blood Phe (IQ points) r = -0.35* 1.3 3.1 r = -0.34* 1.9 4.1 * P < 0.05 Waisbren SE, et al. Mol Genet Metab. 2007;92:63-70.

Outcomes for Adults with PKU Are Worse if Discontinue Diet Outcome Discontinued Diet Continued Diet Medical Problems 2.4 ± 1.8 0.9 ± 1.4 College Degree 32% 78% Socioeconomic Class I or II* 19% 44% *Two highest socioeconomic classes in the Hollingshed classification system Koch R, et al. J Inherit Metab. 2002;25:333-346.

Figure adapted from Youdim MB, et al. Nature Rev Neurosci. 2006;7:295-309. Image from http://nobelprize.org/nobel_prizes/medicine/laureates/2000/press.html. Accessed Oct ober 2010. Prefrontal Cortex Is Sensitive to Reductions in Dopamine Blood Brain Barrier Dopamine Pathways Periphery (mostly liver) Brain PAH = phenylalanine hydroxylase BH4 = tetrahydrobiopterin TH = tyrosine hydroxylase AADC = aromatic amino acid decarboxylase

White Matter Image from: RC McKinstry Washington University Mallinckrodt Institute of Radiology Myelin insulates axons to increase speed of neural signal transmission Image from: http://kvhs.nbed.nb.ca/gallant/biology/schwann_myelin.html. Accessed October 2010.

KEY POINT #2 Traditional therapies do not completely protect individuals with PKU. 1. Adherence 2. Cognitive abilities 3. School achievement 4. Executive functioning 5. Processing speed 6. Emotional issues

% Above Recommended Range. Adherence to Diet Is Difficult ~1 in 3 children less than 10 years of age have blood Phe above recommended range Noncompliance increases in adolescence 90 80 70 79% 60 50 50% 40 30 28% 27% 20 10 0 0 4 years 5 9 years 10 14 years 15 19 years Adapted from Table 2 of Walter JH, et al. Lancet. 2002;360:55-57.

Wechsler Intelligence Scale IQ. Wechsler Intelligence Scale IQ. Children with PKU on Diet Are at Risk for Lowered IQ P < 0.001 130 P < 0.0001 120 120 Gassio et al 2005 110 Koch et al 1984 110 100 100 90 90 80 80 70 Peers PKU 70 Siblings PKU Blood Phe and IQ are correlated Waisbren et al 2007 Variability in Blood Phe may be important Anastasoaie et al 2008 Gassio R, et al. Pediatr Neurol. 2005;33:267 271. Waisbren SE, et al. Mol Genet Metab. 2007;92:63-70. Koch R, et al. J Inherit Metab Dis. 1984;7:86-90. Anastasoaie V, et al. Mol Genet Metab. 2008;95:17-20.

% Students With School Problems. Children with PKU on Diet Present More School Problems than Unaffected Peers 60 50 P < 0.03 50% Total school problems Required special tutoring Repeated classes 40 39% 30 20 10 12% 24% 19% 5% 0 PKU Students Unaffected Peers Gassio R, et al. Pediatr Neurol. 2005;33:267-271.

Executive Functioning Deficits We don t know if he s missing or just lost under all that paper! Planning Organization Working memory Initiation Inhibition of usual response Cognitive flexibility

Summary Memory Score Executive Deficits Across the Lifespan that May Worsen with Age 8 7 6 5 4 Control PKU 3 2 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Age (years) White et al 2001 Diamond A, et al. Monogr Soc Res Child Dev. 1997;62:1-208. Huijbregts SC, et al. Neuropsychology. 2003:17,369 379. Araujo GC, et al. Neuropsychology. 2009;23:130-134. Channon S, et al. Neuropsychology. 2004;4:613-620. VanZutphen KH, et al. Clin Genet. 2007;72:13-18. White DA, et al. J Int Neuropsychol Soc. 2002;8:1-11. White DA, et al. Neuropsychology. 2001;15(2):221-229.

Executive Deficits Make Diet Adherence Difficult Planning diet Remembering Phe intake for records Remembering to take formula Inhibiting impulse to eat foods not allowed on diet Maintaining medical food supplies Monitoring blood Phe and making appropriate adjustments in intake

Test Score. Time to Rapid Retrival. Speed of Processing Is Reduced in Children with PKU Control PKU 14 12 10 8 6 P < 0.01 P < 0.01 80 70 60 50 40 30 P < 0.01 4 20 2 10 0 Symbol Search Coding 0 Contingency Naming Anderson PJ, et al. Dev Neuropsychol. 2007;32(2):645-668.

% Patients Reporting Symptom. Adults with PKU Demonstrate Increase in Psychiatric Symptoms 40 37 Control PKU 35 30 31 25 20 15 10 5 0 19% Depressed Mood 16% Phobias 14 14 5% 5% Generalized Anxiety Psychiatric Symptoms Hypochondriac Worries 1% 6 Anxiety at Work *P < 0.05 compared with 18-year-old controls Adapted from Table 3 of Pietz J, et al. Pediatrics. 1997;99:345-350.

KEY POINT #3 Neuropsychological follow-up is important in identifying subtle deficits associated with even well treated PKU. 1. Case study 2. Screening by non-psychologists 3. The Genetics and Metabolism Psychology Network

Case Study: A.D. History Male with PKU, now age 11 years Newborn screening level 30 mg/dl Over-treated until 17 months Failure to thrive and mild microcephaly Poor metabolic control from ages 2 4 years, until g-tube placed for intake of formula Levels varied until age 10 years 3.6 16.9 mg/dl ADHD medication required IQ = 81 (100 is average)

Case Study Recent and Current Began treatment with sapropterin at age 10 Blood Phe steady at 5.4 mg/dl No longer needs ADHD medication Height 5 th percentile; weight 2 nd percentile IQ = 105 (Increase of 24 points)

Case Study Current 11-year-old boy in 4 th grade Continues with g-tube Eczema and bedwetting Receives occupational therapy Has attention problems and requires one-on-one aide in classroom Kind, imaginative, eager to please Enjoys socializing, video games, sports

Assessment Observations Polite, cheerful, talkative Concentrated fairly well, but hummed as worked Enjoyed relating facts about spiders Told far-fetched stories about school and home, stating these capture interest of other children Did not appear to believe stories, but rather to intentionally elaborate

WASI Score 120 Intellectual Performance Wechsler Abbreviated Scale of Intelligence (WASI) 100 80 60 Average AD 40 20 0 Vocabulary Matrix Reasoning Full Scale IQ

Executive Functioning Example List Carrot Taxi Elephant Car Airplane Lettuce Cat Potato Butterfly Spinach Boat Tiger Scooter Squash Parrot California Verbal Learning Test Trial 1: 4 words Trial 5: 9 words (Used categories) Previous Year Trial 1: 3 words Trial 5: 5 words

Processing Speed Example of a Symbol Search Task ø ƒ YES YES NO NO

WISC-IV Subtest Score Wechsler Intelligence Scale for 12 Children 10 8 Average AD 6 4 2 0 Symbol Search Coding

Academic Achievement (WIAT) Reading Recognition: 5 th grade level Reading increased 1 grade in last year Numerical Operations: 3 rd grade level Careless errors, could not borrow or carry, did not attempt adding long columns of numbers Math increased 1/2 grade in last year WIAT: Wechsler Individual Achievement Test

Visual Motor Integration Berry Visual Motor Integration Test (VMI): Standard Score = 70 (100 is average) Drew with confidence, but poor organization so details misplaced. Same score as last year.

Recommendations Continue with extra help and occupational therapy Teach compensatory strategies in arithmetic Psychological counseling Behavioral therapy for weaning from g-tube Medical evaluation for eczema and bedwetting Re-evaluation in one year

Screening Tests That Can Be Administered by Non-Psychologists PSYCHOLOGICAL REALM TEST Adaptive Functioning Adaptive Behavior Assessment System (ABAS-II) Behavior Executive Functioning Behavior Assessment System for Children (BASC-II) Behavior Rating Inventory of Executive Function (BRIEF)

Abbreviations & Sources ABAS-II: Adaptive Behavior Assessment System- Second Edition (Harrison, Oakland 2003) BRIEF: Behavior Rating Inventory of Executive Function (Gioia, Isquith, Guy, Kenworthy, 2000) BASC-II: Behavior Assessment System for Children- Second Edition (Reynolds, Kamphus, 2004) BAI: Beck Anxiety Inventory (Beck, Steer,1993) BDI-II: Beck Depression Inventory-Second Edition (Beck, Steer, Brown,1996)

Genetics and Metabolism Psychology Network