Phe Tyr PAH BH 4 BH 2 GTP BH 4 -dependent HPA (atypical/malignant PKU) Usually mild PKU/HPA Early CNS symptoms Fe O 2 PAH deficiency Classic PKU Mild PKU Mild HPA (non PKU HPA) Phe level (μmol/l)>600 (1200) ( ) ( ) Phe tolerance (mg/day)< >800 BH 4 responseBH 4 -responsive PKU/HPA Phenylketons FeCl 3 DOPA→DA→NA→A →→→ melanin Norm <120 μmol/l Hyperphenylalaninaemias (HPA) Patomechanism, types
ExpectedSzeged Overall1: (20 case/year) 16 PAH deficiency 99% Classic PKU1:9000 (10 case/year) 10 HPA1:9000 (10 case/year) 5 BH 4 deficiency (atypical PKU) 1% 1: (1 case/year) 1 Incidence of hyperphenilalaninamias
MS/MS (aminoacid & acylcarnitine) Sampling on 3 rd day of life Primary parameter: blood Phe >102 μmol/l (norm < 120) Secondary parameter: Phe/Tyr > 1.5 Clinical circumstances! Transient hyperphenylalaninaemia prematurity (Orn, C3 ↑) parenteral nutrition (Val, Leu, Thr ↑ hepatic disease (sepsis, galactosaemia,…) drugs 0. day, screening
Positive result „normal” newborn Blood Phe μmol/l Blood Phe >360 μmol/l Clinical examination week 1-3 Repeat screening Phe ↑ Phe norm Further work-up for suspected HPA newborns
Call in the patient – no diet! Detalied clinical history, family anamnesis Physical examination Usually few or no symptoms Mild Phe elevation + feeding difficulty, hypotonia, myoclonus, seizure, salivation → atypical PKU? Laboratory studies Blood Phe, Phe/Tyr (MS/MS) urine FeCl 3, GC-MS BH4 test DNA extraction for mutation analysis EEG Clinical work-up for the suspected PKU newborns Aim: definitve diagnosis, HPA typing, starting treatment
BH4 test NEGATIVE BH4 non-responsive Classic PKU / Mild HPA BH4-responsive PKU BH4-dependent (atypical) PKU Hyperhenylalaninemia differential diagnoses POSITIVE BH4 responsive
BH4 20 mg/kg normal dietdiet blood Phe, Phe/Tyr (MS/MS) BH4 loading Phe > 360 μM POSITIVE (Phe ↓ >30%) → BH4-responsive/atypical PKU? measure pterins, DHPR
normal dietdiet POSITIVE (Phe ↓ >30%) → BH4-responsive/atypical PKU? measure pterins, DHPR Combined Phe + BH4 loading Phe < 360 μM Phe 100 mg/kg Phe 100 mg/kg BH 4 20 mg/kg blood Phe, Phe/Tyr (MS/MS)
Day 1: hours Blood Phe (umol/l) Phe (100 mg/kg) Interpreting the BH4 test result - Case Phe (100 mg/kg) BH4 (20 mg/kg) Day 2: BH4-dependent
Day 1: hours Blood Phe (umol/l) Phe (100 mg/kg) Interpreting the BH4 test result - Case BH4 (20 mg/kg) Day 2: BH4-responsive
Send DNA sample for mutation analysis to Semmelweis University, 2 nd Dept. Pediatrics Screen for 6 most frequent PAH mutation (R408W, R158Q, R261Q, R252W, IVS 10nt546, IVS12 splice-site) Whole gene sequencing Molecular genetical diagnoses
Classic PKU treament, advices Treat immediately after diagnosis Gold standard: Phe-free medical food (enriched with vitamins, trace elements, additional energy) Breastfeeding is encouraged, ⅓ of daily protein intake Diet overshoot: Phe-deficiency: lethargy, feeding problem, diarrhea, anaemia, anorexia In PKU: target Phe-level: μmol/l In HPA ( μmol/l): no treament is necessary (except pregnancy)
BH4-deficiency treament, advices BH mg/kg/day Neurotransmitter precursors: L-DOPA (Madopar 1-3, 4-7, 8-12 mg/kg/day) 5-hidroxi triptophan (Tript-OH 6-9 mg/kg/day) MAO-B blocker selegiline (0.25 mg/kg/day) Low-Phe diet if necessary
Follow-up Blood sample via mail regularly Control check-ups: 0-3 years:every 3 months 3-6 years: every 6 months > 6 years:yearly Physical examination, laboratory studies
Patient education