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PKU in adolescents and adults Andrew Morris Royal Manchester Childrens Hospital.

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Presentation on theme: "PKU in adolescents and adults Andrew Morris Royal Manchester Childrens Hospital."— Presentation transcript:

1 PKU in adolescents and adults Andrew Morris Royal Manchester Childrens Hospital

2 Manchester PKU patients children (n=115) adults (n=211) Number Age (yrs)

3 High phenylalanine levels are harmful to the developing brain Phenylalanine must be strictly controlled in infancy, childhood and in pregnancy Stopping the PKU diet after childhood does not have a major effect on IQ

4 Adult PKU management Prevention of Damage to children of PKU mothers Nutritional problems Late neurological problems (?)

5 PKU & Pregnancy Low risk of child having PKU (1:100) High risk of child being damaged by mothers high phenylalanine levels

6 Untreated Maternal PKU Adverse effects on infant Mental retardation (92%) Abnormally small head (73%) Low birth weight (40%) Congenital heart disease (12%) Abnormal facial appearance Lenke & Levy, 1980

7 Congenital heart disease International study Diet pre-0/23 conception(0%) Diet after 10 34/235 weeks gestation (14%)

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10 Maternal PKU: when to start strict diet International study recommended levels down by 10 weeks gestation BUT - takes time to get levels down - vomiting in early pregnancy Pre-conception If unplanned as soon as possible If very late consider termination

11 Maternal PKU: Problems Diet is difficult Cost Waiting to conceive whilst on diet –refer to reproductive medicine after 6 months Vomiting Learning difficulties in some patients Poor support from some doctors

12 Adult PKU management Prevention of Damage to children of PKU mothers Nutritional problems Late neurological problems (?)

13 Nutrition in PKU Adults On PKU diet Supplements often taken erratically Off PKU diet Diet often low in red meat & dairy foods –low in vitamin B12 iron calcium

14 strict n=25 relaxed n=30 normal n=29 Vitamin B12 levels in PKUs on & off diet B12 level in blood (ng/l) Diet : 136Pts with low B12 Normal Range

15 Adult PKU management Prevention of Damage to children of PKU mothers Nutritional problems Late neurological problems (?)

16 Adults with PKU High phenylalanine levels cause Minor symptoms in some patients –Poor concentration –Lethargy –Irritability

17 Adults with PKU High phenylalanine levels cause Minor symptoms in some patients Abnormalities on brain scans –White matter –Reversible if phenylalanine lowered

18 Normal White matter changes Probably due to increased water content

19 Adults with PKU High phenylalanine levels cause Minor symptoms in some patients Abnormalities on brain scans Neurological problems (very rare)

20 Stiffness Poor balance Epilepsy Poor short term memory Very rare Most patients had poor early control Often reversible on restarting diet Neurological problems after stopping PKU diet

21 Adults with PKU High phenylalanine levels cause Minor symptoms in some patients Abnormalities on brain scans Neurological problems (very rare) Unknown effects in very long term –No early treated patients have yet reached 50 yrs

22 Adolescents with PKU Poor dietary control may lead to disappointing exam results No good studies –families with good dietary compliance also likely to encourage studying –randomised controlled trials not possible

23 Adolescents: recommendations Dietary treatment Phenylalanine levels mcmol/l Not worth pursuing if leads to Family breakdown Serious nutritional problems

24 What are we achieving ? % phe samples outside target range Age Target range

25 Management of adults with PKU PKU clinics provide information Patients choose whether to stay on diet Everyone needs regular review to Support patients on diet Prevent nutritional problems Monitor for neurological problems Ensure strict diet during pregnancy

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27 Treatment of PKU Phenylalanine restricted diet Amino acid supplements Low protein products Vitamins & Minerals Monitoring of phenylalanine levels

28 Adult PKU: neurological abnormalities Brisk reflexes Tremor Asymptomatic Common On or off diet

29 Scan abnormalities and phenylalanine level Severity of abnormality on scan Phe

30 Phenylketonuria PhenylalanineTyrosine PA Hydroxylase BH 4 BH 2 DHPR Phenylketones

31 Published guidelines UK (1993) pre-school: µmol/l (2-6 mg/dl) school age: µmol/l (2-8 mg/dl) adolescence: µmol/l ( mg/dl) German (1999) <10 y µmol/l (0.7-4 mg/dl) y µmo/l ( mg/dl) >15 y µmol/l ( mg/dl)

32 Management of PKU adults in UK UCH is the largest centre with 270 adult patients


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