Managing the diet - TYR I

Tabel 4: Nutricia Metabolic formula characteristics Example
Product	TYR Anamix
Form	Powder
Availability	400g/can
USE: Scoop or measurements
Recommended age	0-12 months or as a supplementary feed up to 3 years
Added vit/min	Yes
Protein equivalent
Carbohydrate
Fat
DHA
Fiber
Energy/kcal

Diet calculations of a newly diagnosed infant^1,2,3,4
Diagnosis	Tyrosinemia
TYR > 900 μmol/l	90 – 100% TYR/Phe free infant formula; 0 – 10% breast milk or infant formula The TYR/PHE source (breast milk of infant formula) is temporarily stopped and replaced by a TYR/PHE free infant formula of 150 ml/kg/day, which will cause a rapid fall in TYR/PHE levels. Once PHE concentrations are below 1000 μmol/l, standard infant formula or breast milk is reintroduced
TYR 500 – 900 μmol/l	75 – 90% TYR/PHE Phe free infant formula; 25 – 10% breastmilk or infant formula The breastmilk or standard infant formula is given by appr 50 mg/kg/day
TYR < 500 μmol/l	25 – 50% TYR/Phe free infant formula; 50 – 75 % breastmilk or infant formula TYR/PHE concentrations should be monitored weekly to ensure concentrations below 400 µmol/l before dietary management is started.
	Depending on plasma levels and clinical presentation at initiation, the main aim is to correct tyrosine levels within 200-400 µmol/l and maintain blood phenylalanine in the normal range as soon as possible.
Protein recommendation	Age adequate and based on bodyweight
Energy provision	Age adequate and based on bodyweight
Volume	Age adequate and based on bodyweight 6-8 feeds in 24 hours/on demand
PHE free infant formula	Standard solution: 15 grams (or 3 scoops) TYR/PHE free infant formula (TYR Anamix Infant or TYR 1-mix) + 90 mls water provides 100 ml TYR/PHE free formula
Breast feeding	Mostly 6-8 feeds are advised daily.Once blood TYR/PHE levels are stabilized within target range, the TYR/PHE free infant formula is increased by 10 ml per feed and the amount of breast feed decreases accordingly. Techniques for breastfeeding Fixed frequency of breast feeding and TYR/PHE free formula alternating TYR/PHE free formula prior to each breast feeding Measured expressed breast milk The volume will vary according TYR/PHE levels, age of diagnosis and frequency of breast feeds.
Standard infant formula	Preparation of the standard infant formula as indicated. Mostly 6-7 feeds are advised daily, the total daily amount is divided by the amount of feeds. Techniques for bottle feeding Start with the standard infant formula feed to ensure the full amount of TYR/PHE free infant formula is provided
Frequency of monitoring	Plasma TYR/PHE levels daily at initiation of the diet Reducing to 2-3 times a week Weighing: daily
Increasing TYR intake	Increase amount of standard formula Or increase frequency of feeding or volume of breast milk
Transition to solid products/weaning	In line with recommendations on food introduction for healthy population Ensure total natural protein intake will stay in line with tolerance during introduction of TYR/PHE containing solid foods Start the introduction on low protein foods gradually in line with local recommendations, like vegetables and fruits Provide the low protein foods after the breast milk or formula feeds Manage energy intake, low protein foods contain often lower energy density than breast or bottle feeds Once 8 – 12 tablespoons are consumed at one time, this can be given instead of the equivalent of the standard infant formula or breast feed Gradually introduce more texture and lumpier foods, starting at 6-8 months Finger foods can be introduced from 7 months onwards From 9 months the low protein pasta, low protein bread and potato (products) can be introduced

References

Dixon MD, MacDonald A, White F, Stafford J. In: Clinical Paediatric Dietetics. 4^th ed: West Sussex: John Wiley & Sons Limited, 2014:381-525.
MacDonald A, Evans S, Cochrane B et al. Weaning infants with phenylketonuria: a review. J Hum Nutr Diet, 2012, 25 3−10.
MacDonald A, Rylance G, Asplin D et al. Abnormal feeding behaviours in phenylketonuria. J Hum Nut Diet, 1997, 10 163−70.
Van Spronsen Fj, van Rijn G. In: Dieet bij metabole ziekten. 1^st: WKZ/UMCU Utrecht