Managing the diet - GA I

Diet calculations of a newly diagnosed infant¹
Diagnosis	GA1
Dietary management in newborn GA1 infants depends on New born screening outcome, diagnostic workups and clinical presentation	The main aim is to reduce lysine levels, being precursor amino acids for the neurotoxic GA and 3-OH-GAOn positive newborn screening result, management starts immediately: reduction of lysine intake to 100mg/kg bodyweight/day
Protein recommendation	age adequate and depending on bodyweight
Energy provision	age adequate, depending on bodyweight
Volume	age adequate, depending on bodyweight 6-8 feeds in 24 hours/on demand
lysine free, low tryptophan infant formula	Standard solution: 15 grams (or 3 scoops) lysine free, low tryptophan infant formula (GA1 Anamix Infant or GA1-mix) + 90 ml water provides 100 ml lysine free, low tryptophan formula
Breast feeding	Mostly 6-8 feeds are advised daily. Techniques for breastfeeding Fixed frequency of breast feeding and lysine free, low tryptophan formula alternating lysine free, low tryptophan formula prior to each breast feeding Measured expressed breast milk breastmilk provides around 68mg lysine/g of protein or 89mg lysine/100ml
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 lysine is provided Mixing the standard infant formula with the lysine free, low tryptophan infant formula requires the infant need to finish the full amount and does not get used to the taste of the amino acids, which can be a problem once low protein foods are introduced and the standard infant formula amount is lowered. But it assures a balanced provision of essential amino acids
Frequency of monitoring	Biochemical monitoring is difficult, since no reliable markers are available Weighing: daily
Increasing lycine 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 lysine level intake will stay in line with tolerance during introduction of natural protein 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 M, MacDonald A, White F, Stafford J. Disorders of Amino Acid Metabolism, Organic Acidaemias and Urea Cycle Disorders. In: Clinical Paediatric Dietetics. 4^th ed: Shaw V. West Sussex: John Wiley & Sons Limited, 2014:381-525: 19914636