Monitoring - HCU

To maintain good metabolic control and ensure optimal growth, frequent adjustments of the diet are necessary.

The following measures are used to control total plasma homocysteine concentration.

Monitoring of nutritional status and suggested frequency^1,2
Laboratory monitoring	Plasma amino acids
Dietary intake; food records	Each clinic visit
Anthropometrics: Growth (weight, length/height, BMI) Waist circumfence from the age of 5 years	Each clinic visit
Clinical examination	Each clinic visit
Plasma homocysteine, methionine and cysteine levels Blau	Plasma amino acids and total homocysteine in infancy every 1-3 months, if indicated even more frequently, later every 3-6 months (Blau)
Vitamin B12 and folate status	Each clinic visit
Essential fatty acids	Annual
Bone mineral density	Once 1-3 years
Cobalamin and folate	Unless on supplementation, serum cobalamin and folate every 3-6 monts
Lipids	Lipids first time at age 2-3 years, afterwards, if naromal, every 2-3 years. If not, every 3 months alongside therapy

Biochemical monitoring in HCU¹
	Plasma methionine	Plasma cysteine	Plasma fHcy*	Plasma tHcy**
B6 responsive	Normal range	Normal range	<10 µmol/l	<50 µmol/l
B6, non responsive, diet alone	Normal range	Normal range	<10 µmol/l	<100 µmol/l
B6 non responsive + betaine	<1000 µmol/l	Normal range	<10 µmol/l	<100 µmol/l

* fHcy:non protein bound homocysteine

* tHcy: plasma total homocysteine

Baric I, Fowler B. Sulphur amino acids. In; Blau N (ed) Physician’s guide to the diagnosis, treatment and follow-up of inherited metabolic diseases, 2^nd Springer Heidelberg, 2014:33-46
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