Nutritional management of Very long chain acyl-CoA dehydrogenase deficiency (VLCAD)

Ashleigh Mitchell1, Sue Thompson1, Sarah Slack1, Kaustuv Bhattacharya2

1 Department of Nutrition and Dietetics, The Children’s Hospital Westmead, Sydney, Australia

2 Genetic Metabolic Disorders Service, The Children’s Hospital Westmead, Sydney, Australia

Corresponding author contact information:

Ashleigh Mitchell Ashleigh.mitchell@health.nsw.gov.au Mob: +614 04 982 921

Expanded newborn screening (NBS) has resulted in identification of patients with VLCAD that are asymptomatic at time of diagnosis. The variability of phenotypes within the condition and limited genotype, phenotype correlation has complicated nutritional management. Furthermore, the rarity of the condition has made evidenced based studies difficult and prompted consensus workshops to guide therapy. Our aim was to examine nutritional management of children with VLCAD using a retrospective audit conducted January 2016. Eighteen patients were

identified (15 diagnosed by NBS/symptomatic at birth, 3 diagnosed between 1 and 11 years old). In infancy, medium chain triglyceride (MCT) based formula was recommended for 13 patients, providing ~30% (n=8), 50% (n=4)

or 70% (n=1) of energy intake, depending on initial feeding method and clinical assessment. Two received long chain triglyceride (LCT) based formula alone. Introduction to food education aimed to achieve <10% (n=11),

10-20% (n= 4) or <30% (n=3) energy from LCTs with MCT medical foods as an energy source. Triheptanoin was used by 2 patients. Maximum fasting duration was a median of 4 hours at diagnosis, 6 hours at 6 months and 8 hours at 12 months of age. Unwell recommendations increased proportion of MCT formula/ medical food with addition of a carbohydrate source in most cases (n=12). Two patients required gastrostomy placement.

Essential fatty acid supplements were prescribed only with biochemically evident deficiency (n=7).

Further studies quantifying LCT intake compared to prescribed diet and subsequent correlation with phenotype expression are required.