Delineating the patient population with Medium chain acyl-CoA dehydrogenase deficiency (MCADD): British Columbia Children’s Hospital (BCCH) clinic experience.

Kathleen Duddy RN, MSN, CPNP (P)¹, Ramona Salvarinova MD, FRCPC, FCCMG^1*, Graham Sinclair PhD FCCMG², Sylvia Stockler MD, PhD, MBA, FRCPC¹

1Division of Biochemical Diseases, Department of Pediatrics BC Children’s Hospital, Vancouver Canada

2Department of Pathology and Laboratory Medicine, BC Children’s Hospital, Vancouver, Canada

Keywords: Medium chain acyl-CoA dehydrogenase deficiency, l-carnitine, free carnitine, newborn screening, variants,

Background: Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is a rare genetic disorder, and the most common fatty acid oxidation disorder occurring 1 in 12000 births in British Columbia (BC). MCADD has been part of the new born screening (NBS) program in BC since 2002. Following confirmation of the newborn screening for MCADD, targeted genetic testing for the common two mutations in the ACADM gene is performed. Full gene sequencing is undertaken for patients where one or no common mutation is detected. We currently follow 50 patients with MCADD, age 4 weeks to 14 years. While initially all MCADD patients were started on L-Carnitine at birth, the practice was changed in 2013 supplementing only patients with below the normal free carnitine levels.

Methods: Chart review was performed and information on several parameters was obtained: molecular results, patients started on L-carnitine at birth, carnitine supplementation including dosage and f ree carnitine levels.

Results: The clinic follows 50 patients; 28 are homozygous for the common c.985A>G variant, and 4 patients are compound heterozygous for the c.985A>G and c.199T>G variant. Currently 37 patients are supplemented with L-Carnitine; dose ranging from 13 to 105 milligram/kilogram/day (mean of 43 milligram/kilogram/day). 7 patients were not started on L-carnitine at birth and maintained normal free carnitine level on follow up. With the change in practice 18 patients stopped L-carnitine, 11 of which required restarting supplementation.

Summary: The MCADD patients differ in their need for carnitine supplementation. Further delineation of factors influencing this, including genotype correlation will be performed.