Objectives: This study aimed to increase the number of treatable disorders screened by the Mass Urinary Screening Program in the Province of Quebec and the Territory of Nunavut. Creatine synthesis and transport disorders, Triple H syndrome and ornithine transcarbamylase deficiency were targeted by selecting specific biomarkers: creatine, guanidineacetic acid, uracil, orotic acid and creatinine in urine filter paper samples. Method: A 5-cm filter paper (Whatman-GE) disk was punched out, and extracted with 3 mL of 0.01 M NH 4 OH/H 2 O by rotary shaking for 10 min. Twenty microliters of the extracts were combined to 20 mL of the internal standards, followed by addition of 250 mL ACN:MeOH. Samples were vortexed, centrifuged, and the extracts injected into a UPLC-Xevo TQ-S tandem MS system (Waters Corp.). Results: A rapid 2-minute high-throughput multiplex MS method- ology was devised using positive and negative electrospray ionization modes. Validation of the methodology showed good precision and accuracy for the intraday and interday assays (less than 15%). The linearity was good for each molecule with a mean (n = 5) coefficient of regression at 0.999 for uracil and 0.998 for creatinine, guanidineacetic acid, creatine, and orotic acid. Urine specimens from affected patients revealed positive abnormal results. Conclusion: This methodology demonstrates the feasibility of mass or high-risk screening urine samples for early, pre-symptomatic detection and treatment of these rare diseases. doi:10.1016/j.clinbiochem.2014.07.067 Molecular, biochemical and clinical heterogeneity in very-long-chain acyl-CoA dehydrogenase deficiency in the Canadian Maritime Provinces Jane Gillis a, b , David Skidmore a, b , Heather McDonald a , Joan Farrel a , Maggie Chapman a , Nelofar Kureshi a , Sarah Dyack a, b a Maritime Medical Genetics Service, IWK Health Centre, Halifax, NS, Canada b Department of Pediatrics, Dalhousie University, Halifax, NS, Canada Background: Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD, MIM #201475) is a rare autosomal recessive disorder of fatty acid metabolism caused by mutations in the ACADVL gene. The disorder is classified into three forms, infantile, childhood and adult, depending on the time of onset and severity of illness. Early detection through newborn screening programs allows for favorable clinical outcomes primarily through the avoidance of fasting and treatment of fasting illnesses with IV dextrose. Methods: After identification via abnormal newborn screen, diagnosis is established through: acylcarnitine analysis by MS–MS of plasma or a dried blood spot specimen, molecular genetic analysis, and measurement of residual enzyme activity in lymphocytes. Results: Molecular and enzymatic results do not routinely provide clinicians with the ability to accurately predict the form and therefore severity of this disorder in asymptomatic patients. Since screening for VLCADD began in Nova Scotia in 2002, the incidence of VLCADD is greater in the Maritimes than the approx- imated 1 in 30,000 quoted in the literature. We have also identified a common novel mutation in symptomatic VLCADD patients of Acadian ancestry. Conclusion: The incidence of VLCADD in Maritime Canada is higher than that reported in the literature. We have identified a novel ACADVL mutation in the Acadian population that is associated with the development of hypoglycemia that may account in some part for the high number of affected patients. A better understanding of the genotype–phenotype relationship in VLCADD in our patient population would be helpful in the prediction of cardiac, hepatic and metabolic complications. doi:10.1016/j.clinbiochem.2014.07.068 In the loop: Primary care providers' role in newborn screening for cystic fibrosis Robin Z. Hayeems a, b , Fiona A. Miller b , Carolyn J. Barg b , Yvonne Bombard b, c , Peter Durie d , Pranesh Chakraborty f, g , Beth K. Potter h , Jessica P. Bytautas i , Karen Tam j , Louise Taylor k , Elizabeth Kerr l , Christine Davies f , Jennifer Milburn f , Katherine Keenan d , Felix Ratjen d, e, k , Astrid Guttmann b, d, e, m , June C. Carroll n a Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada b Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario, Canada c Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada d Division of Paediatric Medicine, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada e Department of Paediatrics, Faculty of Medicine, University of Toronto, Ontario, Canada f Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada g Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada h Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada i Division of Health Care and Outcomes Research, Toronto Western Research Institute, Toronto, Ontario, Canada j Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada k Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada l Department of Psychology, The Hospital for Sick Children, Toronto, Ontario, Canada m Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada n Department of Family and Community Medicine, Mount Sinai Hospital, University of Toronto, Ontario, Canada Objectives: Expanded newborn screening (NBS) has increased the number of positive screening results, prompting attention to the role of primary care providers (PCP) in informing and supporting families. We explored PCPs' reported and expected role in NBS for CF and parents' experiences with result notification. Methods: As part of a mixed-methods cohort study of mothers' experiences with NBS for CF, we surveyed mothers of infants who screened positive for CF about the role of PCPs in notification. Ontario PCPs who had a positive CF NBS result in the previous 6 months were also invited to complete a questionnaire and an interview. Results: 329 of 653 PCPs (50%) completed surveys, as did 146 of 257 mothers (57%); 38 PCPs participated in interviews. A majority (n = 266, 81%) of PCPs agreed that they have an important role in NBS. For the recent CF NBS infant in their care, the majority reported having notified the family (65%; vs notification by treatment centre), and having discussed results of confirmatory testing (77%). Qualitatively, PCPs reported a desire to be informed about screening and confirmatory results, regardless of role in notification. 56% of mothers were notified of their infants' positive CF NBS result by their PCP; of these, only 12% would have preferred otherwise. Abstracts 147