Clinical Indications and Outcome of Biotinidase Deficiency Screening among Children and Youths in a Scottish NHS Region Between 2014 and 2016

Biotinidase deficiency (BTD) is an autosomal recessive metabolic disorder characterized by neurodevelopmental and cutaneous disorders. Individuals with BTD have either homozygous or compound heterozygous variants of biotinidase (BT) enzyme. We aimed to analyse the pattern and outcome of investigations for BTD among children and young people in a Scottish NHS Board. We retrospectively analysed the clinical and laboratory data of all children within the Fife area who were screened for BTD between July 2014 and July 2016. BTA levels ranged between 2.7 and 14.1 nmol/min/mL from a total of 191 patients. 262 tests were requested for 243 children aged between 1 month and 17 years-6 months (Mean 70 months). 75 of the samples (29%) were ordered to be repeated. 59 samples from 53 patients (22%) could not be analysed for reasons including ―insufficient sample‖ (34), ―unsuitable bottle‖ (10), ―missed in error‖ (7), and ―samples leaked in transit‖ (3). The commonest indications for BTD screening were developmental delay (63%) and social communication concerns (49%). The majority (93%) of the tests were requested by either the Consultant or Specialist Community Child Health (CCH) Paediatricians. None of the 191 patients analysed had BTD. However a substantial proportion of the patients (22%) could not be analysed due to various problems with their blood samples. This study has practical implications for routine clinical care and investigation for children and young people with Developmental or Learning Disabilities. A larger prospective study is required to verify the true prevalence of BTD in the population.