%0 Journal Article
%T Risk stratification by residual enzyme activity after newborn screening for medium-chain acyl-CoA dehyrogenase deficiency: data from a cohort study
%A Catharina ML Touw
%A G. Peter A Smit
%A Maaike de Vries
%A Johannis BC de Klerk
%A Annet M Bosch
%A Gepke Visser
%A Margot F Mulder
%A M. Estela Rubio-Gozalbo
%A Bert Elvers
%A Klary E Niezen-Koning
%A Ronald JA Wanders
%A Hans R Waterham
%A Dirk-Jan Reijngoud
%A Terry GJ Derks
%J Orphanet Journal of Rare Diseases
%D 2012
%I BioMed Central
%R 10.1186/1750-1172-7-30
%X We performed a retrospective cohort study of all patients identified upon population NBS for MCAD deficiency in the Netherlands between 2007¨C2010. Clinical, molecular, and enzymatic data were integrated.Eighty-four patients from 76 families were identified. Twenty-two percent of the subjects had a variant ACADM genotype. In patients with classical ACADM genotypes, residual MCAD enzyme activity was significantly lower (median 0%, range 0-8%) when compared to subjects with variant ACADM genotypes (range 0-63%; 4 cases with 0%, remainder 20-63%). Patients with (fatal) neonatal presentations before diagnosis displayed residual MCAD enzyme activities <1%. After diagnosis and initiation of treatment, residual MCAD enzyme activities <10% were associated with an increased risk of hypoglycaemia and carnitine supplementation. The prevalence of MCAD deficiency upon screening was 1/8,750 (95% CI 1/7,210¨C1/11,130).Determination of residual MCAD enzyme activity improves our understanding of variant ACADM genotypes and may contribute to risk stratification. Subjects with variant ACADM genotypes and residual MCAD enzyme activities <10% should be considered to have the same risks as patients with classical ACADM genotypes. Parental instructions and an emergency regimen will remain principles of the treatment in any type of MCAD deficiency, as the effect of intercurrent illness on residual MCAD enzyme activity remains uncertain. There are, however, arguments in favour of abandoning the general advice to avoid prolonged fasting in subjects with variant ACADM genotypes and >10% residual MCAD enzyme activity.
%K Population newborn screening
%K Enzyme
%K Genotype
%K Prevalence
%U http://www.ojrd.com/content/7/1/30/abstract