Carnitine palmitoyl transferase (CPT) 1 A deficiency
is a rare disorder of hepatic long-chain fatty acid
oxidation. CPT1 deficiency is included in newborn screening
programs in a number of countries to allow presymptomatic
detection and early treatment of affected patients.
We present a case of presymptomatic CPT1A deficiency
detected through newborn screening in Denmark with
diagnostic levels of carnitine and acylcarnitines in the
initial dried blood spot. Levels of plasma-free carnitine and
acylcarnitines in follow-up samples were normal, but
reverted to diagnostic levels when the patient developed
clinical symptoms at the age of 8 months. At that time,
a diagnosis of CPT1A deficiency was confirmed by
sequence analysis of the CPT1A gene revealing homozygosity
for a novel c.167C>T variation in exon 3. Enzyme
activity measurements showed a relatively mild enzyme
defect with a decreased residual enzyme activity of
17–25%. We conclude that CPT1A gene testing and/or
enzyme assay is mandatory to confirm an abnormal newborn
screen suggesting CPT1A deficiency to avoid delayed
diagnoses.