Background and aims Conotruncal heart defects (CTHD) represent 15–20% of congenital heart defects; common causes are 22q11 microdelection syndrome and other chromosomal rearrangements. Congenital disorders of glycosylation (CDG) are a group of inherited multisystem disorders caused by defective glycosylation of proteins and lipids. Type I CDG is a group of heterogeneous disorders involving defective synthesis or transfer of a lipid-linked oligosaccharide precursor. The most prevalent cardiac abnormalities are cardiomyopathy and pericardial effusion, although CTHD were recently reported in two patients with PMM2-CDG, the most frequent CDG I. We describe a further case of this unusual clinical presentation.

Case report We report a 10 year-old male with neonatal diagnosis of common arterial trunk, repaired at age 17 days. Postoperative course was complicated by cardiopulmonary arrest and allegedly hypoxic ischaemic encephalopathy. He was referred to the paediatric neurology clinic for evaluation of psychomotor delay and epilepsy. Examination at age 2y revealed delayed language, squint and intense hypotonia. Brain MRI revealed cerebral white matter anomalies and cerebellar atrophy, interpreted as result of his hypoxic-ischaemic event. Array-CGH and FISH for 22q11.2 deletion were normal. At age 8y he displayed ataxic gait and dysarthric speech; fat pads and inverted nipples were noted. A repeat MRI showed severe cerebellar atrophy, prompting the suspicion of CDG. Transferrin isoforms analysis showed a typical CDG I pattern. Fibroblast phosphomannomutase activity and PMM2 mutation screen are ongoing.

Conclusions Although cardiomyopathy and pericarditis are common in CDG I, this condition should be suspected in CTHD, particularly when encountering unexpected neurodevelopmental delay.