A new mutation in COG7 extends the spectrum of COG subunit deficiencies

We describe a patient homozygous for a novel mutation in COG7, coding for one of the subunits of the Conserved Oligomeric Golgi complex, involved in retrograde vesicular trafficking. His brother showed a similar clinical syndrome and glycosylation defect but no DNA could be obtained from this patient. This mutation, c.170-7A > G, activates a cryptic splice acceptor and leads to the insertion of 2 amino acids at protein level (p.56-57insAT). The insertion disturbs the structure and function of the Conserved Oligomeric Golgi complex. In comparison to the previously described patients with a different COG7 mutation, intrauterine growth retardation and dysmorphic features were absent and there was a longer survival.