Deficiency of Subunit 6 of the Conserved Oligomeric Golgi Complex (COG6-CDG): Second Patient, Different Phenotype

We describe a 27-month-old girl with COG6 deficiency. She is the first child of healthy consanguineous Moroccan parents. She presented at birth with dysmorphic features including microcephaly, post-axial polydactyly, broad palpebral fissures, retrognathia, and anal anteposition. The clinical phenotype was further characterised by multiorgan involvement including mild psychomotor retardation, and microcephaly, chronic inflammatory bowel disease, micronodular liver cirrhosis, associated with life-threatening and recurrent infections due to combined T- and B-cell dysfunction and neutrophil dysfunction. Mutation analysis showed the patient to be homozygous for the c.G1646T mutation in the COG6 gene. She is the second reported patient with a deficiency of subunit 6 of the COG complex. Although both patients are homozygous for the same mutation, they present a markedly different clinical picture. Indeed immunodeficiency as well as inflammatory bowel disease has not been described previously in patients with any COG-CDG.