• congenital disorder of glycosylation type IIe

This report describes congenital disorders of glycosylation, type IIe (CDG2E; also COG7-CDG), which is a subtype of congenital disorders of glycosylation, type II; CDG2E exhibits autosomal recessive inheritance. The human gene implicated in this disease is COG7, which is a component of the conserved oligomeric Golgi (COG) complex and plays a role in retrograde Golgi transport. There is a single high-scoring fly ortholog, Cog7, for which missense alleles, RNAi targeting constructs, and an allele caused by insertional mutagenesis have been generated.

A UAS construct of a wild-type tagged human Hsap\COG7 gene has been introduced into flies, but has not been characterized.

Animals homozygous for loss-of-function mutations of Dmel\Cog7 are viable, but have decreased adult lifespan and locomotor defects; males are sterile. In mutant spermatocytes, the morphology of the Golgi stacks is severely disrupted; the majority of spermatids are multinucleate, suggesting a failure of meiotic cytokinesis. In larvae homozygous for loss-of-function mutations, mild defects in cytokinesis are seen in neuroblasts in the brain; anatomical defects are observed for larval neuromuscular junctions. Changes in the repertoire of N-glycans have been assessed in mutant animals. A small number of physical interactions have been described for Dmel\Cog7; see below and in the Cog7 gene report.

[updated Jan. 2018 by FlyBase; FBrf0222196]