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General Information
Name
congenital disorder of glycosylation, type IIe
FlyBase ID
FBhh0000711
Overview

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]

Disease Summary Information
Parent Disease Summary: congenital disorders of glycosylation, type II
Symptoms and phenotype
Specific Disease Summary: congenital disorder of glycosylation, type IIe
OMIM report

[CONGENITAL DISORDER OF GLYCOSYLATION, TYPE IIe; CDG2E](https://omim.org/entry/608779)

Human gene(s) implicated

[COMPONENT OF OLIGOMERIC GOLGI COMPLEX 7; COG7](https://omim.org/entry/606978)

Symptoms and phenotype

Common features of Golgi-complex-related glycosylation disorders (COG-CDG) are feeding problems, growth retardation, microcephaly, dysmorphism, hypotonia, and cerebral atrophy. COG7-deficiency is a lethal disorder with additional characteristics of hyperthermia, ventricular/atrial septal defect, and cholestatic liver disease. [from Jaeken, 2013; pubmed:23622397, FBrf0229305]

Genetics

Congenital disorder of glycosylation type IIe (CDG2E) is caused by homozygous mutation in the gene encoding COG7 (component of oligomeric Golgi complex-7). [from OMIM:608779; 2018.01.25]

Cellular phenotype and pathology
Molecular information

The protein encoded by COG7 is one of the 8 subunits of the conserved oligomeric Golgi (COG) complex, which is required for normal Golgi morphology and localization. [Gene Cards, COG7; 2018.01.25]

The oligomeric Golgi complex is thought to play a critical role in vesicle tethering processes involving retrograde Golgi transport of resident proteins responsible for glycan biosynthesis (Jaeken, 2013; pubmed:23622397, FBrf0229305).

Down-regulation of COG function results in the resident Golgi glycosyltransferases/glycosidases to be mislocalized or degraded (Smith and Lupashin, 2008; pubmed:18353293).

External links
Disease synonyms
CDG2E
CDGIIe
CDG IIe
COG7-CDG
COG-CDG
Ortholog Information
Human gene(s) in FlyBase
Human gene (HGNC)
D. melanogaster ortholog (based on DIOPT)
Comments on ortholog(s)

One to one (1 human to 1 Drosophila)

Other mammalian ortholog(s) used
    D. melanogaster Gene Information (1)
    Molecular function (GO)
      Gene Groups / Pathways
      Comments on ortholog(s)

      High-scoring ortholog of human COG7 (1 Drosophila to 1 human); Dmel\Cog7 shares 28% identity and 46% similarity with the human gene.

      Orthologs and Alignments from DRSC
      DIOPT - DRSC Integrative Ortholog Prediction Tool - Click the link below to search for orthologs in Humans
      Other Genes Used: Viral, Bacterial, Synthetic (0)
        Summary of Physical Interactions (4 groups)
        protein-protein
        Interacting group
        Assay
        References
        pull down, western blot, anti tag western blot
        pull down, anti tag western blot, western blot
        two hybrid, proximity ligation assay, fluorescence microscopy, pull down, western blot, anti tag coimmunoprecipitation
        two hybrid, anti tag coimmunoprecipitation, anti tag western blot, western blot
        Alleles Reported to Model Human Disease (Disease Ontology) (2 alleles)
        Models Based on Experimental Evidence ( 2 )
        Modifiers Based on Experimental Evidence ( 0 )
        Allele
        Disease
        Interaction
        References
        Alleles Representing Disease-Implicated Variants
        Genetic Tools, Stocks and Reagents
        Sources of Stocks
        Contact lab of origin for a reagent not available from a public stock center.
        Bloomington Stock Center Disease Page
        Selected mammalian transgenes
        Allele
        Transgene
        Publicly Available Stocks
        Selected Drosophila transgenes
        Allele
        Transgene
        Publicly Available Stocks
        RNAi constructs available
        Allele
        Transgene
        Publicly Available Stocks
        Selected Drosophila classical alleles
        Allele
        Allele class
        Mutagen
        Publicly Available Stocks
        References (7)