Congential disorders of glycosylation

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Inclusion Criteria

  • Repeated abnormal pattern on transferrin isolelectric focussing in a child of >3 months, AND
  • Clinically multisystem disease with abnormal protein C and / or S; AND Factor VIII and/or factor XI and /or ATIII (abnormal)
  • OR
    Muscle biopsy with abnormal dystroglycan pattern
  • OR
    Normal transferrin isolelectric focussing but patient thought to have CDG after assessment by metabolic or neurometabolic specialist and exclusion of abnormalities of VLCFA or 7DHC

Exclusion Criteria

  • Known genetic cause

Prior genetic testing guidance

  • Results should have been reviewed for all genetic tests undertaken, including disease-relevant genes in exome sequencing data. The patient is not eligible if they have a molecular diagnosis for their condition.
  • Genetic testing should continue according to routine local practice for this phenotype regardless of recruitment to the project; results of these tests must be submitted via the ‘Genetic investigations’ section of the data capture tool to allow comparison of WGS with current standard testing.

PLEASE NOTE: The sensitivity of WGS compared to current diagnostic genetic testing has not yet been established. It is therefore important that tests which are clinically indicated under local standard practice continue to be carried out.

Prior genetic testing genes 

Testing of the following genes should be carried out PRIOR TO RECRUITMENT where this is in line with current local practice:

  • Transferrin isoelectric focussing and, if abnormal, confirmed on a second sample and PMM2 deficiency excluded
  • Those with normal IEF should be assessed by metabolic or neurometabolic specialist for inclusion; 7DHC should be normal; VLCFA should be normal; protein C and S, factor VIII and XI and ATIII, T4 and TSH should be measured; for suspected isolated O glycosylation or combined N- and O-glycosylation defect ApoC III should be measured.

Closing Statement:

These requirements will be kept under continual review during the Main Programme and may be subject to change.

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