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Diseases Studied

The Rare Diseases Clinical Research Network is an NIH-funded research network of 20 active consortia or research groups working to advance treatment for diseases that are rare. Use the search tools on this page to find the diseases we currently study. You can reach out to the indicated consortia or research groups for more information on those diseases and studies underway.

This network focuses on clinical research and does not generally support clinical care outside of research activities. To learn about other rare diseases, please visit the Genetic and Rare Diseases Information Center (GARD), which is an NIH program that helps the public find reliable information about rare and genetic diseases. Their staff are specialists. Contact them at 1-888-205-2311 or email

All Diseases > STT3A-Congenital Disorder of Glycosylation

STT3A-Congenital Disorder of Glycosylation (STT3A-CDG)

Alternative Names: Congenital Disorder of Glycosylation Iw; CDG Type Iw (CDG-1W or CDG1W); STT3A deficiency

Disease Category: Congenital Disorders of Glycosylation

A rare, multisystemic, inherited condition affecting mainly the neurological system, caused by deficiency of the catalytic subunit of the oligosaccharide protein complex needed for sugar chain transfer to proteins in the endoplasmic reticulum. Symptoms manifest in infancy for the autosomal recessive form and include seizures, developmental delay, and bleeding and clotting problems. In the autosomal dominant form symptoms are more variable but include variable intellectual disability, dysmorphic features, short stature, abnormal bone development, and muscle cramps.

Research groups studying this disease

Congenital Disorders of Glycosylation
FCDGC logo

Frontiers in Congenital Disorders of Glycosylation (FCDGC)


The investigators are conducting a natural history study of patients with congenital disorders of glycosylation (CDG). The study will look into the progression of the disease amongst the participants and also look at the clinical symptoms and how they vary amongst different diseased population groups. The participants will be asked to fill out questionnaires either on their own or with a provider that will grade the severity of disease and document symptoms and diet. Participants will have an opportunity to submit blood, urine, and stool samples that will be tested for biomarkers for CDG. Participants will also complete dietary food records, physical exams, CDG scores, and the PROMIS questionnaires to assess disease progression and severity.

A patient-led infrastructure for research, awareness, and education for Congenital Disorders of Glycosylation.

Promotes awareness of congenital disorders of glycosylation (CDG) and NGLY1-deficiency, provides resources, and funds scientific research.

Connects patients and families affected by congenital disorders of glycosylation (CDG) to clinicians and researchers in Canada and globally.