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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 > PMM2-Congenital Disorder of Glycosylation

PMM2-Congenital Disorder of Glycosylation (PMM2-CDG)

Alternative Names: Congenital Disorder of Glycosylation Type Ia; Jaeken syndrome (CDG1A)

Disease Category: Congenital Disorders of Glycosylation

The most common, yet rare, congenital disorder of glycosylation. Symptoms manifest in infancy, including hypotonia (low muscle tone), abnormal fat distribution, strabismus (crossed eyes), developmental delay, failure to thrive, hydrops fetalis (abnormal fluid build-up), intellectual disability, temporary paralysis, peripheral neuropathy, kyphoscoliosis (abnormal curvature of the spine), ataxia (impaired balance or coordination), joint contractures, vision loss, and facial dysmorphism (abnormal difference in structure).

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.

This study is double-blind, placebo-controlled, 1:1 randomized clinical therapeutic trial of acetazolamide for the treatment of ataxia in patients with PMM2-CDG. Clinical history and screening data will be reviewed to determine subject eligibility. Potential subjects who have a molecularly and/or biochemical confirmed diagnosis of PMM2-CDG will be consented. Baseline data will be collected prior to randomization and at treatment initiation. Subjects who meet all inclusion criteria and none of the exclusion criteria will be enrolled into the study. Each subject who meets all the inclusion and none of the exclusion criteria will then be randomized to placebo or acetazolamide. They will be administered weight-dependent doses of acetazolamide or an equivalent volume of placebo twice daily by mouth. Enrollment will be open to individuals with a diagnosis of PMM2-CDG, 4 years and older. The trial will be performed at Seattle Children’s Hospital (Dr. Irene Chang and Dr. Christina Lam), Children’s Hospital of Philadelphia (Dr. Andrew Edmondson), and Mayo Clinic (Dr. Eva Morava-Kozicz).

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.

Funds research for congenital disorders of glycosylation (CDG), advocates for screening, raises awareness, and assists families.

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