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NGLY1 deficiency (NORD)



Patient care

Information for patients and families

The Primary School
Glut1 Deficiency Foundation
The National Organization for Rare Disorders (NORD)
Narcolepsy (NORD)
Adrenoleukodystrophy (NORD)
Zellweger spectrum disorders (NORD)
Glycogen storage disease type II (NORD)
Metachromatic leukodystrophy (NORD)
Gaucher disease (NORD)
Niemann-Pick disease types A and B (NORD)
Fabry disease (NORD)
Tay-Sachs disease (NORD)
Mucopolysaccharide storage disease type 1 (Hurler syndrome) (NORD)
Mucopolysaccharide storage disease type 2 (Hunter syndrome) (NORD)
Phenylketonuria (NORD)
Cystinuria (NORD)
Aromatic L-amino acid decarboxylase deficiency (NORD)
Cerebrotendinous xanthomatosis (NORD)
Classical homocystinuria (NORD)
Autoimmune polyglandular syndrome type 1 (NORD)
Thyroid eye disease (NORD)
Opsoclonus myoclonus syndrome (NORD)
Thyroid eye disease (NORD)
Short bowel syndrome (NORD)
Bile synthesis disorders (NORD)
Eosinophilic esophagitis (NORD)
Cyclic vomiting syndrome (NORD)
Polycythemia vera (NORD)
Essential thrombocythemia (NORD)
Myelofibrosis (NORD)
Warm autoimmune hemolytic anemia and cold agglutinin (NORD)
Sickle cell disease (NORD)
Waldenstrom macroglobulinemia (NORD)
Post-transplant lymphoproliferative disorders (NORD)
Cytomegalovirus infection after transplant (NORD)
Congenital athymia (NORD)
Severe chronic neutropenia (NORD)
Mycobacterium avium complex (NORD)
Congenital cytomegalovirus (NORD)
Opsoclonus myoclonus syndrome (NORD)
Spinocerebellar ataxia (NORD)
Early infantile epileptic encephalopathy (NORD)
IgA nephropathy (NORD)
Focal segmental glomerulosclerosis (NORD)
Alagille syndrome (NORD)
NGLY1 deficiency (NORD)
PIK3CA-related overgrowth spectrum (NORD)
Recurrent pericarditis (NORD)
Gorlin Syndrome Alliance

Content Reviewers:

Kelly Johnson, MS

NGLY1 deficiency is a rare genetic disorder affecting multiple parts of the body due to a deficiency of the enzyme N-glycanase.

Enzymes are proteins which help speed up chemical reactions in the body and N-glycanase speeds up the removal of sugar chains from proteins.

Without this process, proteins do not function normally and misshaped ones may accumulate. NGLY1 deficiency is a chronic condition that presents during infancy and early childhood.

NGLY1 deficiency has a number of characteristic symptoms, although the specific symptoms a patient experiences are often unique to the individual.

Most infants and children with NGLY1 deficiency do not grow or develop as expected. Symptoms may include low birthweight, a smaller than expected head circumference, and missing developmental milestones, such as walking or talking.

Intellectual disability is also common. Many affected individuals have motor problems including shaking and uncontrollable movements, which can range from slight tremors while trying to do fine motor skills like writing, to an uncontrolled sometimes painful jerky movement.

Skeletal abnormalities may also occur such as small hands or feet, frequently broken bones, uneven shoulders or hips, difficulty standing up straight, and dislocated joints.

Some patients develop seizures which can start as early as two months of age. Individuals with NGLY1 deficiency often will not produce tears when crying.

This in turn may cause other complications, such as scarring and ulcers in the eyes, painful or irritated eyes, and poor vision. Lastly, liver problems may arise in children with NGLY1 deficiency.

NGLY1 deficiency is caused by changes or mutations in the NGLY1 gene, and follows an autosomal recessive inheritance pattern.

This means that both copies of the NGLY1 gene must be mutated for an individual to have the disorder. The mutated NGLY1 gene causes the N-glycanase enzyme to be dysfunctional or be completely absent.

N-glycanase’s role is to speed up the process of removing sugar molecules from proteins. Removing sugar molecules from damaged proteins allows them to be recycled.


N-glycanase 1 deficiency, also known as NGLY1 deficiency, is a rare genetic disorder characterized by a deficiency of the enzyme N-glycanase 1 (NGLY1). NGLY1 is involved in the breakdown of complex sugars known as N-glycans attached to proteins throughout the body.

NGLY1 deficiency results from a mutation in the NGLY1 gene that decreases NGLY1 production. Symptoms include developmental delays, intellectual disability, seizures, delayed developmental milestones, as well as problems with movement and coordination. They may also have abnormalities of the eyes, including cataracts and problems with eye movement.