Congenital disorder of glycosylation (CDDG)

What is Congenital disorder of glycosylation (CDDG)?

This genetic condition is also be known as deficiency of N-glycanase 1.

This deficiency of NGLY1 is believed to trigger many of the symptoms associated with this syndrome.

These symptoms include development delay, seizures and uncontrolled limb movements.

What gene changes cause Congenital disorder of glycosylation (CDDG)?

Mutations in the NGLY1 gene are responsible for the syndrome. It is inherited in an autosomal recessive pattern.

Autosomal recessive inheritance means an affected individual receives one copy of a mutated gene from each of their parents, giving them two copies of a mutated gene. Parents, who carry only one copy of the gene mutation will not generally show any symptoms, but have a 25% chance of passing the copies of the gene mutations onto each of their children.

What are the main symptoms of Congenital disorder of glycosylation (CDDG)?

Symptoms may vary widely between individuals affected with the syndrome.

Symptoms usually start to present during infancy with delayed speech, delayed motor skills (walking, sitting, crawling) and hypotonia (low muscle tone).

Individuals may also experience uncontrollable limb movements and seizures that don’t always respond to treatment.

Symptoms related to the eyes include optic atrophy, changes or damage to the retina, and an absence of tears.

Other features include a very small head (microcephaly), seizures and abnormal liver function.

How does someone get tested for Congenital disorder of glycosylation (CDDG)?

The initial diagnosis of Congenital disorder of deglycosylation can begin with facial genetic analysis screening, as offered by FDNA Telehealth, which can identify the key markers of the syndrome and outline the need for further testing. If further testing is recommended what will follow is a consultation with a genetic counselor and then a geneticist. These consultations will usually involve a comprehensive review of the patient’s medical history, a generational family history documenting health issues and genetic conditions, and a detailed physical examination. Based on this clinical consultation, the options and recommendations for genetic testing will be shared with the individual’s parents/guardians and consent will be sought for further testing. This process may take place over the course of several clinic visits. Genetic testing will involve a blood sample. Results from the testing will then be sent back to the geneticist who will explain the resulting report in detail with the parents/guardians of the individual being tested.

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