DOLK-congenital disorder of glycosylation

(often shortened to DOLK-CDG)

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What is DOLK-CDG?

DOLK-congenital disorder of glycosylation (DOLK-CDG, formerly known as congenital disorder of glycosylation type Im) is an inherited condition that often affects the heart but can also involve other body systems. The pattern and severity of this disorder's signs and symptoms vary among affected individuals.

Individuals with DOLK-CDG typically develop signs and symptoms of the condition during infancy or early childhood. Nearly all individuals with DOLK-CDG develop a weakened and enlarged heart (dilated cardiomyopathy). Other frequent signs and symptoms include recurrent seizures; developmental delay; poor muscle tone (hypotonia); and dry, scaly skin (ichthyosis). Less commonly, affected individuals can have distinctive facial features, kidney disease, hormonal abnormalities, or eye problems.

Individuals with DOLK-CDG typically do not survive into adulthood, often because of complications related to dilated cardiomyopathy, and some do not survive past infancy.

How common is DOLK-CDG?

DOLK-CDG is likely a rare condition; at least 18 cases have been reported in the scientific literature.

What genes are related to DOLK-CDG?

DOLK-CDG is caused by mutations in the DOLK gene. This gene provides instructions for making the enzyme dolichol kinase, which facilitates the final step of the production of a compound called dolichol phosphate. This compound is critical for a process called glycosylation, which attaches groups of sugar molecules (oligosaccharides) to proteins. Glycosylation changes proteins in ways that are important for their functions. During glycosylation, sugars are added to dolichol phosphate in order to build the oligosaccharide chain. Once the chain is formed, dolichol phosphate transports the oligosaccharide to the protein that needs to be glycosylated and attaches it to a specific site on the protein.

Mutations in the DOLK gene lead to the production of abnormal dolichol kinase with reduced or absent activity. Without properly functioning dolichol kinase, dolichol phosphate is not produced and glycosylation cannot proceed normally. In particular, a protein known to stabilize heart muscle fibers, called alpha-dystroglycan, has been shown to have reduced glycosylation in people with DOLK-CDG. Impaired glycosylation of alpha-dystroglycan disrupts its normal function, which damages heart muscle fibers as they repeatedly contract and relax. Over time, the fibers weaken and break down, leading to dilated cardiomyopathy. The other signs and symptoms of DOLK-CDG are likely due to the abnormal glycosylation of additional proteins in other organs and tissues.

How do people inherit DOLK-CDG?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of DOLK-CDG?

These resources address the diagnosis or management of DOLK-CDG and may include treatment providers.

You might also find information on the diagnosis or management of DOLK-CDG in Educational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about DOLK-CDG?

You may find the following resources about DOLK-CDG helpful. These materials are written for the general public.

MedlinePlus - Health information (3 links)
Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases
Additional NIH Resources - National Institutes of Health
National Heart, Lung, and Blood Institute: Dilated Cardiomyopathy
Educational resources - Information pages (6 links)
Patient support - For patients and families (5 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

Gene Reviews - Clinical summary
Genetic Testing Registry - Repository of genetic test information (1 link)
ClinicalTrials.gov - Linking patients to medical research
PubMed - Recent literature
OMIM - Genetic disorder catalog

What other names do people use for DOLK-CDG?

CDG1M
congenital disorder of glycosylation, type Im
DK1 deficiency
dolichol kinase deficiency

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about DOLK-CDG?

Ask the Genetic and Rare Diseases Information Center

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding DOLK-CDG?

autosomal ; autosomal recessive ; cardiomyopathy ; cell ; compound ; congenital ; deficiency ;developmental delay ; dilated ; enzyme ; gene ; glycosylation ; hypotonia ; ichthyosis ; inherited ;kidney ; kinase ; muscle tone ; oligosaccharides ; phosphate ; phosphorylation ; protein ; recessive

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (5 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook