CCDC115-CDG
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Also known as: Congenital Disorder of Glycosylation Type IIo, CDG-IIo
At a Glance
What is CCDC115-CDG?
CCDC115-CDG is a rare genetic disorder that affects the body's ability to properly glycosylate proteins, which is essential for normal function of many body systems. It primarily impacts the liver and can lead to liver disease, but it may also affect other organs such as the heart and brain. The condition is caused by mutations in the CCDC115 gene, leading to defective protein glycosylation. Symptoms often begin in infancy and can include developmental delays, liver dysfunction, and failure to thrive. As the disorder progresses, individuals may experience more severe symptoms such as neurological issues and organ failure. Early diagnosis is crucial to manage symptoms and improve quality of life. The condition can place a significant emotional and financial burden on families, as ongoing medical care and support are often required. Prognosis varies depending on the severity of symptoms and the effectiveness of management strategies. Daily life for affected individuals may involve frequent medical appointments, specialized therapies, and dietary modifications. Support from healthcare providers and patient communities can be invaluable for families navigating this condition. Research into potential treatments and therapies is ongoing, offering hope for improved outcomes in the future.
Medical Definition
CCDC115-CDG is a congenital disorder of glycosylation characterized by defective N-linked glycosylation due to mutations in the CCDC115 gene. Pathologically, it involves abnormal glycosylation of serum and cellular proteins, leading to multisystemic involvement. Histological findings may include liver fibrosis and steatosis, as well as potential neurological tissue abnormalities. It is classified under CDG Type II disorders, which are characterized by defects in the processing of protein-bound glycans. Epidemiologically, it is an extremely rare condition with a prevalence of approximately 1 in 1,000,000. The disease course can vary widely, with some patients experiencing severe, life-threatening complications while others have milder symptoms.
CCDC115-CDG Symptoms
Symptoms vary in severity between individuals. Early diagnosis and management can significantly improve outcomes.
Very Common
Liver dysfunction in CCDC115-CDG often presents as hepatomegaly and elevated liver enzymes. This is caused by impaired glycosylation affecting liver cell function and structure. Over time, liver dysfunction can progress to fibrosis or cirrhosis if not managed. Patients may experience fatigue, jaundice, and abdominal discomfort, and management includes regular monitoring and supportive care.
Developmental delay manifests as slower achievement of motor, cognitive, and social milestones. It results from the impact of glycosylation defects on neurological development. The delay may become more apparent as the child grows, affecting school performance and social interactions. Early intervention with therapies can help improve developmental outcomes.
Failure to thrive is characterized by poor weight gain and growth in infants and children. This occurs due to metabolic imbalances and nutritional deficiencies linked to glycosylation defects. As the condition progresses, it can lead to stunted growth and developmental issues. Nutritional support and monitoring are crucial to manage this symptom effectively.
Common
Recurrent infections occur due to compromised immune function associated with glycosylation disorders. The immune system's ability to respond to pathogens is impaired, leading to frequent illnesses. Over time, these infections can lead to complications and hospitalizations. Preventive measures and prompt treatment of infections are essential to reduce their impact.
Hypotonia, or decreased muscle tone, presents as muscle weakness and floppiness. It is caused by neurological impairment due to defective glycosylation. Hypotonia can affect motor development and physical activities, making daily tasks challenging. Physical therapy can help improve muscle strength and coordination.
Coagulopathy in CCDC115-CDG is characterized by bleeding tendencies due to impaired blood clotting. This results from abnormal glycosylation of clotting factors. Over time, patients may experience easy bruising, nosebleeds, or prolonged bleeding from minor injuries. Regular monitoring and appropriate treatment can help manage bleeding risks.
Less Common
Cardiomyopathy presents as heart muscle weakness, leading to reduced cardiac output. It is caused by glycosylation defects affecting cardiac muscle cells. Over time, this can progress to heart failure if not managed. Regular cardiac evaluations and medications can help manage symptoms and improve heart function.
Seizures in CCDC115-CDG manifest as episodes of abnormal electrical activity in the brain. They are caused by neurological disturbances due to defective glycosylation. Seizures can vary in frequency and severity, impacting daily life and safety. Anti-seizure medications and regular neurological assessments are important for management.
What Causes CCDC115-CDG?
CCDC115-CDG is caused by mutations in the CCDC115 gene, located on chromosome 2q21. The CCDC115 gene encodes a protein that is part of the vacuolar H+-ATPase (V-ATPase) complex, which is essential for acidifying intracellular compartments. Mutations in CCDC115 lead to structural changes in the protein, impairing its ability to integrate into the V-ATPase complex. This disruption results in defective acidification of the Golgi apparatus and lysosomes, crucial for proper protein processing and trafficking. Consequently, there is an accumulation of misfolded glycoproteins and impaired glycosylation, affecting cellular function. The dysfunction of the Golgi and lysosomes leads to widespread cellular stress and apoptosis, particularly affecting hepatocytes and neurons. The immune system may respond to this cellular damage with neuroinflammation, exacerbating neuronal injury. Over time, the degeneration of white matter and other neural structures occurs due to chronic cellular stress and inflammation. Symptoms manifest as liver disease, neurodevelopmental delay, and hypotonia, reflecting the tissues most reliant on glycosylation. The variability in disease severity among patients is attributed to the specific nature of the mutations and their impact on residual protein function. Some mutations may allow partial V-ATPase activity, resulting in milder phenotypes. Additionally, genetic background and environmental factors may influence the clinical presentation. The pattern of symptoms is determined by the differential vulnerability of tissues to glycosylation defects and cellular stress. Understanding these molecular mechanisms is crucial for developing targeted therapies for CCDC115-CDG.
How is CCDC115-CDG Diagnosed?
Typical age of diagnosis: CCDC115-CDG is typically diagnosed in infancy or early childhood when symptoms such as liver dysfunction and developmental delays become apparent. Diagnosis often follows a period of clinical observation and symptom progression, prompting further investigation. Early recognition is crucial for management and genetic counseling. The condition is confirmed through a combination of clinical, laboratory, and genetic evaluations.
Clinicians look for signs of liver dysfunction, developmental delays, and failure to thrive. A detailed family history is important to identify any hereditary patterns or similar conditions. Physical examination may reveal hepatomegaly, hypotonia, and dysmorphic features. This step helps determine the need for further diagnostic testing and guides the clinical suspicion towards a congenital disorder of glycosylation.
Ultrasound is commonly used to assess liver size and structure. Specific abnormalities such as hepatomegaly and liver texture changes can be visible. These findings support the diagnosis of a liver-related disorder and help exclude other conditions like biliary atresia. Imaging results, combined with clinical findings, strengthen the suspicion of CCDC115-CDG.
Serum transferrin isoelectric focusing is ordered to detect glycosylation abnormalities. Abnormal transferrin patterns indicate a type II congenital disorder of glycosylation. Elevated liver enzymes and abnormal coagulation profiles may also be present. Laboratory results guide the need for genetic testing and further metabolic workup.
The CCDC115 gene is sequenced to identify pathogenic mutations. Common mutations include missense and nonsense variants that disrupt protein function. Genetic testing confirms the diagnosis by identifying biallelic mutations in CCDC115. Results are crucial for genetic counseling and assessing recurrence risk in future pregnancies.
CCDC115-CDG Treatment Options
Galactose therapy is used to improve glycosylation defects. It works by providing a substrate for glycan synthesis, potentially improving protein glycosylation. Clinical evidence shows variable efficacy, with some patients experiencing improved liver function and growth. Limitations include the need for close monitoring of galactose levels and potential side effects like diarrhea. Long-term benefits and risks are still being studied.
Techniques such as motor skill exercises and occupational therapy are employed. The goal is to improve muscle tone, coordination, and developmental milestones. Sessions are typically conducted several times a week, lasting 30-60 minutes each. Measurable outcomes include improved motor skills and increased independence in daily activities. Long-term benefits include enhanced quality of life and reduced disability.
Indicated for severe liver dysfunction unresponsive to medical therapy. The procedure involves replacing the diseased liver with a healthy donor liver. Expected benefits include improved liver function and overall health. Surgical risks include rejection, infection, and complications from immunosuppression. Post-operative care requires lifelong monitoring and medication adherence.
The team includes hepatologists, geneticists, dietitians, and therapists. Interventions focus on managing symptoms, nutritional support, and developmental therapies. Psychosocial support strategies involve counseling and support groups for families. Family education is provided on disease management and genetic implications. Long-term monitoring includes regular follow-ups and adjustment of care plans as needed.
When to See a Doctor for CCDC115-CDG
- Severe jaundice — indicates liver dysfunction and requires immediate medical attention.
- Acute abdominal pain — could signify liver complications or other serious issues.
- Sudden loss of consciousness — may indicate severe metabolic imbalance or neurological involvement.
- Persistent vomiting — may lead to dehydration and requires medical evaluation.
- Unexplained weight loss — could indicate malabsorption or metabolic issues, warranting further investigation.
- Chronic fatigue — may be a sign of liver dysfunction or other systemic issues, and should be discussed with a healthcare provider.
- Mild fatigue — monitor energy levels and ensure adequate rest and nutrition.
- Occasional mild abdominal discomfort — keep track of frequency and intensity, and consult a doctor if it worsens.
CCDC115-CDG — Frequently Asked Questions
Is this condition hereditary?
CCDC115-CDG is inherited in an autosomal recessive pattern, meaning both copies of the gene in each cell have mutations. Parents of an individual with autosomal recessive condition each carry one copy of the mutated gene but typically do not show signs and symptoms of the condition. The probability of passing the condition to children is 25% if both parents are carriers. De novo mutations are not common for this condition. Genetic counseling is recommended for affected families to understand risks and carrier status.
What is the life expectancy for someone with this condition?
Life expectancy can vary significantly depending on the severity and age of onset. Early diagnosis and management of symptoms can improve outcomes. Liver disease and other systemic complications are common causes of mortality. Treatment can help manage symptoms and potentially extend survival, but it is not curative. Realistic expectations should include a focus on quality of life and supportive care.
How is this condition diagnosed and how long does diagnosis take?
Diagnosis typically involves genetic testing, liver function tests, and glycomics analysis. The time from first symptoms to diagnosis can vary, often taking months to years due to the rarity and complexity of the condition. Specialists such as geneticists, hepatologists, and metabolic specialists are usually involved. Delayed diagnosis is often due to the nonspecific nature of early symptoms. Confirmation is achieved through genetic testing identifying mutations in the CCDC115 gene.
Are there any new treatments or clinical trials available?
Research is ongoing, with some promising studies focusing on gene therapy and enzyme replacement. Novel approaches like small molecule therapies are also being explored. ClinicalTrials.gov is a resource for finding current trials, and patients should discuss eligibility with their doctor. Questions to ask include potential benefits, risks, and the trial's phase. New treatments may take years to become widely available, but participation in trials can provide early access.
How does this condition affect daily life and activities?
Mobility and self-care may be impacted by fatigue and liver-related symptoms. Educational accommodations may be necessary due to cognitive or physical limitations. Social and emotional challenges include coping with chronic illness and potential isolation. Family burden can be significant, requiring support and resources. Adaptations such as physical therapy and counseling can greatly assist in managing daily life.
Support & Resources
References
Content generated with support from peer-reviewed literature via PubMed.
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Girard M, Poujois A, Fabre M et al. · Mol Genet Metab · 2018 · PMID: 29759592
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Geerts CJ, Alvarez F, Gilfix BM et al. · Mol Genet Metab · 2025 · PMID: 41037859
- 3.Clinical glycomics for the diagnosis of congenital disorders of glycosylation.
Abu Bakar N, Lefeber DJ, van Scherpenzeel M · J Inherit Metab Dis · 2018 · PMID: 29497882
- 4.Liver involvement in congenital disorders of glycosylation (CDG). A systematic review of the literature.
Marques-da-Silva D, Dos Reis Ferreira V, Monticelli M et al. · J Inherit Metab Dis · 2017 · PMID: 28108845
- 5.Serum bikunin isoforms in congenital disorders of glycosylation and linkeropathies.
Haouari W, Dubail J, Lounis-Ouaras S et al. · J Inherit Metab Dis · 2020 · PMID: 32700771
- 6.Expanded characterization of glycosylation abnormalities and galactose therapy in a patient with CCDC115-CDG using semi-quantitative N-glycan analysis of total and fractionated plasma glycoproteins, in response to Geerts et al. [1].
Liu Y, Lam C, Poskanzer S et al. · Mol Genet Metab · 2026 · PMID: 41499939
This content is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.Last reviewed: 2026-05-02