TMEM165-CDG, or TMEM165 glycosyltransferase dysfunction, is a rare genetic disorder belonging to the group of glycosylation diseases (CDG). This disease is associated with a defect in the synthesis of carbohydrates and their precursors, leading to the accumulation of unidentified uncomplicated oligomers and useless glycoproteins in cells. TMEM165-CDG is an autosomal recessive disease and is characterized by multiple clinical manifestations, including neurological and rare systemic disorders. These disorders can range from mild to severe, and their symptoms can include growth failure, cardiovascular pathologies, as well as liver and kidney pathologies.
History of the disease and interesting historical facts
TMEM165-CDG was initially described in 2014, when a group of researchers identified mutations in the TMEM165 gene in several patients exhibiting symptoms typical of glycosyltransferase syndromes. In this context, an important development was the creation of an international network of researchers and specialists working on this pathology, which allowed for the collection of more data on various aspects of the disease. One of the significant achievements was the establishment of a correlation between the types of mutations in the gene and the clinical manifestations of the disease. Thus, some mutations led to more severe manifestations than others, which made it possible to identify potential predictors of the course of the disease and its outcome.
Epidemiology
TMEM165-CDG is an extremely rare disease, making it difficult to estimate its prevalence and risk factors. The incidence rate is reported to be approximately 1 in 1,000,000 live births, but this number may vary depending on the population structure. Higher rates are observed in populations with a higher inbreeding load, where cases of TMEM165-CDG are more common. As of 2023, only a few dozen cases of the disease have been reported in the scientific literature, confirming its rarity.
Genetic predisposition to this disease
TMEM165-CDG is caused by mutations in the TMEM165 gene located on chromosome 2. In most cases, the disease is inherited in an autosomal recessive manner, meaning that two mutant alleles are required to cause clinical symptoms. Given the high level of homozygosity in some populations, key mutations have been identified, such as deletions and nucleotide substitutions, which result in complete loss of gene function. Such mutations have a major impact on glycoprotein biosynthesis and, as a consequence, cause clinical manifestations of the disease.
Risk factors for the development of this disease
Risk factors for TMEM165-CDG are mainly related to genetic predisposition, as the disease is inherited in an autosomal recessive manner. Complications may occur if the following conditions are present:
- Family history of the disease – cases of TMEM165-CDG are more often observed in close relatives, indicating inbreeding.
- Genetic predisposition – the presence of a known mutation in the TMEM165 gene in one of the parents significantly increases the risk of the disease in the offspring.
- Gender factors – although the disease is not gender specific, some epidemiological studies show slight differences in manifestations between men and women.
Diagnosis of this disease
Diagnosis of TMEM165-CDG requires a comprehensive approach, including identification of clinical symptoms and the use of laboratory tests. The main symptoms of the disease include:
- Delayed development and growth.
- Neurological disorders including psychomotor retardation.
- Problems with the cardiovascular system and liver.
Laboratory tests often include:
- Checking the level of glycosylated proteins in the blood serum.
- Genetic testing to detect mutations in the TMEM165 gene.
Radiological examinations such as abdominal ultrasound may be used to evaluate the liver and spleen. Differential diagnosis should include other glycosylated diseases and metabolic disorders.
Treatment
There is currently no specific treatment for TMEM165-CDG, and therapy is primarily aimed at relieving symptoms and maintaining the patient's general condition. Common treatment approaches include:
- Clinical monitoring of growth and development of children.
- Pharmacological therapy for the correction of metabolic disorders.
- Symptomatic treatment aimed at correcting cardiovascular and liver disorders.
- In some cases, surgery may be required to correct anatomical abnormalities.
List of medications used to treat this disease
The list of drugs used to treat TMEM165-CDG may vary depending on the clinical manifestations, but often includes:
- Enzyme replacement therapy.
- Medicines that improve metabolism and liver function.
- Drugs for the correction of cardiovascular disorders.
Disease monitoring
Monitoring of the patient's condition with TMEM165-CDG includes:
- Regular medical check-ups to assess growth and development.
- Laboratory tests to monitor the level of glycosylated proteins.
- Evaluation of the effectiveness of the treatment and possible side effects.
The prognosis for patients with TMEM165-CDG may vary depending on the severity of the disease and the timing of interventions. Complications may include more complex forms of cardiovascular and neurological impairment, which require professional monitoring.
Age-related features of the disease
TMEM165-CDG can manifest at different ages, and its course may differ depending on the patient group:
- In infants, the disease can manifest itself in the first months of life through delayed growth and development.
- In older children, clinical manifestations may include neurological disorders and chronic liver disease.
- In adults, the risk of developing complications such as cardiovascular disease increases significantly.
Questions and Answers
- What is TMEM165-CDG? It is a rare genetic disorder associated with impaired carbohydrate synthesis due to mutations in the TMEM165 gene.
- What are the main symptoms of the disease? This may include growth retardation, neurological disorders, and liver problems.
- How is TMEM165-CDG diagnosed? Diagnosis includes clinical examination, genetic testing, and laboratory tests for glycosylated protein levels.
- What are the current approaches to treating TMEM165-CDG? Treatment is symptomatic, aimed at correcting metabolic disorders and managing complications.
- What is the prognosis for patients with TMEM165-CDG? Prognosis varies depending on the severity of the disease and initial intervention, but some patients can lead relatively normal lives with adequate monitoring.
