Cohen syndrome is a rare, hereditary genetic disorder characterized by a set of clinical and physical symptoms.
What is Cohen syndrome?
Cohen syndrome, (referring to the doctor who first described it in 1973), is a rare and hereditary genetic disease. “It is inherited in an autosomal recessive manner, meaning that for a person to have Cohen syndrome, they must inherit two mutated copies of the causative gene, one from each parent“, explains Laurence Duplomb-Jego, researcher in cell biology.
What are the symptoms of Cohen syndrome?
The characteristics of Cohen syndrome are fairly homogeneous but may vary from person to person. This may be :
- Developmental delay, both on a motor and cognitive level. Walking, for example, can be acquired late, around the age of 4. Some patients will have access to language and others will not
- Autistic traits can also be associated.
- Facial dysmorphism: Distinctive facial features associated with Cohen syndrome may include a prominent nasal bridge with a short philtrum, thick, low-growing hair, a grimacing smile.
- Eye problems very young people with rapid retinal degeneration, which can lead to progressive loss of vision. “Many patients have cataracts early compared to the general population.
- Blood abnormalities: neutropenia (i.e. too low a quantity of neutrophils in the blood) is characteristic of Cohen’s syndrome, however children do not develop more infections, of the ENT type for example, than other children of the same child. age.
- Abnormal distribution of fats, with accumulation belly fat, the limbs remain thin. The fingers are particularly very slender.
- Glucose intolerance, which puts them at risk of developing type 2 diabetes. 70% of them have HDL (good cholesterol) levels that are too low, which puts them at risk of developing cardiovascular diseases.
- Renal abnormalities
- Gastrointestinal problems
- Lipid metabolism disorders…
What causes Cohen syndrome?
Cohen syndrome is caused by mutations in a specific gene called VPS13B (Vacuolar Protein Sorting 13 Homolog B). This gene is located on chromosome 8. “VPS13B encodes a protein that plays a role in maintaining the integrity of an important structure in the cell called the apparatus of Golgithis is important in the proper constitution of proteins and in the intracellular transport of proteins“, explains the specialist. These mutations cause a dysfunction in different cells of the body which leads to the symptoms of patients. As it is a genetic disease said “autosomal recessive“, an individual must inherit two mutated copies of the gene (one from each parent) to develop the syndrome.
Typical facial features are rarely identifiable in babies and toddlers
“The diagnosis of Cohen syndrome is based on several elements collected during a complete clinical evaluation carried out by a specialist doctor or geneticist.underlines our interlocutor.
► The doctor collects patient history, examines symptoms and performs a physical examination. Thus, a combination of clinical symptoms such as microcephaly (small head circumference), hypotonia, abnormal fat distribution, vision problems and neutropenia can point towards a diagnosis of Cohen syndrome. The typical facial characteristics of Cohen syndrome will only help with the diagnosis in children aged 5 or 6 years old., because they appear during development and are rarely identifiable in babies and toddlers. Because many patients with Cohen syndrome have vision problems, a complete eye exam is usually performed. “This includes an examination of the retina to detect retinal pigmentation, edema and degeneration.”
► A genetic analysis is essential to confirm the presence of mutations in VPS13B and conclude the diagnosis of Cohen syndrome. “Today, it is generally an exome that is prescribed and which allows all of the patient’s genes to be sequenced. The specific mutations in VPS13B are then identified and allow the diagnosis to be definitively made.“, she continues.
► Medical imaging exams (x-rays or ultrasounds) can be used to assess other aspects of the patient’s health, including internal organs and bones.
► Certain blood tests are performed regularly to assess organ function, such as liver. “These blood tests make it possible to check various metabolic parameters such as glucose intolerance and the risk of diabetes, cholesterol (HDL, LDL) linked to obesity. Hematological monitoring must be regular to control neutropenia.
► Development evaluationincluding cognitive tests and assessments of motor development, may be performed to assess potential delays in children with Cohen syndrome (schooling is often done in EMI)
What is the life expectancy for Cohen syndrome?
In many cases, people with Cohen syndrome have normal life expectancy. However, some serious medical complications, such as heart problems Or complications linked to obesity, can affect the lifespan. “It is a rare pathology, with moderate to severe clinical consequences.recalls Laurence Duplomb-Jego. Specialized medical care, rehabilitation, regular medical monitoring and management of specific symptoms help to improve quality of life and prevent or treat potential medical complications.”.
Once the diagnosis is confirmed, a team of health professionals (speech therapists, psychomotor therapists, etc.) can work with the patient to develop a personalized care plan which addresses the patient’s specific symptoms and medical needs. Regular medical monitoring by specialized health professionals. is often necessary to monitor the progression of the disease and adapt treatments accordingly. There is no curative treatment. “However, management focuses on managing specific symptoms (such as specific treatments for retinal damage), preventing medical complications, and improving the patient’s quality of life.“, explains the specialist.
► Glasses and visual rehabilitation can alleviate vision problems, such as retinal degeneration. Cataract can be operated on.
► Re-educationincluding physical therapy, occupational therapy, and speech therapy, may be beneficial for people with Cohen syndrome, particularly in improving motor coordination and motor development.
► Psychological and social support is important in helping people with Cohen syndrome and their families cope with the challenges associated with the disease. Support groups and counseling services can be helpful. There are national and international associations (http://www.cohensyndrome.org/) to connect families affected by this symptom.
Thanks to Laurence Duplomb-Jego, researcher at Dijon University Hospital, in the GAD (Genetics of Developmental Anomalies) team led by Professor Christel Thauvin, UMR Inserm 1231. Patients are seen in consultation by Professor Laurence Faivre, referent of Cohen syndrome, and head of the Genetics center at Dijon University Hospital.