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Multiple sclerosis
MS causes the immune system to mistakenly attack the protective covering of nerve fibres, disrupting communication between the brain and the rest of the body. It typically affects adults and can lead to problems with movement, vision, and sensation.
Overview
Multiple Sclerosis (MS) is a long-term condition where the body's immune system attacks its own central nervous system, which includes the brain and spinal cord. This attack damages the myelin sheath, a fatty layer that insulates nerve fibres and helps messages travel quickly. When myelin is damaged, nerve signals can be slowed, distorted, or completely blocked, leading to various symptoms [PMID:33671217]. MS is considered a polygenic or complex condition, meaning it is influenced by multiple genetic factors as well as environmental factors.
Approximately 1 in 1,000 people in the UK are affected by MS. While it can develop at any age, symptoms typically begin between the ages of 20 and 40, and it is more common in women than men. The progression and severity of MS vary greatly among individuals, making it a highly individualised condition.
Symptoms & clinical features
The symptoms of Multiple Sclerosis can be very diverse, depending on which parts of the central nervous system are affected. Common initial symptoms often include fatigue, numbness or tingling sensations, muscle weakness, and problems with vision such as blurred vision or double vision. These symptoms may appear and disappear, or they might persist and worsen over time.
As the condition progresses, individuals may experience difficulties with balance and coordination, muscle spasms, issues with bladder and bowel control, and cognitive changes like problems with memory or concentration. Mood changes, such as depression or anxiety, are also commonly reported. The unpredictable nature of MS symptoms can significantly impact daily life.
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Affected organs
Multiple Sclerosis primarily affects the central nervous system, which comprises the brain and spinal cord. The immune system's attack targets the myelin sheath surrounding nerve fibres within these organs. This damage leads to lesions or 'plaques' in various areas, disrupting the normal flow of electrical signals.
The eyes are also commonly affected, particularly the optic nerves, which can lead to visual disturbances. Although MS is a neurological condition, its widespread impact on nerve pathways can indirectly affect many body functions controlled by the central nervous system, such as muscle movement, sensation, and organ control.
Risks & severity
The severity of Multiple Sclerosis varies considerably between individuals, ranging from mild symptoms that cause little disability to more severe forms that can lead to significant physical impairment. Most people with MS experience periods of new or worsening symptoms (relapses) followed by periods of recovery (remission), known as relapsing-remitting MS. Over time, some individuals may transition to a progressive form where symptoms steadily worsen [PMID:34524458]. A smaller proportion of people experience primary progressive MS, where symptoms gradually worsen from the outset.
The exact lifetime risk of developing MS for a person in the general population is approximately 1 in 1,000, though this can be higher for individuals with a family history of the condition. Environmental factors, such as vitamin D deficiency, smoking, and certain viral infections, are also thought to increase risk. While MS is a chronic condition, treatments can help manage symptoms, reduce the frequency of relapses, and slow disease progression for many individuals.
Genetic causes
Multiple Sclerosis is considered a polygenic condition, meaning that changes in multiple genes, in combination with environmental factors, contribute to an individual's risk. There isn't a single 'MS gene', but rather several genes that may increase susceptibility. These genes often play roles in the immune system.
Two genes, IL2RA and IL7R, are examples of genes that research suggests may be associated with an increased risk of MS [PMID:22080327]. The IL2RA gene provides instructions for a component of the interleukin-2 receptor, which is important for regulating immune cell activity. Similarly, the IL7R gene gives instructions for the interleukin-7 receptor alpha chain, a protein found on immune cells that is crucial for their development and proliferation. Variants in these genes might alter immune responses, potentially contributing to the autoimmune attack seen in MS. However, having variants in these genes does not mean an individual will definitely develop MS.
Inheritance pattern
Multiple Sclerosis follows a polygenic or complex inheritance pattern. This means it is not inherited in a simple dominant or recessive way. Instead, the condition arises from a combination of changes in multiple genes and various environmental factors.
While MS can sometimes appear in more than one family member, it is generally not considered directly hereditary in the same way as single-gene disorders. Having a close relative with MS, such as a parent or sibling, can slightly increase an individual's risk compared to the general population, but most people with MS do not have an affected parent. This complex inheritance pattern makes it difficult to predict who will develop the condition based solely on family history.
Diagnosis & testing
Diagnosing Multiple Sclerosis typically involves a combination of clinical assessment, neurological examination, and imaging studies. A neurologist will evaluate a person's symptoms and medical history. Magnetic Resonance Imaging (MRI) scans of the brain and spinal cord are crucial, as they can reveal the characteristic lesions (damaged areas) associated with MS [PMID:33671217].
Other diagnostic tests may include a lumbar puncture (spinal tap) to examine cerebrospinal fluid for specific markers, and evoked potential tests, which measure the electrical activity of the brain in response to sensory stimulation. Genetic testing for specific genes like IL2RA or IL7R is generally not used for diagnosing MS in a clinical setting because the condition is polygenic; instead, genetic research aims to understand susceptibility. In the UK, if MS is suspected, a GP would typically refer a patient to a neurologist for further assessment and diagnosis. This pathway aligns with the NHS Genomic Medicine Service where genetic testing for polygenic conditions may be discussed in a research context, but not usually for routine diagnosis.
Management & lifestyle
Managing Multiple Sclerosis focuses on treating relapses, slowing the progression of the disease, and alleviating symptoms. Disease-modifying therapies (DMTs) are available that can reduce the frequency and severity of relapses and may slow the accumulation of disability for some people [PMID:34524458]. These treatments are typically prescribed and monitored by a neurologist.
Symptomatic management involves a multidisciplinary approach, often including physiotherapists, occupational therapists, speech and language therapists, and pain management specialists. Lifestyle considerations, such as regular exercise, a balanced diet, and avoiding smoking, may also play a role in overall well-being. Individuals with MS in the UK can access care through the NHS, with specialist MS nurses and neurologists providing ongoing support and treatment planning. Genetic counsellors can provide information on the complex genetic risks to family members, but they do not manage the medical treatment of MS.
UK care pathway
In the UK, if Multiple Sclerosis is suspected, the initial step is typically a referral from a General Practitioner (GP) to a neurologist. The neurologist will conduct a comprehensive assessment, including clinical examination and diagnostic tests like MRI scans and potentially a lumbar puncture. While genetic research into MS susceptibility genes (e.g., IL2RA, IL7R) is ongoing, routine genetic testing for diagnosis is not part of the standard NHS care pathway for MS, which is a complex, polygenic condition. Genomic testing for polygenic conditions is usually within a research context rather than clinical diagnosis, so specific NHS R-codes are not typically applied for diagnostic genetic testing for MS. Clinical genetics services and genetic counsellors can offer support for families concerned about genetic risk and inheritance patterns, particularly in understanding the complex nature of polygenic conditions.
Frequently asked questions
Is Multiple Sclerosis always progressive?
No, not always. The most common form is relapsing-remitting MS, where symptoms come and go. Some people may eventually transition to a progressive form, or a smaller number might have progressive MS from the start. The progression varies significantly among individuals.
Can my children inherit MS?
MS is not inherited in a simple way like some genetic conditions. It's a complex condition influenced by many genes and environmental factors. Having a close relative with MS slightly increases risk, but most people with MS do not pass it on directly, and most children of people with MS will not develop the condition.
What causes the immune system to attack itself in MS?
The exact reason why the immune system mistakenly attacks the central nervous system in MS is not fully understood. It is thought to be a combination of genetic predispositions and environmental factors, such as certain viral infections, vitamin D deficiency, and smoking, that trigger this autoimmune response.
Are there different types of MS?
Yes, there are several types of MS. The most common is relapsing-remitting MS (RRMS), characterised by periods of symptoms (relapses) followed by recovery (remission). Other forms include secondary progressive MS (SPMS), where RRMS transitions to a steady worsening of symptoms, and primary progressive MS (PPMS), where symptoms gradually worsen from the outset without distinct relapses or remissions.
Can lifestyle changes help manage MS?
While lifestyle changes cannot cure MS, maintaining a healthy lifestyle is often recommended as part of a comprehensive management plan. This may include regular exercise, a balanced diet, avoiding smoking, and managing stress. These factors can contribute to overall well-being and potentially help with symptom management, but they do not replace medical treatments.
References
- Carlson AK, Fox RJ. Pathophysiology, Diagnosis, Treatment and Emerging Neurotherapeutic Targets for Progressive Multiple Sclerosis: The Age of PIRA. Neurologic clinics. 2024. PMID: 37980122
- Titcomb TJ, Giesser BS, Plafker SM. Editorial: Diet and multiple sclerosis. Frontiers in neurology. 2023. PMID: 38152642
- Giovannoni G, Hawkes CH, Lechner-Scott J. When does multiple sclerosis start? Multiple sclerosis and related disorders. 2025. PMID: 40947157
- Dobson R, Tanasescu R, Gran B. Editorial: Preventing multiple sclerosis. Frontiers in neurology. 2022. PMID: 35937063
- Hawkes CH, Giovannoni G, Lechner-Scott J. Migraine and multiple sclerosis: The final answer? Multiple sclerosis and related disorders. 2023. PMID: 37270888
- Alghanimy AA, Giovannoni G, Lechner-Scott J. Is multiple sclerosis a glymphaticopathy? Multiple sclerosis and related disorders. 2023. PMID: 38039696
- Ontaneda D, Miron VE. Breaking Barriers in Multiple Sclerosis. Multiple sclerosis (Houndmills, Basingstoke, England). 2024. PMID: 39658898
- SCHUMACHER GA. Multiple sclerosis. The American journal of nursing. 1957. PMID: 13424570