NON RARE IN EUROPE: Multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). It is characterized by the immune-mediated destruction of myelin sheaths that insulate nerve fibers in the brain, spinal cord, and optic nerves, leading to disrupted signal transmission between the brain and the rest of the body. MS is one of the most common neurological disorders affecting young adults and is classified as non-rare in Europe due to its relatively high prevalence in that region. The disease presents in several clinical forms, including relapsing-remitting MS (RRMS), which is the most common initial presentation and features episodes of neurological dysfunction followed by partial or complete recovery; secondary progressive MS (SPMS), which develops from RRMS with gradual worsening; and primary progressive MS (PPMS), characterized by steady neurological decline from onset. Key symptoms include visual disturbances (such as optic neuritis), fatigue, muscle weakness, spasticity, sensory disturbances (numbness, tingling, pain), balance and coordination problems (ataxia), bladder and bowel dysfunction, cognitive impairment, and depression. Symptoms vary widely between individuals depending on the location and extent of CNS lesions. The exact cause of MS remains incompletely understood, but it is considered a multifactorial disease involving both genetic susceptibility and environmental factors. The strongest genetic association is with the HLA-DRB1*15:01 allele in the major histocompatibility complex region, and over 200 additional genetic risk variants have been identified. Environmental risk factors include low vitamin D levels, Epstein-Barr virus infection, smoking, and obesity during adolescence. Treatment has advanced significantly, with numerous disease-modifying therapies (DMTs) now available, including interferons, glatiramer acetate, natalizumab, fingolimod, ocrelizumab, cladribine, and others. These therapies aim to reduce relapse frequency, slow disability progression, and limit new CNS lesion formation. Symptomatic treatments are also used to manage fatigue, spasticity, pain, and other manifestations. While there is currently no cure for MS, early diagnosis and treatment initiation are associated with better long-term outcomes.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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