Country of birth among pediatric-onset MS patients and their parents. Patients (n = 27) and parents (n = 102) with missing birth country data are excluded. Countries are categorized as follows: Central and South America: Argentina, Brazil, Chile, Colombia, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Mexico, Nicaragua, Panama, Peru, Suriname, and Venezuela; Caribbean: Antigua, Bahamas, Barbados, Dominican Republic, Grenada, Haiti, Jamaica, Puerto Rico, Virgin Islands, and West Indies; Asia: Afghanistan, China, Hong Kong, India, Pakistan, Philippines, South Korea, Taiwan, Vietnam, and Asia otherwise unknown; Europe: Albania, Bosnia, England, United Kingdom, Germany, Italy, Netherlands, Portugal, Russia, and Serbia; Middle East: Iran, Israel, Jordan, Saudi Arabia, United Arab Emirates, and Yemen; North America other: Bermuda and Canada; Other (Africa, Oceania): Cape Verde, Egypt, Fiji, Liberia, Libya, Nigeria, Tunisia, and Outside the United States otherwise unknown.