Congenital iodine deficiency syndrome degree of iodine deficiency was milder and manifested primarily as thyroid enlargement rather than severe mental and physical impairment. In Switzerland, for example, where soil does not contain a large amount of iodine, cases of congenital iodine deficiency syndrome were very abundant and even considered genetically caused. As the variety of food sources dramatically increased in Europe and North America and the populations became less completely dependent on locally grown food, the prevalence of endemic goitre diminished. The early 20th century saw the discovery of the relationships of neurological impairment with hypothyroidism due to iodine deficiency. Both have been largely
Complement deficiency Complement deficiency Complement deficiency is an immunodeficiency of absent or suboptimal functioning of one of the complement system proteins. Because there are redundancies in the immune system, many complement disorders are never diagnosed, some studies estimated that less than 10% are identified. "Hypocomplementemia" may be used more generally to refer to decreased complement levels while "secondary complement disorder" means decreased complement levels that are not directly due to a genetic cause but secondary to another medical condition. The following symptoms (signs) are consistent with complement deficiency in general: Vaccinations for encapsulated organisms (e.g., "Neisseria meningitidis" and "Streptococcus pneumoniae") is crucial