Iodine in biology damage). In areas where there is little iodine in the diet, typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten, iodine deficiency also gives rise to hypothyroidism, the most serious symptoms of which are epidemic goitre (swelling of the thyroid gland), extreme fatigue, mental slowing, depression, weight gain, and low basal body temperatures. The addition of iodine to table salt (so-called iodized salt) has largely eliminated the most severe consequences of iodine deficiency in wealthier nations, but deficiency remains a serious public health problem in the developing world. Iodine deficiency is also a problem in
Isobutyryl-coenzyme A dehydrogenase deficiency Isobutyryl-coenzyme A dehydrogenase deficiency Isobutyryl-coenzyme A dehydrogenase deficiency, commonly known as IBD deficiency, is a rare metabolic disorder in which the body is unable to process certain amino acids properly. People with this disorder have inadequate levels of an enzyme that helps break down the amino acid valine, resulting in a buildup of valine in the urine, a symptom called valinuria. Defects in the "ACAD8" gene cause isobutyryl-coenzyme A dehydrogenase deficiency. The "ACAD8" gene provides instructions for making an enzyme that plays an essential role in breaking down proteins from the diet. Specifically, the enzyme is responsible for processing valine,