Waardenburg syndrome (WS) is named after the Dutch ophthalmologist Petrus Johannes Waardenburg, who, in 1947, first described a patient with hearing loss, dystopia canthorum (ie, lateral displacement of the inner canthi of the eyes), and retinal pigmentary differences.
Vitamin A Deficiency-Related Disorders (VADD). The most damaging micronutrient deficiencies in the world are the consequence of low dietary intake of iron, vitamin A, iodine and zinc.Vitamin A deficiency (VAD) is prevalent among the poor whose diets are based mainly on rice or other carbohydrate-rich, micronutrient-poor calory sources.itamin A Deficiency-Related Disorders (VADD). The most damaging micronutrient deficiencies in the world are the consequence of low dietary intake of iron, vitamin A, iodine and zinc.
Micronutrients play a central part in metabolism and in the maintenance of tissue function. An adequate intake therefore is necessary, but provision of excess supplements to people who do not need them may be harmful. Single micronutrient deficiency states are comparatively easily recognised and treated.