Kernicterus is a disorder where excess bilirubin accumulates in the deep neural tissues of the brain and can cause brain damage in the newborn.

It is characterized by jaundice and a limpness of the newborn, devoid of energy. Can present with seizures, convulsions, and muscle spasms.

This condition is treatable and requires awareness from the parents if yellowness of the skin (jaundice) is detected along with the above-mentioned signs in the early days post-partum. There are other signs not mentioned in this article

The word [kernicterus] comes from the German word [kern], meaning “nucleus” or “core”. In this particular word the term kern refers to the fact that one of the most importantly affected brain structures in kernicterus are the basal ganglia of the brain (also known as the "central nuclei", found at the "core" of the brain. It also includes the word [icterus] from the Greek word [ικτερός] pronounced (ikterós). The word [icterus] in Greek was originally used to denote a yellow bird, and is now used to denote the yellow color of jaundice.

 
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Sources:
1. Clayman, L. "The AMA Encyclopedia of Medicine" 1989. Random House, NY
2. “The Origin of Medical Terms” Skinner HA 1970 Hafner Publishing Co.

Thanks to Jackie Miranda-Klein for her contribution suggesting this word.