Editing Bilirubin (section)

==== Kernicterus ====
{{main|Kernicterus}}
Unbound bilirubin (Bf) levels can be used to predict the risk of  neurodevelopmental handicaps within infants.<ref name="SciFinder">{{cite journal|last1=Hegyi|first1=T.|last2=Chefitz|first2=D.|last3=Weller|first3=A.|last4=Huber|first4=A|last5=Carayannopoulos|first5=M.|last6=Kleinfeld|first6=A.|date=2020|title=Unbound bilirubin measurements in term and late-preterm infants|journal=Journal of Maternal-Fetal & Neonatal Medicine|volume=35 |issue=8 |pages=1532–1538|doi=10.1080/14767058.2020.1761318|pmid=32366186|pmc=7609464}}</ref> Unconjugated [[Hyperbilirubinaemia|hyperbilirubinemia]] in a newborn can lead to accumulation of bilirubin in certain brain regions (particularly the [[basal nuclei]]) with consequent irreversible damage to these areas manifesting as various neurological deficits, [[seizure]]s, abnormal [[reflexes]] and eye movements. This type of neurological injury is known as kernicterus. The spectrum of clinical effect is called [[bilirubin encephalopathy]]. The neurotoxicity of neonatal hyperbilirubinemia manifests because the [[blood–brain barrier]] has yet to develop fully,{{Dubious|Toxicity_.26_the_blood-brain_barrier|date=September 2014}} and bilirubin can freely pass into the brain interstitium, whereas more developed individuals with increased bilirubin in the blood are protected. Aside from specific chronic medical conditions that may lead to hyperbilirubinemia, neonates in general are at increased risk since they lack the intestinal bacteria that facilitate the breakdown and excretion of conjugated bilirubin in the feces (this is largely why the feces of a neonate are paler than those of an adult). Instead the conjugated bilirubin is converted back into the unconjugated form by the enzyme [[Beta-glucuronidase|β-glucuronidase]] (in the gut, this enzyme is located in the brush border of the lining intestinal cells) and a large proportion is reabsorbed through the [[enterohepatic circulation]]. In addition, recent studies point towards high total bilirubin levels  as a cause for gallstones regardless of gender or age.<ref>{{cite journal|last1=Zeng|first1=D.|last2=Wu|first2=H.|last3=Huang|first3=Q.|last4=Zeng|first4=A.|last5=Yu|first5=Z.|last6=Zhong|first6=Z.|date=2021|title=High levels of serum triglyceride, low-density lipoprotein cholesterol, total bile acid, and total bilirubin are risk factors for gallstones|url=https://pubmed.ncbi.nlm.nih.gov/34383399/|journal=Clinical Laboratory|volume=67|issue=8|pages=1905–1913|doi=10.7754/Clin.Lab.2021.201228|pmid=34383399|s2cid=234775572|access-date=November 11, 2021|via=PubMed}}</ref>