It is also associated with Crigler–Najjar syndrome, a more serious disorder where the enzymes activity is either completely absent (Crigler–Najjar syndrome type I) or less than 10% of normal (type II). Infants may have a developmental deficiency in UDP-glucuronyl transferase, and are unable to hepatically metabolize the antibiotic drug chloramphenicol which requires glucuronidation. This leads to a condition known as gray baby syndrome. Causes
Causes of unconjugated hyperbilirubinemia are divided into three main categories, namely, excessive bilirubin synthesis, liver bilirubin uptake malfunction, and bilirubin conjugation compromise.As to excessive bilirubin synthesis, both intravascular hemolysis and extravascular hemolysis can involve in the pathophysiology. Additionally, dyserythropoiesis and extravasation of blood into tissues such as angioedema and edema can also lead to indirect hyperbilirubinemia, along with heart failure, medication-induced, ethinyl estradiol, chronic hepatitis, and cirrhosis that are, otherwise, attributed to hepatic bilirubin mal-uptake and bilirubin conjugation compromise, respectively. Genes
Human genes which encode UGT enzymes include:

B3GAT1, B3GAT2, B3GAT3
UGT1A1, UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10
UGT2A1, UGT2A2, UGT2A3, UGT2B4, UGT2B7, UGT2B10, UGT2B11, UGT2B15, UGT2B17, UGT2B28

References
External links
Glucuronosyltransferase at the US National Library of Medicine Medical Subject Headings (MeSH)
Treatments
Procedures
Hydrocephalus treatment is surgical, creating a way for the excess fluid to drain away. In the short term, an external ventricular drain (EVD), also known as an extraventricular drain or ventriculostomy, provides relief. In the long term, some people will need any of various types of cerebral shunt. It involves the placement of a ventricular catheter (a tube made of silastic) into the cerebral ventricles to bypass the flow obstruction/malfunctioning arachnoidal granulations and drain the excess fluid into other body cavities, from where it can be resorbed. Most shunts drain the fluid into the peritoneal cavity (ventriculoperitoneal shunt), but alternative sites include the right atrium (ventriculoatrial shunt), pleural cavity (ventriculopleural shunt), and gallbladder. A shunt system can also be placed in the lumbar space of the spine and have the CSF redirected to the peritoneal cavity (lumbar-peritoneal shunt). An alternative treatment for obstructive hydrocephalus in selected people is the endoscopic third ventriculostomy (ETV), whereby a surgically created opening in the floor of the third ventricle allows the CSF to flow directly to the basal cisterns, thereby shortcutting any obstruction, as in aqueductal stenosis. This may or may not be appropriate based on individual anatomy. For infants, ETV is sometimes combined with choroid plexus cauterization, which reduces the amount of cerebrospinal fluid produced by the brain. The technique, known as ETV/CPC, was pioneered in Uganda by neurosurgeon Benjamin Warf and is now in use in several U.S. hospitals. Hydrocephalus can be successfully treated by placing a drainage tube (shunt) between the brain ventricles and abdominal cavity.