出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/03/27 13:39:39」(JST)
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Crigler–Najjar syndrome | |
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Classification and external resources | |
Bilirubin |
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ICD-10 | E80.5 |
ICD-9 | 277.4 |
OMIM | 218800 606785 |
DiseasesDB | 3176 |
MedlinePlus | 001127 |
eMedicine | med/476 |
MeSH | D003414 |
Crigler–Najjar syndrome or CNS is a rare disorder affecting the metabolism of bilirubin, a chemical formed from the breakdown of red blood cells. The disorder results in an inherited form of non-hemolytic jaundice, which results in high levels of unconjugated bilirubin and often leads to brain damage in infants.
This syndrome is divided into type I and type II, with the latter sometimes called Arias syndrome. These two types, along with Gilbert's syndrome, Dubin–Johnson syndrome, and Rotor syndrome, make up the five known hereditary defects in bilirubin metabolism. Unlike Gilbert's syndrome, only a few hundred cases of CNS are known.
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This is a very rare disease (estimated at 0.6–1.0 per million live births), and consanguinity increases the risk of this condition (other rare diseases may be present). Inheritance is autosomal recessive.
Intense jaundice appears in the first days of life and persists thereafter. Type 1 is characterised by a serum bilirubin usually above 345 µmol/L (310–755) (whereas the reference range for total bilirubin is 2–14 μmol/L).
No UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1) expression can be detected in the hepatic tissue. Hence, there is no response to treatment with phenobarbital[1] (which causes CYP450 enzyme induction). Most patients (type IA) have a mutation in one of the common exons (2 to 5), and have difficulties conjugating several additional substrates (several drugs and xenobiotics). A smaller percentage of patients (type IB) have mutations limited to the bilirubin-specific A1 exon; their conjugation defect is mostly restricted to bilirubin itself.
Before the availability of phototherapy, these children died of kernicterus (bilirubin encephalopathy) or survived until early adulthood with clear neurological impairment. Today, therapy includes
Type II differs from type I in several aspects:
Neonatal jaundice may develop in the presence of sepsis, hypoxia, hypoglycemia, hypothyroidism, hypertrophic pyloric stenosis, galactosemia, fructosemia, and so on.
Hyperbilirubinemia of the unconjugated type may be caused by
In Crigler–Najjar syndrome and Gilbert syndrome, routine liver function tests are normal, and hepatic histology usually is, too. There is no evidence for hemolysis. Drug-induced case typically regress after discontinuation of the substance. Physiological neonatal jaundice may peak at 85–170 µmol/L and decline to normal adult concentrations within two weeks. Prematurity results in higher levels.
One 10-year-old girl with Crigler–Najjar syndrome type I was successfully treated by hepatocyte transplantation.[3]
The homozygous Gunn rat, which lacks the enzyme uridine diphosphate glucuronyltransferase (UDPGT), is an animal model for the study of Crigler–Najjar syndrome. Since there is only one enzyme working improperly, gene therapy for Crigler Najjar is a theoretical option which is being investigated.[4]
The condition is named for John Fielding Crigler (b. 1919), an American Pediatrician and Victor Assad Najjar (b. 1914), a Lebanese-American Pediatrician.[5][6]
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リンク元 | 「クリグラー・ナジャー症候群」 |
関連記事 | 「syndrome」 |
体質性黄疸 | 遺伝形式* | ビリルビン型 | ビリルビン値 | 予後 |
Crigler-Najjar症候群I型 | 常染色体劣性 | 間接型(非抱合) | 21-31mg/dl | 致死的 |
Crigler-Najjar症候群II型 | 常染色体劣性 | 8-18mg/dl | 良好 | |
Gilbert症候群 | 常染色体優性 | <6mg/dl | きわめて良好 | |
Dubin-Johnson症候群 | 常染色体劣性 | 直接型(抱合) | 2-5(-25)mg/dl | きわめて良好 |
Rotor症候群 | 常染色体劣性 | 2-5(-20)mg/dl | きわめて良好 | |
*劣性か優性かについては例外あり |
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