A rare autosomal recessive disorder of bilirubin metabolism caused by biallelic mutations in UGT1A1, the gene encoding the hepatic enzyme that glucuronidates bilirubin. Loss of that activity produces severe, non-haemolytic unconjugated hyperbilirubinaemia from the neonatal period. Two forms are distinguished by residual enzyme activity: type 1, with complete absence of UGT1A1 activity, severe jaundice, and a high risk of bilirubin-induced neurological dysfunction (kernicterus); and type 2, with partial activity, lower bilirubin levels, and little to no kernicterus risk. Crigler-Najjar syndrome sits at the severe end of the same UGT1A1 activity-loss spectrum whose mild end is Gilbert's syndrome. Type 1 requires lifelong intensive phototherapy as containment while liver transplantation remains the only definitive cure; type 2 typically responds to phenobarbital, which induces the residual enzyme.
Ask a research question about Crigler-Najjar Syndrome. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).
Do not include personal health information in your question. Questions and results are cached in your browser's local storage.
name: Crigler-Najjar Syndrome
creation_date: "2026-08-22T00:00:00Z"
category: Mendelian
description: >-
A rare autosomal recessive disorder of bilirubin metabolism caused by
biallelic mutations in UGT1A1, the gene encoding the hepatic enzyme that
glucuronidates bilirubin. Loss of that activity produces severe,
non-haemolytic unconjugated hyperbilirubinaemia from the neonatal period. Two
forms are distinguished by residual enzyme activity: type 1, with complete
absence of UGT1A1 activity, severe jaundice, and a high risk of
bilirubin-induced neurological dysfunction (kernicterus); and type 2, with
partial activity, lower bilirubin levels, and little to no kernicterus risk.
Crigler-Najjar syndrome sits at the severe end of the same UGT1A1
activity-loss spectrum whose mild end is Gilbert's syndrome. Type 1 requires
lifelong intensive phototherapy as containment while liver transplantation
remains the only definitive cure; type 2 typically responds to phenobarbital,
which induces the residual enzyme.
disease_term:
preferred_term: Crigler-Najjar syndrome
term:
id: MONDO:0009044
label: Crigler-Najjar syndrome
parents:
- Liver Disease
- Inherited Metabolic Disorder
has_subtypes:
- name: Type 1
display_name: Crigler-Najjar syndrome type 1 (complete UGT1A1 deficiency)
description: >-
The severe form, caused by UGT1A1 mutations abolishing enzyme activity
entirely. Severe unconjugated hyperbilirubinaemia appears in the neonatal
period and carries a high risk of kernicterus. Management requires
aggressive containment - prolonged daily phototherapy, exchange transfusion
or plasmapheresis for crises - and liver transplantation is the only
definitive cure. Phenobarbital does not work, because there is no residual
enzyme to induce.
subtype_term:
preferred_term: Crigler-Najjar syndrome type 1
term:
id: MONDO:0021020
label: Crigler-Najjar syndrome type 1
- name: Type 2
display_name: Crigler-Najjar syndrome type 2 (partial UGT1A1 deficiency, Arias syndrome)
description: >-
The milder form, caused by UGT1A1 mutations that leave residual enzyme
activity. Serum bilirubin is lower than in type 1 and the risk of
kernicterus is low. Patients respond well to phenobarbital, which induces
the residual enzyme, and most survive into adulthood without neurological
damage.
subtype_term:
preferred_term: Crigler-Najjar syndrome type 2
term:
id: MONDO:0011725
label: Crigler-Najjar syndrome type 2
prevalence:
- population: Worldwide newborns
measure_type: BIRTH_PREVALENCE
prevalence_class: BELOW_1_IN_1000000
rate_low: 0.06
rate_high: 0.1
notes: >-
Reported as approximately 0.6-1 per million newborns worldwide; expressed
here per 100,000 as 0.06-0.1. Higher in genetically isolated populations
(Old Order Amish and Mennonite communities) and among offspring of
consanguineous parents.
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
CNS is an extremely rare disorder, affecting approximately 0.6 to 1 in
every 1 million newborns worldwide and fewer than 1 in 100,000 individuals
in Europe
explanation: >-
Provides the birth-prevalence estimate recorded here. Evidence source is
OTHER because this is a scoping review of the published literature rather
than a primary epidemiological study.
pathophysiology:
- name: Complete or Severe Loss of UGT1A1 Glucuronidation Activity
description: >-
Biallelic mutations in UGT1A1, on chromosome 2q37, impair or abolish the
activity of bilirubin UDP-glucuronosyltransferase, the enzyme that
conjugates unconjugated bilirubin with glucuronic acid to make it
water-soluble and excretable in bile. The extent of activity loss sets the
disease type: complete absence gives type 1, partial retention gives type 2.
This is the same enzyme whose mildly reduced expression causes Gilbert's
syndrome, and the three conditions form one activity-loss spectrum rather
than distinct mechanisms.
role: trigger
biological_scale: MOLECULAR
conforms_to: "bilirubin_conjugation_transport#UGT1A1-Dependent Bilirubin Glucuronidation Deficiency"
genes:
- preferred_term: UGT1A1
term:
id: hgnc:12530
label: UGT1A1
cell_types:
- preferred_term: hepatocyte
term:
id: CL:0000182
label: hepatocyte
biological_processes:
- preferred_term: bilirubin conjugation
term:
id: GO:0006789
label: bilirubin conjugation
modifier: DECREASED
molecular_functions:
- preferred_term: glucuronosyltransferase activity
term:
id: GO:0015020
label: glucuronosyltransferase activity
modifier: DECREASED
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Crigler-Najjar Syndrome (CNS) is a rare genetic disorder caused by
mutations in the UGT1A1 gene, leading to impaired bilirubin conjugation
and severe unconjugated hyperbilirubinemia.
explanation: >-
States the gene, the enzymatic lesion, and the biochemical consequence
that define this node. Evidence source is OTHER because this is a scoping
review.
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
CNS presents in the following forms: CNS type 1 (CNS1), the more severe
form with the complete absence of UGT1A1 activity, and CNS type 2 (CNS2),
with partial enzyme activity.
explanation: >-
Establishes that residual enzyme activity is the variable distinguishing
the two subtypes, which is why they are curated as subtypes of one entry
rather than separate diseases. Evidence source is OTHER because this is a
scoping review.
- reference: PMID:25315738
reference_title: "Gene replacement therapy for genetic hepatocellular jaundice."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Crigler-Najjar syndrome is the severe inherited form of unconjugated
hyperbilirubinaemia due to mutations in the UGT1A1 gene, which can cause
kernicterus early in life and can be even lethal when left untreated.
explanation: >-
Independently confirms the genetic basis and places this disorder at the
severe end of the unconjugated hyperbilirubinaemia spectrum. Evidence
source is OTHER because this is a review.
downstream:
- target: Severe Unconjugated Hyperbilirubinaemia
causal_link_type: DIRECT
description: >-
Bilirubin that cannot be glucuronidated cannot be excreted in bile and
accumulates in plasma in the unconjugated form.
- name: Severe Unconjugated Hyperbilirubinaemia
description: >-
Unconjugated bilirubin accumulates in plasma to concentrations far above
those seen in Gilbert's syndrome, producing persistent non-haemolytic
jaundice from the first days of life. The defining biochemical picture is an
isolated unconjugated elevation: conjugated bilirubin, transaminases,
synthetic function, and liver imaging are normal, and there is no
haemolysis. This distinguishes Crigler-Najjar syndrome from liver disease
and from the conjugated hereditary hyperbilirubinaemias.
role: central_effector
biological_scale: ORGANISM
conforms_to: "bilirubin_conjugation_transport#Hyperbilirubinaemia"
biological_processes:
- preferred_term: bilirubin transport
term:
id: GO:0015723
label: bilirubin transport
modifier: DYSREGULATED
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Crigler–Najjar syndrome (CNS) is a rare autosomal recessive disorder
characterized by severe unconjugated hyperbilirubinemia. CNS results in
nonhemolytic jaundice, with its most serious complication being
bilirubin-induced neurologic dysfunction.
explanation: >-
States the biochemical phenotype of this node, its non-haemolytic nature,
and the complication that follows from it. Evidence source is OTHER
because this is a scoping review.
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Despite two weeks of treatment, unconjugated hyperbilirubinemia persisted,
with conjugated bilirubin levels below 0.7 mg/dL and unconjugated
bilirubin levels ranging from 22 to 25 mg/dL. No hemolysis or hepatic
dysfunction was observed.
explanation: >-
A worked human example of the isolated unconjugated pattern with normal
hepatic function and no haemolysis, the discriminating feature of this
node. Evidence source is HUMAN_CLINICAL because this is a patient case
report.
downstream:
- target: Bilirubin-Induced Neurological Dysfunction and Kernicterus
causal_link_type: DIRECT
description: >-
Unconjugated bilirubin in excess of albumin binding capacity crosses the
blood-brain barrier and binds brain tissue.
- name: Bilirubin-Induced Neurological Dysfunction and Kernicterus
description: >-
When plasma unconjugated bilirubin exceeds albumin binding capacity, the
free pigment crosses the blood-brain barrier and binds to specific brain
tissues, causing acute bilirubin encephalopathy and its chronic sequela,
kernicterus. This is the complication the whole management strategy exists
to prevent, and it is what makes type 1 a neonatal emergency. The risk is
strongly graded by subtype: it is high in type 1, where no enzyme activity
remains, and little to none in type 2. Once brain damage occurs it is
irreversible, which is why the timing of liver transplantation is critical.
role: consequence
biological_scale: ORGANISM
conforms_to: "bilirubin_conjugation_transport#Bilirubin Neurotoxicity and Kernicterus"
cell_types:
- preferred_term: neuron
term:
id: CL:0000540
label: neuron
locations:
- preferred_term: basal ganglion
term:
id: UBERON:0002420
label: basal ganglion
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
This occurs when bilirubin crosses the blood–brain barrier and binds to
specific brain tissues.
explanation: >-
States the mechanism by which the hyperbilirubinaemia node produces this
neurological consequence. Evidence source is OTHER because this is a
scoping review.
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Type I disease (CNS1) is characterized by severe jaundice and a high risk
of neurologic sequelae (kernicterus), resulting from the complete absence
of enzymatic activity; type II disease (CNS2) is a milder form with
decreased enzyme activity, lower serum bilirubin levels, and little to no
risk of kernicterus
explanation: >-
Grades the risk of reaching this node by subtype and ties that grading
back to residual enzyme activity at the trigger node. Evidence source is
OTHER because this is a scoping review.
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
The timing of LT is critical, as it must be performed before the onset of
irreversible brain damage (kernicterus), making early intervention
essential.
explanation: >-
Establishes the irreversibility of this node's damage, which is the
clinical reason the entry curates it as a terminal consequence rather
than a treatable complication. Evidence source is OTHER because this is a
scoping review.
phenotypes:
- category: Clinical
name: Neonatal Jaundice
description: >-
Jaundice appears in the neonatal period and persists, in contrast to
physiological neonatal jaundice which resolves. It is non-haemolytic and
unaccompanied by hepatic dysfunction.
phenotype_term:
preferred_term: Prolonged neonatal jaundice
term:
id: HP:0006579
label: Prolonged neonatal jaundice
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
CNS results in nonhemolytic jaundice, with its most serious complication
being bilirubin-induced neurologic dysfunction.
explanation: >-
Supports the jaundice phenotype and its non-haemolytic character.
Evidence source is OTHER because this is a scoping review.
- category: Laboratory
name: Unconjugated Hyperbilirubinaemia
description: >-
Marked elevation of the unconjugated (indirect) bilirubin fraction with a
normal conjugated fraction. Levels reached in type 1 far exceed those of
Gilbert's syndrome and can approach or exceed 30 mg/dL without treatment.
phenotype_term:
preferred_term: Unconjugated hyperbilirubinemia
term:
id: HP:0008282
label: Unconjugated hyperbilirubinemia
evidence:
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Here we report a two-month-old Saudi girl who presented with persistent
unconjugated hyperbilirubinemia, reaching levels as high as 30 mg/dL
despite ineffective phototherapy.
explanation: >-
Documents the magnitude of the unconjugated elevation in untreated type 1
disease. Evidence source is HUMAN_CLINICAL because this is a patient case
report.
- category: Neurological
name: Kernicterus
description: >-
Chronic bilirubin encephalopathy from deposition of unconjugated bilirubin
in the basal ganglia and brainstem nuclei. High risk in type 1, little to no
risk in type 2.
subtype: Type 1
phenotype_term:
preferred_term: Kernicterus
term:
id: HP:0001343
label: Kernicterus
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Type I disease (CNS1) is characterized by severe jaundice and a high risk
of neurologic sequelae (kernicterus), resulting from the complete absence
of enzymatic activity
explanation: >-
Assigns the kernicterus phenotype specifically to type 1 and ties it to
complete enzyme loss. Evidence source is OTHER because this is a scoping
review.
biochemical:
- name: Unconjugated Bilirubin
presence: INCREASED
context: >-
Markedly elevated unconjugated (indirect) serum bilirubin with a normal
conjugated fraction, normal transaminases and synthetic function, and no
evidence of haemolysis. In untreated type 1 disease levels of 22-30 mg/dL
are reported; treatment aims to hold total bilirubin below roughly 8.7
mg/dL, the threshold used clinically to avoid bilirubin encephalopathy.
biomarker_term:
preferred_term: unconjugated bilirubin
term:
id: CHEBI:16990
label: bilirubin IXalpha
readouts:
- target: Complete or Severe Loss of UGT1A1 Glucuronidation Activity
relationship: READOUT_OF
direction: POSITIVE
endpoint_context: DIAGNOSTIC
interpretation: >-
The isolated unconjugated elevation, with normal conjugated bilirubin and
normal hepatic function, reports loss of the UGT1A1 conjugation step
rather than liver disease or a transport defect.
evidence:
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Despite two weeks of treatment, unconjugated hyperbilirubinemia
persisted, with conjugated bilirubin levels below 0.7 mg/dL and
unconjugated bilirubin levels ranging from 22 to 25 mg/dL. No hemolysis
or hepatic dysfunction was observed.
explanation: >-
Documents the discriminating biochemical pattern in a genetically
confirmed patient. Evidence source is HUMAN_CLINICAL because this is a
case report.
genetic:
- name: UGT1A1
notes: >-
Biallelic pathogenic variants in UGT1A1, on chromosome 2q37, cause
Crigler-Najjar syndrome. Variants abolishing enzyme activity produce type 1;
those leaving residual activity produce type 2. The gene is the same one in
which a promoter TA-repeat polymorphism causes Gilbert's syndrome.
gene_term:
preferred_term: UGT1A1
term:
id: hgnc:12530
label: UGT1A1
relationship_type: CAUSATIVE
evidence:
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Both Crigler-Najjar syndrome (CNS) type I and CNS type II are hereditary
conditions characterized by elevated levels of unconjugated bilirubin due
to mutations in the UGT1A1 gene located on chromosome 2q37
explanation: >-
Establishes UGT1A1 as the causal gene for both subtypes and gives its
chromosomal location. Evidence source is HUMAN_CLINICAL because the
statement frames a genetically confirmed patient report.
inheritance:
- name: Autosomal recessive inheritance
description: >-
Crigler-Najjar syndrome is inherited in an autosomal recessive manner;
consanguinity is a recognised risk factor and the disorder is
over-represented in genetically isolated populations.
inheritance_term:
preferred_term: Autosomal recessive inheritance
term:
id: HP:0000007
label: Autosomal recessive inheritance
evidence:
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
CNS type 1 is inherited as an autosomal recessive disorder affecting
bilirubin conjugation
explanation: >-
States the mode of inheritance. Evidence source is HUMAN_CLINICAL because
this is a case report with pedigree analysis.
treatments:
- name: Intensive Phototherapy
description: >-
Prolonged daily phototherapy photoisomerises unconjugated bilirubin in the
skin into water-soluble products excretable without glucuronidation,
bypassing the missing enzyme. In type 1 it is containment rather than cure -
16-20 hours daily may be needed - and its efficacy declines with age as the
surface-area-to-mass ratio falls. It does not restore UGT1A1 activity.
therapeutic_modality: DEVICE
treatment_term:
preferred_term: Phototherapy
term:
id: NCIT:C15301
label: Phototherapy
target_mechanisms:
- target: Severe Unconjugated Hyperbilirubinaemia
treatment_effect: INHIBITS
description: >-
Photoisomerisation provides a conjugation-independent excretion route,
lowering plasma unconjugated bilirubin below the neurotoxic threshold.
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
The literature analysis showed that CNS1 requires aggressive management,
including phototherapy and plasmapheresis, but liver transplantation
(LT) remains the only definitive cure.
explanation: >-
Places phototherapy as containment of the hyperbilirubinaemia node and
explicitly distinguishes it from definitive treatment. Evidence source
is OTHER because this is a scoping review.
evidence:
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
While phototherapy offers some benefits, liver transplantation remains the
only definitive treatment for this condition.
explanation: >-
Marked PARTIAL because it bounds the claim - phototherapy helps but does
not cure, and in this reported patient it failed to control bilirubin.
Evidence source is HUMAN_CLINICAL because this is a case report.
- name: Phenobarbital
description: >-
Phenobarbital induces residual UGT1A1 expression and so lowers serum
bilirubin in type 2 disease. It is ineffective in type 1, where no enzyme
activity remains to be induced - a therapeutic distinction that follows
directly from the subtype's underlying enzymatic lesion, and one that makes
the response to phenobarbital diagnostically informative.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: phenobarbital
term:
id: CHEBI:8069
label: phenobarbital
target_mechanisms:
- target: Complete or Severe Loss of UGT1A1 Glucuronidation Activity
treatment_effect: ACTIVATES
description: >-
Enzyme induction raises the activity of the residual UGT1A1 present in
type 2 disease, partially restoring bilirubin conjugation. There is no
such residual activity in type 1, so this link applies only to type 2.
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
CNS2 is milder, with patients responding well to phenobarbital and
having a lower risk of kernicterus.
explanation: >-
Establishes the subtype-restricted efficacy of phenobarbital. Evidence
source is OTHER because this is a scoping review.
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
Current therapeutic options for CNS include phototherapy, phenobarbital
administration, and liver transplantation.
explanation: >-
Lists phenobarbital among the established therapeutic options. Evidence
source is OTHER because this is a scoping review.
- name: Liver Transplantation
description: >-
Orthotopic liver transplantation replaces the enzyme-deficient hepatocyte
population and is the only definitive cure for type 1 disease. It corrects
the lesion at its source rather than containing its downstream product, and
bilirubin normalises after transplantation. Timing is the critical variable:
it must precede irreversible kernicterus. The costs are the standard ones -
graft rejection and lifelong immunosuppression.
therapeutic_modality: SURGERY
treatment_term:
preferred_term: Organ Transplantation
term:
id: NCIT:C15289
label: Organ Transplantation
target_mechanisms:
- target: Complete or Severe Loss of UGT1A1 Glucuronidation Activity
treatment_effect: ACTIVATES
description: >-
Replacing the liver supplies hepatocytes with functional UGT1A1,
restoring bilirubin glucuronidation at the trigger node.
evidence:
- reference: PMID:37602038
reference_title: "Liver Transplantation in a Child With Crigler-Najjar Syndrome Type I: A Case Report With Review of the Literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The surgery was successful without complications, and the infant's
bilirubin levels normalized post-transplantation, with unconjugated
bilirubin levels at 0.64 mg/dL and conjugated bilirubin at 0.26 mg/dL.
explanation: >-
Demonstrates restoration of normal bilirubin handling after
transplantation, confirming the enzymatic lesion is hepatocyte-intrinsic
and correctable by liver replacement. Evidence source is HUMAN_CLINICAL
because this is a patient case report with post-operative laboratory
follow-up.
evidence:
- reference: PMID:39456788
reference_title: "Therapeutic Options for Crigler-Najjar Syndrome: A Scoping Review."
supports: SUPPORT
evidence_source: OTHER
snippet: >-
However, LT poses risks such as graft rejection and lifelong
immunosuppression.
explanation: >-
Marked PARTIAL because it records the cost side of the only curative
option, which is what motivates the investigational alternatives.
Evidence source is OTHER because this is a scoping review.
discussions:
- discussion_id: cn_gene_therapy_investigational
kind: KNOWLEDGE_GAP
prompt: >-
Can AAV-mediated UGT1A1 gene transfer or autologous hepatocyte
transplantation replace liver transplantation in Crigler-Najjar syndrome
type 1?
attaches_to:
- "pathophysiology#Complete or Severe Loss of UGT1A1 Glucuronidation Activity"
rationale: >-
Both alternatives target the enzymatic lesion itself rather than containing
its downstream product, which is what liver transplantation currently
requires major surgery and lifelong immunosuppression to achieve. Neither is
established. AAV gene therapy has shown potential in preclinical studies but
faces two problems specific to this disease: the target population is
paediatric, and a growing liver dilutes non-integrating vector genomes, and
pre-existing anti-AAV immunity restricts eligibility. Autologous hepatocyte
transplantation avoids rejection but durable engraftment has not been
demonstrated. These should be curated as investigational, not as available
treatments.
proposed_experiments:
- experiment_id: cn_aav_paediatric_durability
name: Paediatric durability study of AAV-UGT1A1 gene transfer
description: >-
Long-term follow-up of AAV-mediated UGT1A1 transfer dosed in early
childhood, reporting sustained bilirubin control and freedom from
phototherapy through the period of maximal liver growth, would establish
whether vector dilution defeats the approach in the population that needs
it most.