PFIC is a group of autosomal recessive disorders that impair bile formation, leading to progressive cholestasis, liver failure, and cirrhosis. Each subtype has distinct genetic, histologic, and clinical features. BRIC is a milder, intermittent form of cholestasis without progression to cirrhosis.
| Feature | PFIC Type 1 | PFIC Type 2 | PFIC Type 3 | PFIC (TJP2) |
|---|---|---|---|---|
| Gene | ATP8B1 (18q21-22) | ABCB11/BSEP (2q24) | ABCB4/MDR3 (7q21) | TJP2 (9q21) |
| Protein Location | Apical membranes of hepatocytes, intestine, pancreas, colon | Canalicular membrane of hepatocytes | Canalicular membrane of hepatocytes | Tight junctions between hepatocytes and canaliculi |
| Histology | Bland cholestasis, “Byler bile” on EM | Giant cell hepatitis, amorphous bile on EM | Bile duct proliferation, periportal bile on EM | Elongated tight junctions, absent zona occludens |
| GGT Levels | Normal or low | Normal or low | Elevated | Normal or low |
| Bile Acids | ↑ serum, ↓ biliary | ↑ serum, ↓ biliary | Normal biliary bile acids | ↑ serum bile acids |
| Clinical Features | Pruritus, diarrhea, steatorrhea, growth failure, hearing loss | Rapid cholestasis, pruritus, vitamin deficiency, growth failure | Later onset, mild pruritus, portal hypertension, gallstones | Early severe cholestasis, end-stage liver disease before adulthood |
| Cancer Risk | Low | ↑ risk of HCC/cholangiocarcinoma | Possible with progression | Unknown |
| Treatment | Supportive, antipruritic, biliary diversion, transplant | Supportive, antipruritic, biliary diversion, transplant | Ursodeoxycholic acid, transplant | Supportive, antipruritic, transplant |
Management includes:
Medical therapy: Ursodeoxycholic acid, rifampin, cholestyramine, and nutritional support
Surgical options: Partial external biliary diversion (PEBD) or ileal exclusion
Liver transplantation: Required in advanced cases or when medical/surgical therapy fails
PFIC2 patients may require early transplantation due to rapid progression and cancer risk.
Prognosis varies by subtype:
PFIC1 and PFIC2 often progress to liver failure in childhood.
PFIC3 may have a slower progression.
Early diagnosis and intervention improve outcomes.
| Feature | BRIC | PFIC |
|---|---|---|
| Inheritance | Autosomal recessive | Autosomal recessive |
| Genes | ATP8B1, ABCB11 | ATP8B1, ABCB11, ABCB4, TJP2 |
| Onset | Childhood or adolescence | Infancy or early childhood |
| Course | Intermittent episodes | Progressive and chronic |
| Liver Damage | No permanent damage | Progresses to cirrhosis and liver failure |
| GGT Levels | Normal | Normal or elevated (depends on subtype) |
| Treatment | Supportive care, antipruritic agents | Medical therapy, surgical diversion, liver transplant |
| Prognosis | Excellent | Variable; often poor without intervention |