Neonate Hemochromatosis

Definition And Pathophysiology

• Single most common cause of acute liver failure during first month of life.
• Not a primary iron overload disease; secondary to severe fetal liver injury.
• Driven by gestational alloimmune liver disease (GALD) in nearly all cases.
• Maternal immune system sensitized to unknown fetal hepatocyte cell surface antigen.
• Maternal immunoglobulin G (IgG) crosses placenta, binding fetal liver antigens.
• Activates terminal complement cascade, forming C5b-9 membrane attack complex.
• Induces massive hepatocyte injury and death.
• Fetal liver injury impairs synthesis of iron regulatory and transport proteins (hepcidin).
• Impaired regulation causes excess non-transferrin-bound iron.
• Results in extrahepatic siderosis dictated by normal tissue capacity to import non-transferrin-bound iron.
• High recurrence rate in families; >90% probability subsequent infants affected.

Clinical Manifestations

• Presents at birth or within first few days of life.
• Prematurity or intrauterine growth restriction common.
• Jaundice, hypoglycemia, severe coagulopathy refractory to vitamin K.
• Hypoalbuminemia.
• Transaminases normal or mildly elevated, out of proportion to degree of liver failure.

Diagnostic Evaluation

• High serum ferritin, elevated alpha-fetoprotein, raised iron saturation.
• Extrahepatic iron deposition spares reticuloendothelial system.
• Magnetic resonance imaging (MRI) demonstrates extrahepatic siderosis in pancreas, myocardium, or thyroid follicles.
• Salivary gland/buccal submucosal biopsy confirms extrahepatic siderosis safely.
• Liver biopsy reveals acute and chronic inflammation, fibrosis, cirrhosis, absent surviving hepatocytes.
• Positive immunohistochemical staining for C5b-9 membrane attack complex on liver tissue.

Management And Prevention

Acute Postnatal Management

• Antioxidant cocktail (N-acetylcysteine, selenium, desferrioxamine, prostaglandin E1, vitamin E) historically utilized for iron chelation/free radical scavenging; lacks proven benefit.
• Intravenous immunoglobulin (IVIG) administration (1 g/kg) combined with exchange transfusion.
• Exchange transfusion removes circulating maternal IgG.
• IVIG/exchange transfusion significantly decreases need for liver transplantation.
• Liver transplantation indicated for failed medical management.

Antenatal Prevention

• Indicated for mothers with previously affected pregnancy.
• Maternal IVIG administration (1 g/kg bodyweight weekly).
• Initiated at 18 weeks gestational age; continued until end of gestation.
• Decreases GALD in developing fetus; achieves milder phenotypic expression and 100% infant survival.

Hereditary And Juvenile Hemochromatosis

Pathophysiology Of Iron Transport

• Normal intestinal iron absorption utilizes heme carrier protein 1 (HCP1) and divalent metal transporter 1 (DMT1) for apical uptake.
• Iron efflux at basolateral enterocyte membrane mediated by ferroportin 1.
• Hepatic hormone hepcidin controls plasma iron levels.
• Hepcidin binds ferroportin, inducing phosphorylation, internalization, and degradation of iron exporter.
• Hepcidin deficiency causes unchecked iron absorption and systemic iron overload.

Genetic Classification

Clinical Manifestations

• Rare presentation in pediatric population.
• Progressive iron accumulation causes multiorgan dysfunction.
• Associated with bronze diabetes and arthropathy.
• Hepatomegaly, potential progression to cirrhosis.

Diagnostic Evaluation

• Markedly elevated serum ferritin and transferrin saturation.
• Hepatic iron content elevated on biopsy.
• HFE genetic testing confirms classic variants.

Differential Diagnosis Of Neonatal Liver Failure

Differentiating GALD/Neonatal Hemochromatosis from other acute neonatal liver failure etiologies requires careful biochemical correlation.