Variable degree of liver involvement in siblings with PiZZ alpha-1-antitrypsin deficiency-related liver disease

Area of Science:

• Genetics
• Hepatology
• Pediatrics

Background:

• Alpha-1 antitrypsin deficiency (A1ATD) is a common genetic disorder.
• The PiZZ phenotype is the most frequent genetic cause of chronic liver disease.
• Liver disease develops in only 10-15% of PiZZ individuals, often in childhood.

Purpose of the Study:

• To investigate the variability of liver disease presentation in siblings with the PiZZ phenotype.
• To compare liver disease patterns between affected siblings diagnosed with PiZZ A1ATD.

Main Methods:

• Retrospective analysis of case notes for patients diagnosed with PiZZ A1ATD between 1978-2002.
• Identification of families with multiple children exhibiting the PiZZ phenotype.
• Comparison of liver disease severity and progression among siblings.

Main Results:

• 29 families with multiple PiZZ children were identified.
• 72% of PiZZ siblings (21/29) presented with liver disease.
• Liver disease severity was concordant in only 29% (6/21) of affected siblings, with 28% (8/29) showing no liver involvement.
• Five of seven children requiring liver transplantation had siblings without persistent liver dysfunction.

Conclusions:

• Sibling concordance for liver disease severity in PiZZ A1ATD is low.
• Significant variability exists in liver involvement among siblings with PiZZ A1ATD.
• Environmental and/or additional genetic factors likely play a crucial role in determining disease severity.