Fatal acute hepatic failure in a family infected with the hepatitis A virus subgenotype IB

RATIONALE: Hepatitis A viral infection is a well-known cause of subclinical or acute self-limited hepatitis. Few cases of hepatitis A virus (HAV)-associated acute liver failure (ALF) have been reported in low HAV endemic countries annually. PATIENTS CONCERNS: To investigate the possible factors that affected the severity of HAV infection, a family cluster infected with the HAV subgenotype IB strain, which is not common in Japan, was described. DIAGNOSES: This family consisted of five members who all were infected with HAV. INTERVENTIONS: Four of the five patients hospitalized except for an asymptomatic patient. OUTCOMES: Two of the five patients, men in their 50s and 60s, developed ALF, and one patient died. Various host factors, including sex (male), age, and a high bilirubin level, may affect the outcomes. Based on viral factors, HAV RNA was higher in the fatal case compared with others, and it decreased within a short period of time. The similarity of the nucleotide sequences was 99.9% among the HAV isolates based on an entire genomic sequence. Deletions and/or insertions on the HAV protein-coding sequences that caused a frameshift were found in surviving cases but not in the fatal case. LESSONS: The rapid clearance of increased HAV and the absence of defective HAV might be closely associated with the onset of liver failure.