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.