Relationship of familial cytochrome P450 4V2 gene mutation with liver cirrhosis: A case report and review of the literature

BACKGROUND Many genetic and metabolic diseases affect the liver, but diagnosis can be difficult because these diseases may have complex clinical manifestations and diverse clinical patterns. There is also incomplete clinical knowledge of these many different diseases and limitations of current testing methods. CASE SUMMARY We report a 53-year-old female from a rural area in China who was hospitalized for lower limb edema, abdominal distension, cirrhosis, and hypothyroidism. We excluded the common causes of liver disease (drinking alcohol, using traditional Chinese medicines, hepatitis virus infection, autoimmunity, and hepatolenticular degeneration). When she was 23-years-old, she developed night-blindness that worsened to complete blindness, with no obvious cause. Her parents were first cousins, and both were alive. Analysis of the patient's family history indicated that all 5 siblings had night blindness and impaired vision; one sister was completely blind; and another sister had night-blindness complicated with cirrhosis and subclinical hypothyroidism. Entire exome sequencing showed that the patient, parents, and siblings all had mutations in the cytochrome P450 4V2 gene (CYP4V2). The CYP4V2 mutations of the parents and two sisters were heterozygous, and the others were homozygous. Two siblings also had heterozygous dual oxidase activator 2 (DUOXA2) mutations. CONCLUSION Mutations in the CYP4V2 gene may affect lipid metabolism and lead to chronic liver injury, fibrosis, and cirrhosis.