Table 2: Main features of familial Primary Biliary Cirrhosis (PBC).

Prevalence of PBC is increased in families with members affected by PBC. Prevalence rates range from 4 to 6%

Most affected members of the same family are females, with the most common pairing being in mother-daughters or sister-sisters

PBC rarely affects males, with few confirmed case reports of males relatives being affected

Increased incidence of autoimmune disease in families of PBC patients, most commonly Sicca syndrome and autoimmune thyroid disease

Diagnosis of a second or more family member often occurs within a short time interval of the initial case. This may be due to early screening for cholestasis or AMA initiated by the initial diagnosis

Concordance rates among monozygotic twins are among the highest of the autoimmune diseases

PBC in extended families (i.e., family members not related genetically) is rare, but has been reported mainly in husband and wife pairs, but at least one reports PBC in a female and her mother-in-law

Studies in support of the main findings in families of patients with PBC are discussed in the main text; AMA: antimitochondrial antibody.