Primary Biliary Cirrhosis

It consists of a chronic progressive liver disease characterized by autoimmune destruction of the bile ducts that will eventually lead to cirrhosis. It is rare with an estimated incidence of 0.03%. It does not usually present with symptoms at diagnosis, or it will be treated in an insidious clinical form, however, it is frequently accompanied by other autoimmune pathologies.

The exact causes that trigger primary biliary cirrhosis are unknown, however, studies suggest that certain environmental factors may be responsible for triggering the autoimmune response in genetically predisposed individuals. These environmental factors include infections such as urinary tract infections, smoking or exposure to chemicals.

Additionally, gender seems to act as a risk factor since it affects women in a higher proportion. There also appears to be a higher frequency in people of northern European descent, although it can occur in people of any ethnicity.

In the absence of effective immunomodulatory therapy, the risk of severe liver failure and the need for transplantation is increased. In this context, recent meta-analysis of existing GWAS including 10500 cases and 62000 controls in order to identify risk loci and the evaluation of the efficacy of potential new treatments based on these, has revealed 38 significant loci that areIn addition, the identification of 38 significant loci involved in the immunological pathways of pattern receptor recognition, TNF and JAK-STAT signaling, and Th1 and Th17 lymphocyte differentiation. In addition, it allowed the identification of potentially useful drugs for treatment, some of them already in use for other autoimmune disorders.

Symptoms

Many people have no symptoms in the early stages and diagnosis often occurs between the ages of 35-70 years through routine screening.

In slightly more advanced cases there may be nonspecific manifestations:

  • Tiredness or fatigue.
  • Itching or generalized itching.
  • Dryness of mucous membranes, darkening of the skin.
  • Abdominal, muscular or joint pain.
  • Presence of xanthomas (yellowish-white plaques around the eyes).

As the disease progresses, in more advanced stages other symptoms may be observed such as:

  • Jaundice (yellowing of the skin and whites of the eyes).
  • Swelling of the legs, ankles and feet.
  • Swelling of the abdomen due to fluid accumulation.
  • Bleeding in the upper part of the stomach or lower esophagus (varicose veins).
  • Nausea.
  • Weight loss.
  • Dark colored urine.

Prevention

Since the cause of PBC is not known, it cannot be prevented, however, the following measures can be taken to decrease liver damage and slow down progressive damage:

  • Quitting smoking and avoiding alcohol and other substances of abuse.
  • Follow a healthy and balanced diet:
    • Healthy food choices could include consuming foods rich in vitamins A, D, E and K and/or supplements of these vitamins. In addition, foods rich in vitamin D and calcium may help prevent osteoporosis.
    • Foods to avoid include raw seafood (because of the possible presence of bacteria), foods high in salt, fats and carbohydrates, especially added sugars.
  • Exercise regularly, at least walking 30 minutes a day.

Number of observed variants

13.5 million variants

Number of risk loci analyzed in the study

38 loci

Bibliography

Pandit S et al. Primary Biliary Cirrhosis.

Carrion AF et al. Understanding and treating pruritus in primary biliary cholangitis. Clinical Liver Disease. 2018;22(3):517.

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