Genetics and Liver Disease - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Genetics explains how living organisms get their features or certain characteristics from their parents. A gene determines a character and certain features, like the type of hair, the color of eyes, and other features, from the parent to the children. Certain diseases also have a genetic connection and run in the family.

Genetically inherited liver diseases are hemochromatosis (excess iron storage in the liver), alpha-1 antitrypsin deficiency (a protein called alpha-1 antitrypsin is less than normal levels in the blood), Wilson's disease (excess storage of copper in the liver), tyrosinemia type 1 (due to abnormal build-up of the enzyme tyrosine in the liver), glycogen storage disease type 4 (deposition of a type of sugar called glycogen in the liver), and hereditary fructose intolerance (building up of toxic substances in the liver due to downfall in the blood sugar).

What Is Genetics?

Genetics is a division of science that explains how certain characteristic features are transferred from one generation to the other. Genes are substances that carry information like hair type, the color of the eyes, certain facial features, and some behavioral characteristics. Genes are made of sequences of DNA (deoxyribonucleic acid) which are arranged one after the other.

What Are Genetic Liver Diseases?

Genetic liver diseases are diseases inherited from the parent or a member of the family. The genetically inherited liver diseases are:

• Hemochromatosis (excess iron storage in the liver).

• Alpha-1 antitrypsin deficiency (a protein called alpha-1 antitrypsin is less than normal levels in the blood).

• Wilson’s disease (excess storage of copper in the liver).

• Tyrosinemia type 1 (due to an abnormal build-up of the enzyme tyrosine in the liver).

• Glycogen storage disease type 4 (deposition of a type of sugar called glycogen in the liver).

• Hereditary fructose intolerance (building up of toxic substances in the liver due to a downfall in the blood sugar).

What Are the Causes of Genetic Disease?

Genetic diseases are caused due to mutations (changes in the structure) of the DNA. It can be changed in the sequence of the DNA or can damage the DNA by getting exposed to external factors like cigarette smoking, radiation from the sun, some industrial chemicals, and food mutagens (mutagens from charred meat and fish when cooked in high temperatures). Mutagens are substances that cause a gene to mutate when exposed to some chemicals like chemicals present in baking food or fried food, ultraviolet radiation (radiation coming from the sun or artificial sources), or X-ray radiation (radiation exposed while taking an X-ray).

What Is Hemochromatosis?

Hemochromatosis is the excess storage of iron in the liver from the food that is consumed. This is a genetically inherited disease and leads to the high absorption of the liver from food.

What Causes Hemochromatosis?

It is caused by the mutation in the gene HFE (hemostatic iron regulator), which controls the iron absorption from food. This gene is inherited or obtained from the parents. If both the HFE genes from the parents are abnormal, the chances of getting hemochromatosis are high. If one HFE gene is abnormal, the person might get hemochromatosis, and they will be carriers and pass on this abnormal gene to their children.

What Are the Symptoms of Hemochromatosis?

• Joint pain.

• Pain in the abdominal region.

• Feeling weak and tired.

• Heart failure.

• Skin color changes to bronze color.

• Loss of sexual urge.

• Hazy memory.

How Is Hemochromatosis Found?

• Serum Ferritin: This test shows the amount of iron stored in the liver.

• Serum Transferrin saturation: This test shows the amount of iron stuck with a protein called transferrin. This transferrin carries iron in the blood.

• Liver Function Tests: Liver function tests are blood tests that screen the liver enzymes, proteins, and prothrombin time. Liver enzymes like alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transaminase (GGT), and proteins like albumin and globulin are screened for diagnosing liver disease. The changes in the normal values of these enzymes and proteins suggest liver disease.

• Testing for Gene Mutations: Gene mutation test for HFE is done if the iron levels are too high in the blood to rule out hemochromatosis.

• MRI Scan: Magnetic resonance imaging (MRI) scan uses a combination of strong magnetic fields and radio waves to capture images of the internal organs and structures. This technique provides a detailed view of the targeted structure.

• Liver Biopsy: Liver biopsy removes a tiny portion of liver tissue to view pathological changes in a microscopic view. This is a confirmatory test and reveals the type of liver disease.

How Is Hemochromatosis Treated?

• Blood Removal: Hemochromatosis is treated by removing the blood through the veins. This is done to reduce the iron present in the blood. This procedure will be done one to two times a week initially. Then when the iron levels are normal, the blood removal will be done once in two to three months.

• Chelating Agents: In some cases, if the patient has anemia (reduced healthy red blood cells in the blood) or patients with heart diseases, blood removal can lead to complications. In these types of patients, a medication that removes excess iron from the blood is injected or given orally. It removes the excess iron through urine or stools, and this is called chelation.

What Is Alpha-1 Antitrypsin (AAT) Deficiency?

Alpha-1 antitrypsin is a protein that protects the lung and is produced by the liver. In a genetically inherited condition, alpha-1 antitrypsin is deficient and leads to liver and lung damage. The alpha-1 antitrypsin protein controls the action of the enzyme neutrophil esterase. This enzyme is released by the white blood cells to fight infections, but they also damage normal tissues if not restricted by alpha-1 antitrypsin.

What Causes Alpha-1 Antitrypsin Deficiency?

The gene serpina 1 provides information for the formation of alpha-1 antitrypsin. The mutation in serpina 1 causes deficit alpha-1 antitrypsin, and the neutrophil esterase enzymes are out of control. These enzymes damage the lung tissues and cause lung damage. This also causes the accumulation of alpha-1 antitrypsin in the liver and results in liver damage.

What Are the Symptoms of Alpha-1 Antitrypsin Deficiency?

• Shortness of breath on minimal work.

• Wheezing.

• Unable to exercise.

• Feeling weak and tired.

• Repeated respiratory infections.

• Unexplained weight loss.

• Emphysema (damage to small air-filled sacs called alveoli).

How Is Alpha-1 Antitrypsin Deficiency Found?

• Blood Test: A blood test is performed to screen the AAT levels in the blood. If the levels are below the normal range, AAT deficiency is ruled.

• Genetic Test: A genetic test is performed to determine AAT mutation.

• Spirometry: It is a lung function test to determine how much a person can inhale and exhale quickly.

• CT-Scan Chest: Computerized tomography (CT) is an imaging technique that contains cross-sectional X-ray images of the lungs at various angles captured digitally on a computer. It gives a detailed view of the targeted structure to view any abnormality.

How Is Alpha-1 Antitrypsin Deficiency Treated?

There is no specific treatment for alpha-1 antitrypsin deficiency, but replacement therapy can improve lung conditions.

Augmentation Therapy: Augmentation or replacement therapy involves replacing the alpha-1 antitrypsin from a donor's blood. Blood is transferred from a donor to the patient with alpha-1 antitrypsin deficiency through the veins. The reduced alpha-1 antitrypsin will be replaced. This reduces lung and liver damage.

What Is Wilson's Disease?

Wilson’s disease is the abnormal accumulation of copper in the liver.

What Causes Wilson's Disease?

The liver removes waste products, toxins, and other elements like copper through the bile and digestive system. However, a mutation of gene ATP 7 prevents the complete elimination of copper from the liver. This incomplete elimination leads to too much storage of copper in the liver.

What Are the Symptoms of Wilson’s Disease?

• Feeling weak and tired.

• Yellowish discoloration of the skin and eyes.

• Ascites (stomach enlargement due to fluid accumulation).

• Edema (swelling in the legs due to fluid accumulation).

• Troubled speech.

• Golden-brown discoloration of the eyes (Kayser-Fleischer ring).

• Muscle stiffness.

How Can Wilson’s Disease Be Found?

• Physical Examination: Physical examination is done by the doctor to check for enlarged liver, swelling or pain in the stomach, and swelling in the legs.

• Eye Examination: A special light is used to check the Kayser-Fleischer ring in the eyes.

• Blood Test: A blood test is performed to screen the protein ceruloplasmin that carries copper in the blood circulation.

• Urine Sample Test: This is done to screen for the presence of copper in the urine.

• Liver Function Tests: Liver function tests are a group of tests that include the screening of liver enzymes, proteins, and prothrombin time. Liver enzymes like alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transaminase (GGT), and proteins like albumin and globulin are screened for diagnosing liver disease. The changes in the normal values of these enzymes and proteins suggest liver disease.

• CT Scan: Computerized tomography (CT) is a series of X-ray images taken from different angles of the body. It provides a detailed image of the structures captured. CT scan helps find out liver disease.

• MRI Scan: Magnetic resonance imaging (MRI) uses a combination of a strong magnetic field and high-frequency radio waves to capture the internal structures in our body. This scan provides a more detailed image of the structure to find out the disease.

• Liver Biopsy: Liver biopsy involves the removal of a very small part of the liver tissue to view the changes at a microscopic level. The result of this test provides the details of the type of the disease. This is a confirmatory test.

How Is Wilson’s Disease Treated?

• Medications: Medications like Zinc are prescribed, as it prevents the absorption of copper in the intestine.

• Chelating Agents: Chelating agents like Penicillamine are prescribed, as it helps remove the excess copper from the body.

What Is Tyrosinemia Type 1?

Tyrosinemia type I is an abnormal build-up of the enzyme tyrosine in the liver.

What Causes Tyrosinemia Type 1?

Tyrosinemia type 1 is caused due to deficiency of the enzyme fumarylacetoacetate hydrolase (FAH). This enzyme helps in the final breakdown of tyrosinemia, which is a building block for most proteins. This unsuccessful breakdown leads to the accumulation of tyrosine in the liver.

What Are the Symptoms of Tyrosinemia Type 1?

The symptoms usually occur within a few months of birth.

• Failure to gain weight.

• Failure to show growth at the expected rate.

• Jaundice (the skin and eyes appear yellow in color).

• Fever.

• Diarrhea.

• Vomiting.

• Enlarged liver.

• Easy bruising and bleeding.

How Is Tyrosinemia Type 1 Ruled?

• Physical Examination: A physical examination is performed by the doctor to check for enlarged liver.

• Urine Test: A urine test is done to check for the presence of tyrosine and succinylacetone.

• Genetic Test: A genetic test is performed to determine mutations in FAH.

• Liver Biopsy: Liver biopsy involves the removal of a very small part of the liver tissue to view the changes at a microscopic level. The result of this test provides the details of the type of the disease. This is a confirmatory test.

What Is the Treatment of Tyrosinemia Type 1?

• Medications: Medications like Nitisinone capsule or syrup form are prescribed.

• Diet: A low-protein diet along with the medication has to be followed.

What Is Glycogen Storage Disease Type 4?

The sugar (glucose) is absorbed from the food we take. The body uses sugar for energy. The excess sugar present in the circulation is stocked in the liver in the form of glycogen for later use. The glycogen breaks down into glucose (sugar) when needed by the body with the help of glycogen branching enzymes (GBE). The GBE1 enzymes instruct glycogen production. The mutation in GBE1 prevents the production of glycogen. This leads to a deficit in the glycogen, and abnormal glycogen molecules are formed and get stored in the liver. This results in cell damage and cell death.

What Are the Symptoms of Glycogen Storage Disease Type 4?

• Failure to grow normally.

• Low blood sugar levels.

• Enlarged liver.

• Enlarged stomach.

• Muscle weakness.

• Muscle pain or muscle cramps while doing exercise.

• Intolerant to heat.

• Easy bruising.

• Feeling weak and tired.

How Is Glycogen Storage Disease Type 4 Ruled?

• Blood Test: Blood tests are performed to screen blood sugar levels.

• Ultrasound Abdomen: A high-frequency sound wave is used to capture images of structures or organs inside the body.

• Tissue Biopsy: Tissue biopsy involves the removal of a very small part of the liver tissue or muscle tissue to view the changes at a microscopic level. The result of this test provides the details of the type of the disease.

• Gene Testing: A genetic test is performed to determine mutations in GBE1.

How Is Glycogen Storage Disease Treated?

• Regular intake of uncooked starch. Uncooked starch is a complex carbohydrate that is difficult to digest and remains in the system for a long time, thus maintaining a normal blood sugar level in the blood.

• Nutritional supplements like vitamins and minerals.

• Liver transplant.

What Is Hereditary Fructose Intolerance?

Hereditary fructose intolerance happens when the enzyme aldolase B needed to break down fructose is absent in a person. Fructose is a type of fruit sugar naturally present in our bodies. Fructose is used to sweeten many food items and in baby foods. When a person consumes foods that contain fructose, the body cannot convert glycogen to glucose. This will result in low blood sugar levels in the blood and the accumulation of harmful substances in the liver. This is a hereditary disease that runs in the family.

What Are the Symptoms of Hereditary Fructose Intolerance?

• Vomiting.

• Retarded growth.

• Yellowish discoloration of the skin and eyes.

• Becoming unconscious sometimes.

• Enlarged liver.

• Excess sleepiness.

• Seizures.

How Is Hereditary Fructose Intolerance Found?

• Physical Examination: A physical examination is performed by the doctor to check for enlarged liver.

• Liver Function Tests: Liver function tests are a group of tests that include the screening of liver enzymes, proteins, and prothrombin time. Liver enzymes like alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transaminase (GGT), and proteins like albumin and globulin are screened for diagnosing liver disease.

• Blood Test: Blood tests are performed to screen blood sugar levels.

• Liver Biopsy: Liver biopsy involves the removal of a very small part of the liver tissue to view the changes at a microscopic level. The result of this test provides the details of the type of the disease.

• Kidney Function Test: A kidney function test is used to check the levels of blood urea nitrogen (screens nitrogen in the blood), estimated glomerular filtration rate (estimates the filtration rate depending on the protein level, age, gender, and size), serum creatinine (screens creatinine level in the blood which is a muscle breakdown waste product).

• Uric Acid Blood Test: This test determines the amount of uric acid (a chemical that results due to purine processing) available in the blood.

• Urinalysis: This test is done to check for the physical, chemical, and microscopic examination of components in the urine.

What Is the Treatment of Hereditary Fructose Intolerance?

• The treatment involves avoiding food that contains fructose.

Can Genetic Disease Be Prevented?

Since the origin of the disease is due to genetic reasons, it cannot be prevented.

Conclusion:

Genetic diseases run in the family, or any one member of the family might be affected by the disease. The gene carrying the same information will be passed on to the next generation. If the next generation person has two abnormal genes, the individual will get the genetic liver disease. If the person has only one abnormal gene, they might be a carrier and pass the disease to the next generation. Though genetic liver disease in some cases is fatal, getting a genetic test done if there is a history of genetic disease can help detect the disease. This will prevent delays in detecting the disease and start with appropriate treatment for a long healthy life.