About VHL

OVERVIEW

Von Hippel-Lindau Disease (VHL) is an autosomal dominant disorder that causes the formation of cysts and tumors on the kidneys, retinas, and central nervous system. Autosomal dominant comes from two parts. Autosomal comes from the fact that the VHL gene is found on the short leg of chromosome 3, which is known as an autosome, and dominant comes from that an individual with the disease must have a parent that has the disease.


HISTORY

The disease was first noted by Eugen von Hippel, when he noticed tumors on his patients retinas in 1904. The tumors found on the brain and central nervous system were then described by Arvid Lindau in 1924. This disease is also speculated to have been a cause to the infamous Hatfield and McCoy feud of the 19th Century, because it is believed that the McCoy family had tumors on the adrenal glands due to VHL, which caused them to have heightened levels of adrenaline in their bodies, causing them to have explosive tempers.

RISK FACTORS

The only risk a person has to get this disorder is if a parent is either homozygous dominant (meaning they have the disease), or heterozygous (meaning the parent is a carrier). This punnett square shows visually the chances of getting VHL:

In this chart, the offspring that has VHL is the offspring with the genotype AA.


HOW IS THIS DISEASE CAUSED?

This disease is caused by a mutation in the VHL gene found on the short leg of chromosome 3. This mutation can be found in either the mother or the father, which allows the offspring double the chance to inherit the mutated gene.


SYMPTOMS

According to the U.S. Library of Medicine, the official name of the gene is “von Hippel-Lindau tumor suppressor, E3 ubiquitin protein ligase.” E3 ubiquitin protein ligase is the protein that is produced by this section of DNA. When this is altered, the person with that mutated gene starts to show the symptoms of VHL. The symptoms of VHL vary from case to case. However, most have tumors on the kidneys, pancreas, and spinal cord. Most of these tumors are noncancerous, but cancer can occur in the brain and kidneys from this disease. Overall, though, there are virtually no symptoms, save the tumors.

DIAGNOSIS

There are some tests that can be done to determine if someone has VHL:

• Physical Exam: A doctor will ask the patient about prior medical history before preforming a physical test. This is to check for tumors or cysts that is caused by this disorder.
• Blood Test: This test is done to scan the individual's DNA to look for mutations in the VHL gene.
• Magnetic Resonance Imaging (MRI): The MRI machine creates a magnetic field that scans the protons and hydrogen nuclei, due to the body being mostly made of water. The protons then absorb a second radio frequency that is released by an electromagnet found in the MRI machine. This test can show doctors if an individual has cysts or tumors that couldn't be found in the physical exam.
• Computed tomagraphy scan (CT scan): A CT machine scans a patients body using X-Rays. This data is fed into a computer that produces an image based off of the x-rays. This test can show doctors where tumors and cysts are similar to that of the MRI test.
• Ultrasound: This test uses sound waves that can bounce off of the tumors/cysts inside the body.
• Angiography: A test that uses a dye injected into the patient's bloodstream to check the arteries, since the tumors can start to form here.
• 24 Hour Urine Test: This test monitors the patient's urine to check for elevated hormone levels, as the tumors can cause this if they are located on certain glands.

TREATMENT

Treatment varies from person to person, depending on how severe that specific case is, general health, symptoms, and test results. Treatments include:

• Surgery (This is only done if the tumor being removed is cancerous or hazards the individual's health.
• Photocoagulation (The cauterization of ocular blood vessels in an effort to provide therapy)
• Cryocoagulation (The process of using water to freeze blood vessels in tumors)
• Regular Medical Exams

The goal of photocoagulation is to stop the blood flow of vessels entering a tumor by cauterizing them. Cauterization is the process of taking a special instrument to literally burn the ends of blood vessels to fuse them shut. This causes the cells in the tumor to die off, and be easily removed. In cryocoagulation, water is used to freeze blood vessels entering the tumors, similar to photocoagulation. 

PROGNOSIS

If the disease is caught early, treatment can be done to significantly help and individual with VHL. However, death can occur due to this disease, and is usually from complications with kidney or brain tumors. This disease usually does not affect the patient's social interaction with others, unless the tumors become widespread and cause discomfort or embarrassment for the individual. Emotionally, the patients are just like you and I, unless the tumors are on glands that excrete hormones that affect one's mood or emotions. For instance, if a tumor forms on a patient's adrenal gland, this makes them have a higher level of adrenaline in their bloodstream, causing them to be more "antsy" or agitated.


NUMBER OF CASES

This rare disease only affects 1 in 32,000 people according to the Von Hippel-Lindau Syndrome Family Alliance. This would put the number of cases at approximately 218,969 cases worldwide, and most of these cases aren't even documented.