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Alport syndrome

The Alport syndrome is an inherited disorder characterized by damage collagen, which is a material formed by proteins that serves to form support structures of the different organs of the human body.

There are four different types of this disease, each with a different type of inheritance:

  1. Classic Alport syndrome, in which the defect is located on the X chromosome and is characterized by kidney disease, deafness, and conical deformation of the anterior surface of the lens.
  2. There is another form with defects in the X chromosome, but which causes a diffuse muscle alteration.
  3. A third form with autosomal dominant inheritance.
  4. A fourth form with autosomal recessive inheritance.

These last two forms can cause kidney involvement without deafness or eye disorders.

The incidence of this disorder is one case per 10,000 inhabitants and, although it produces alterations in different organs, the most important damage is in the kidney since it can lead to chronic renal failure, with which the patient will need to undergo dialysis or a kidney transplant.

This syndrome is therefore a hereditary disorder with involvement of different organs and that does not have an effective treatment.

Causes of Alport syndrome

There is no agent that causes this disease.

It is an inherited disorder in which a chromosome has a mutation in one of the genes that is responsible for carrying the information necessary for the production of the proteins that give rise to collagen. This altered gene is passed from parents to children depending on the type of inheritance.

This syndrome has three different types of inheritance:

  • the one associated with the X chromosome, in which women transmit the disease and men suffer from it
  • autosomal dominant, which no longer depends on sex, and in which the altered gene is dominant, so that all diseased individuals have a diseased parent, there are no individuals who transmit the disease without suffering from it, and a patient will have affected children and not affected in the same proportion
  • autosomal recessive, which is characterized by the fact that the altered gene is not dominant, so both genes must be altered to suffer from the disease, in this case healthy parents can have sick children if they are carriers and a sick father has healthy children Unless the other parent is a carrier or suffers from the disease.

Heredity is the only factor involved in the development of this disorder.

Alport syndrome is characterized by alterations in some of the genes responsible for the production of type IV collagen, which is the fundamental component of the basement membrane of different organs, mainly the kidney. The basement membrane is a structure that separates the epithelium from the rest of the structures that are behind it.

Type IV collagen is made up of several protein chains that take a helix shape with globular ends, giving this structure a cylindrical shape. The helix is ​​interrupted by short linear sequences, all of which represent a complex three-dimensional plot. Patients with this disorder have an alteration in one of the chromosomes that carry the genes responsible for the formation of type IV collagen proteins. These genes are found on several chromosomes (2, 13, X), but only one needs to be altered for the disease to occur. Thus, the collagen that is formed is unstructured and produces a basement membrane with a thickness up to five times greater than usual, with distortions and fissures in it.

This increase in the thickness of the basement membrane mainly affects the nephrons, which are the structures of the kidney that are responsible for filtering the blood and producing urine.

The nephron is a tubular structure with a leading end through which blood is filtered. The product of this filtrate passes into these tubules, where it undergoes various changes in its composition until urine originates, which is excreted from the kidney to the ureter and from here to the bladder. Blood filtering takes place in the glomerulus, which is a structure made up of blood capillaries and the beginning of the nephron. One of the filters involved is the glomerular basement membrane, which prevents different blood compounds (for example, red and white blood cells) from entering the tubules. When the basement membrane is altered, there is a destructuring of the entire glomerulus with sclerosis of the same and tubular fibrosis, in other areas atrophy or hypercellularity occurs.

You may also be interested in:   Membranoproliferative glomerulonephritis

Symptoms of Alport syndrome

Typical symptoms of Alport syndrome include:

  • deafness, which appears in 60% of cases, usually affects the high tones and is often required to detect an audiometry ; lens alterations (occur in 15% of patients)
  • Kidney disease (occurs in all cases), characterized by hematuria (blood in the urine) or microhematuria, the presence of protein in the urine and progressive renal failure, which leads the patient to dialysis or kidney transplantation.

In cases where transplantation occurs, 5% of patients will develop rejection of it, because the body recognizes the normal basement membrane of the grafted kidney as foreign.

This condition is sometimes associated with platelet defects, although it is rare.

Carrier women can have mild disease with microhematuria, but without developing kidney failure.

These patients will present the symptoms of kidney failure:

  • tiredness
  • decreased appetite
  • gastrointestinal upset
  • cramps
  • muscle pains
  • confusion
  • edema
  • arterial hypertension
  • pruritus (itching)

How is it diagnosed?

The diagnosis is based on the presence of symptoms. Thus, renal failure associated with deafness and alterations of the lens, ensure the diagnosis.
In patients with only renal involvement, the diagnosis is made with a kidney biopsy, which shows the alterations of the basement membrane typical of this disorder.

Audiometry is used for the diagnosis of hearing disorders.

Kidney failure is diagnosed with a blood test that shows elevations in plasma creatinine, as well as decreased creatinine clearance, which is what determines the degree of failure and at what time the patient should be put on dialysis until a transplant.

Alport syndrome treatment

Alport syndrome has no treatment as such, there is nothing we can do to avoid its alterations, and once they are established we cannot do anything to prevent progression.

There are a series of measures that we can take to avoid complications associated with kidney failure: we must monitor the levels of potassium , calcium and phosphorus, which tend to alter as the kidney is damaged; In addition, blood pressure must be monitored, which also tends to rise in these circumstances. All of these disorders can be treated to avoid major complications.

Once severe renal failure is established, the patient must undergo dialysis, which ensures the purification of the blood performing a function similar to that of the kidneys in good condition. Dialysis can be maintained for years while a compatible kidney appears that can be transplanted, since this is the definitive solution to kidney alterations, as long as there is no rejection.

How can I avoid it?

Alport syndrome, as we have already said, is a hereditary disease, so there is currently no method to prevent its appearance.

Hematuria (blood in the urine) is usually the most common form of presentation, so in the event of any bleeding with urine we must go to the doctor, since it always requires an exhaustive study to try to find the cause, which can be inconsequential as urine infection or renal colic, or more serious conditions, such as glomerulonephritis or this syndrome.

The presence of hearing deficits or vision alterations should also always be consulted with the doctor.

The descendants of those affected by Alport syndrome should see a doctor for a medical examination, in order to detect incipient alterations of this syndrome, such as: the presence of microhematuria or protein in the urine, undetectable without an analysis of urine.

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Hello Readers, I am Nikki Bella a Psychology student. I have always been concerned about human behavior and the mental processes that lead us to act and think the way we do. My collaboration as an editor in the psychology area of ​​Well Being Pole has allowed me to investigate further and expand my knowledge in the field of mental health; I have also acquired great knowledge about physical health and well-being, two fundamental bases that are directly related and are part of all mental health.

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