- CONGENITAL HERITAGE (GENETIC) KIDNEY DISEASES
Many different diseases can lead to kidney failure. Chief among these diseases are diabetes, high blood pressure and nephritis. None of these are diseases that are definitely passed from mother or father to children. However, they may occur more frequently in some families. But some kidney diseases are hereditary, meaning they can be passed directly from mother or father to their child. There is a high probability that the same disease will be seen in the children of patients who have developed kidney failure due to such a hereditary kidney disease.
Which hereditary kidney diseases are seen in the children of sick people?
< The most common inherited kidney disease is adult polycystic kidney disease. Apart from this, medullary cystic disease/nephronophthisis, Alport syndrome and very rare familial gout can also occur in the children of patients and cause kidney failure. These diseases are not necessarily seen in all children of sick people. The risk of contracting the disease for each child is roughly 50 percent. In other words, one in two children whose mother or father is sick may have this disease. Diseases that are transmitted like this are called "autosomal dominantly transmitted diseases" in medical language.
How can it be understood that children are sick?
The first of the hereditary kidney diseases mentioned above are the first ones. Symptoms, examination and laboratory findings are different from each other. In adult-type polycystic kidney disease, many cysts form in the kidney and these cysts replace healthy kidney tissue, leading to kidney failure. The first sign of this disease is the appearance of kidney cysts on ultrasonography. In sick individuals, these cysts often appear in childhood, at the latest at the age of 20-25. If the child of a person with polycystic kidney disease is 25 years old and no kidney cysts are seen on ultrasonography, it is considered that he is not sick.
In medullary cystic disease/nephronophthisis, there are also small cysts in the kidney. The first symptoms of the disease may be drinking too much water and urinating a lot or anemia. ultrasonographer Some findings can also be detected. The first symptoms of Alport syndrome are similar to nephritis. Urinary bleeding, which is first seen under a microscope or noticed with the naked eye, occurs. In addition to bleeding, albumin may also be found in the urine analysis.
Can parents transmit kidney disease to their children even if they are not sick?
Yes. Sometimes, hereditary kidney diseases may occur in their children even though the parents are not sick themselves. This situation is frequently encountered in consanguineous marriages. Although both mother and father carry disease genes, they are healthy. However, when the disease genes inherited from the mother and father combine in the child, a serious disease that begins at an early age occurs. Diseases transmitted in this way are called "autosomal recessive diseases". These diseases are not necessarily seen in all children of carrier couples. For each child, the chance of contracting the disease is 25 percent; In other words, one in every four children has the disease. The most important examples of autosomal recessive kidney diseases that lead to kidney failure are congenital nephrotic syndrome (a disease characterized by loss of protein in the urine and swelling in the body in the first months of life), cystinosis (a disease that impairs kidney functions as a result of the precipitation of some substances in the kidneys), oxalosis (causing stone accumulation in the kidneys). a disease) and some types of childhood polycystic kidney disease and medullary cystic disease/nephronophthisia disease.
Can we protect our children from hereditary kidney diseases?
Autosomal The easiest and most effective way to prevent recessive diseases is to avoid consanguineous marriages. Some of these diseases can be diagnosed in the womb and termination of pregnancy may be considered with the doctor's decision. Autosomal recessive diseases should be investigated in children of people with known disease, starting from childhood. If the diagnosis is made before kidney failure develops, the emergence of kidney failure can be delayed with treatment.
It is possible to group congenital kidney diseases under the following headings:
1. Kidney dysgenesis
- Agenesis/Aplasia
- Dysplasia
- Hypoplasia
- Shape and position abnormalities
- Cystic kidney diseases
- Abnormalities associated with syndromes
- 1. Renal Dysgenesis
a. Renal Agenesis
Renal agenesis is incompatible with life if it is bilateral. Death occurs immediately after birth due to pulmonary hypoplasia. This entity is called Potter Syndrome. If there is oligohydramnios and absence of bladder and kidneys in prenatal ultrasonography (US), bilateral renal agenesis should be suspected. Other common causes of neonatal renal failure
Unilateral renal agenesis has been found to be more common in children of diabetic mothers and blacks.
To define hereditary renal adysplasia, renal agenesis, renal dysplasia, multicystic kidney or their combinations. It is a term used. Anorectal, cardiovascular and skeletal abnormalities may occur together.
Unilateral renal agenesis is usually detected during the investigation of other congenital abnormalities and different urinary system symptoms. There is compensatory hypertrophy in the contralateral kidney. There is VUR on the opposite side in 15%.
Some patients are born with a hypoplastic kidney or multicystic dysplastic kidney and may show complete cyst regression. If renal absence is determined by US, excretory urogram or renal scintigraphy is recommended. Because "ectopic kidney" may be present in some of such cases. If the opposite kidney is normal, renal functions remain normal for a long time.
b. Renal Dysplasia
The term diplasia histopathologically reflects primitive structures arranged focally, diffusely or segmentally, conditions resulting from abnormal metanephric differentiation. Non-renal elements, such as cartilage, may be present in them. If the entire kidney is dysplastic or full of cysts, it is called "multicystic dysplastic kidney". In multicystic kidney, non-functional cysts cover the kidney. Kidney size is highly variable. The incidence is 1/2000. Clinicians may incorrectly use multicystic kidney and polycystic kidney as synonyms. Polycystic kidney disease (PKD) is a genetic disorder and affects both kidneys. Multicystic kidney disease is usually unilateral and It is not hereditary. Multicystic dysplastic kidney is one of the most important causes of abdominal mass in newborns. Most cases are detected incidentally during prenatal US. VUR and hydronephrosis are detected in 15% and 5-10% in the opposite kidney.
Renin-mediated hypertension and Wilms tumor may develop in these cases. Because of these types of potential problems, annual monitoring is recommended. If there is an abdominal mass, cysts are growing, the size of the stromal core is increasing, and hypertension develops, nephrectomy is recommended.
c. Renal hypoplasia
It means a small kidney with fewer calyces and nephrons than normal. If it is unilateral, it occurs during the evaluation of another urinary system problem or during hypertension monitoring. Bilateral renal hypoplasia is the manifestation of chronic renal failure. Polyuria and polydipsia are common in the history. Urinalysis is usually normal. A rare form of bilateral hypoplasia is “oligomeganefronia”. The number of nephrons has decreased significantly, but there is marked hypertrophy.
Ask-Upmark kidney (segmental hypoplasia) also has kidneys that are smaller than normal. Generally. Severe hypertension occurs in most patients around the age of ten. Nephrectomy can control hypertension.
2. Shape and position abnormalities
During the development process, the kidneys normally move upward from the renal pelvis, reaching behind the ribs in their normal position. If normal ascending function and rotation are not completed, renal ectopia and nonrotation occur.
Ectopic kidney: can be located in the pelvic, iliac, thoracic or contralateral position. If it is contralateral, there is a fusion anomaly at a rate of90%.
Horseshoe kidney:It is a renal fusion abnormality. The lower poles of the kidneys may meet at the midline. It occurs in 1/500 births. However, it is seen in 7% of Turner syndrome cases. Other renal anomalies may also be seen in 30% of cases with horseshoe kidney. In these cases, Wilms tumor is four times more common. Stone disease and hydronephrosis are late complications. There is also an increase in the incidence of multicystic dysplastic kidney.
Crossed fused ectopia: One kidney crosses over the other and the 2 kidneys are united. Renal functions are generally normal. The most common finding in the left kidney is its fusion with the lower pole of the right kidney. The end of the ureter is unchanged. The clinical significance of such abnormalities becomes evident when renal surgery is required, blood flow may be variable and partial nephrectomy is more difficult to perform. Congenital heart diseases, single umbilical artery, and external ear abnormalities may occur together.
3. Cystic kidney diseases
Renal cysts can originate from any segment of the nephron or collecting ducts. They are epithelial-lined formations located in the cortex, medulla, or both.
Autosomal dominant polycystic kidney disease (ADPKD)
ADPKD Pathology ADPKD is characterized by cystic dilatation, any part of the nephron. It may be affected in part, and varies in size and distribution, but is always bilateral. Extrarenal cysts (liver, pancreas), cerebral aneurysms (Berry aneurysm), cardiovascular system abnormalities are less common in children. Genetics > Autosomal dominant inheritance is caused by at least three different genes. The most common of these, PKD1, affects approximately 85% of cases, is located on chromosome 16 (16p33.3). PKD2 is located on chromosome 4 (4p21-23)and is responsible for 15% of cases. Cyst formation begins with polystin-1 and polystin-2, which are the products of these genes. Diagnosis Molecular biology methods are not available for routine diagnosis, diagnosis is generally < It is placed with strong>US
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