What Are Genetic Disorders?
Genetic disorders are inherited medical conditions caused by mutations in the DNA. These disorders present symptoms at birth, childhood, or adulthood. Genetic diseases are caused by a change in a part or whole DNA sequence. DNA is made of chromosomes, which carry genes. Each individual has 23 pairs of chromosomes in each cell. The first 22 pairs of chromosomes are similar in males and females, whereas the 23rd chromosome is a sex chromosome, different in males and females. The sex chromosome describes the sex of the individual. The genetic changes occurring in the DNA can be inherited from the parents to the children at birth or acquired by an individual during life.
The genetic disorders are classified as -
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Single Gene Disorders - The disorders caused by mutation of a single gene are called single-gene disorders.
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Chromosomal Disorders - The disorders caused by a transformation, missing, or changed part of a chromosome are called chromosomal disorders.
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Complex or Polygenic Disorders - The disorders caused due to the transformation of two or more genes are called polygenic disorders.
What Is a Genetic Kidney Disorder?
A genetic kidney disorder is caused by mutation or transformation in a gene, chromosome, or multiple genes. The mutations occurring in MYH9 and APOL1 genes are mainly responsible for genetic kidney disorders. Not all people with genetic transformation develop kidney disease. Certain factors such as smoking, drinking alcohol, being physically inactive, diabetes, hypertension, obesity, and other kidney diseases increase the risk of the development of end-stage renal disease.
The genetic disorders are inherited through their families as -
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Autosomal Dominant Inheritance - An individual affected by an autosomal dominant disorder has a 50 % chance of passing the transformed gene to each offspring. The chance that an offspring cannot pass the disease is also 50 %.
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Autosomal Recessive Inheritance - Autosomal recessive inheritance can be seen in an affected person with one copy of the transformed gene passed to the progeny. The chances of each individual having a disorder is 25 %, to be a carrier of the condition is 50 %, and the offspring will not be a carrier and will not have a disease is 25 %.
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X-Linked Dominant - A male can pass all the sex-linked diseases linked on the Y chromosome to all of his sons and X chromosome with 50 % to all of his daughters. A female can pass the disorder to 50 % of her daughters and all of her sons.
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X-Linked Recessive inheritance - The sons of a male with an X-linked recessive disorder will not get affected, and daughters can carry a copy of the transformed gene. However, the sons of a female with an X-linked recessive inherited disorder can have a 50 % chance of developing the disease. The daughters carry one copy of the transformed gene.
What Are the Types of Genetic Kidney Disorders?
The inherited kidney disorders present symptoms from common conditions to unique diseases. Some of the genetic kidney disorders include -
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Autosomal Dominant Polycystic Kidney Disease - Autosomal dominant polycystic kidney disease is the most common type of genetic kidney disorder. It is a progressive disease that finally ends in kidney failure. The condition is characterized by various cysts inside the kidney and pain in the back and head. Further signs are liver and pancreatic cysts, abnormal heart valves, kidney stones, brain aneurysms, and urinary tract infections. The treatment involves the correction of the symptoms and decreasing the severity.
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Congenital Abnormalities of the Kidney and Urinary Tract (CAKUT) - CAKUT is a single gene mutation kidney disorder. The disease can be characterized by renal agenesis, renal hypoplasia, and multicystic or dysplastic kidney.
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Alport Syndrome - An inherited kidney disease characterized by progressive kidney disease, hearing loss, and eye abnormalities. People affected with Alport syndrome present with hematuria (blood in urine), indicating kidney impairment. The syndrome is caused by genetic variation in collagen protein genes. Collagen is a protein that maintains normal function in the kidneys. The kidneys in Alport syndrome have tiny blood vessels in the glomeruli, which cannot filter the waste and extra fluid in the body.
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Nephronophthisis - Nephronophthisis is an autosomal recessive disorder characterized by scarring and inflammation of the kidney. In addition to it, the development of fluid-filled cysts can also be seen. The symptoms include increased urine production, excessive thirst, weakness, and exhaustion. Treatment depends upon the outcome and severity of the symptoms.
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Cystinosis - Cystinosis is an autosomal recessive genetic disorder that occurs when an individual gets a cystinosis gene from each parent. Such individuals are supposed to have a buildup of cystine that can lead to the formation of cystine crystals.
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Fabry Disease - An inherited disorder that is caused by an abnormality in the gene to form an enzyme, alpha GAL. As a result, the production of alpha GAL is little or absent. This disease affects the heart, nervous system, and kidneys.
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Gitelman Syndrome - An autosomal recessive inherited disease that is caused by abnormal SLC1283 or CLCNKB genes from each parent. The syndrome causes an imbalance of charged ions such as potassium, magnesium, and calcium. The symptoms include fatigue, salt craving, thirst, frequent urination, dizziness, low blood pressure, and heart palpitations.
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Nephrogenic Diabetes Insipidus - It is an X-linked recessive and autosomal recessive type of disease with the mutation of the gene ADHRV2. The clinical symptoms include insensitivity of the renal concentrating system to the effects of the antidiuretic hormone arginine vasopressin (ADH).
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Bartter's Syndrome - It is an autosomal recessive genetic disorder characterized by mutation of the gene coding for the furosemide-sensitive sodium-potassium transporter.
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Tuberous Sclerosis Complex (TSC) - An autosomal dominant inherited genetic kidney disorder occurring in individuals with a copy of the TSC gene from one parent. The disorder is characterized by seizures, intellectual disability, and developmental delay. Kidney symptoms are caused by tumors. Brain tumors generally grow in childhood.
How to Diagnose Genetic Kidney Disorders?
Genetic Testing:
It is a medical test that specifies modifications in genes, chromosomes, or proteins. Genetic testing can verify a suspected genetic condition and a person‘s opportunity to acquire or transmit a genetic kidney disorder.
Conclusion:
All people with genetic variations do not acquire kidney disease. There are other diseases and conditions that can run in the family but are not caused by genetic disorders. Instead, certain circumstances such as environmental facets, dietary habits, pollutants, or a mixture of genetic and environmental factors can be a reason for the outcome of the disease. An increase in the risk of the development of kidney disease can be linked to genetic variations. Genetic transformation leading to kidney diseases, diagnosis, classification, and development of new therapies can be made by molecular genetic techniques. Molecular genetic approaches are rapidly developing and can provide deep knowledge regarding genetic variations.
